Growing Yacon (Bolivian Sunroot)

In the United States, the crisp, sweet, crunch of yacon roots is a secret known mainly to gardeners. When I began to grow it, late in the last century, it was even less known, though it has been a popular food in its native South America for centuries.

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Yacon Leaves.             Credit: Pam Peirce

After I read about this plant in the book Lost Crops of the Incas, it took me three years to locate starts to grow. The low point was the first trip I took to a tropical plant nursery near my parents’ house in San Diego County. I had spoken to the proprietor on the phone. He assured me he had the plant for sale if I could pick it up, but when I got to the nursery, employees told me he was on a plant-hunting trip in South America. They were sure there was some yacon somewhere in the nursery, but they had no idea how to identify it, and I, having seen only a written description, didn’t either. So that was that.

 I tried again the following year. This time, a nursery worker told me the proprietor was somewhere in the nursery, but who knew where? I wandered amid the dense, tropical foliage lining the labyrinthine nursery paths, until I rounded a blind turn and practically walked into the man who could locate yacon for me!

Yacon is much easier to find now, so now many people enjoy its crisp, juicy roots. They are sort of like jicama, but more tender; sort of like watermelon, but a bit firmer. And their sweetness is from a sugar we don’t digest, so the roots are low in calories. Marketers are even touting yacon syrup as a healthful sweetener, though I’m sure the fresh, raw roots are even better for you, plus you get to enjoy their crunchy and juicy texture.

            This exuberantly large perennial plant, with its broad, furry, gray-green leaves, is, botanically, Smallanthus sonchifolius, a relative of sunchoke (Jerusalem artichoke) and sunflower. (In the fall, the small orange daisies that bloom atop the tall plants show the plant family relationship.) Besides yacon, it has been called Bolivian sunroot, Peruvian ground apple, strawberry jicama, and, by teenagers who so enjoyed my harvest, simply “the root.”

In mid- to late fall, when the leaves start to die, you can cut the stem back and dig up the harvest. When you do, the first structures you will see are the rhizomes, which look like Jerusalem artichokes. You will save these to replant for next year. What you eat are storage roots that dangle from the rhizomes. They range in shape, from spindle- to globe-shaped, and from a couple of inches in diameter to 6 or 7 inches across. Under a thin brown skin, they are white inside. (The storage roots are delicate, so dig carefully.) They are said to be sweeter after a frost, or after storage in a refrigerator for a couple of weeks. I often eat roots as soon as I dig, and have found them variable in sweetness, but always worth eating.

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Yacon rhizome and storage roots. Pam Peirce

            Break or cut the roots from the rhizomes, wash them, peel them with a vegetable peeling tool, wash again, and slice them into pieces. I have found them welcome in lunch boxes and useful in salads. (For example, I have used slices of yacon in place of jicama in a salad that includes blood orange and avocado. The recipe is in Golden Gate Gardening.) They could, I suppose, be cooked, but I have never been inspired to do that.

            If you are cutting back several plants, leave a foot or so of the stems, so you will know where to dig later. Divide and replant the rhizomes by late winter, before they start to grow again. A full plant will grow from a small rhizome, so you may have extra to share with friends.

            This is an easy plant to grow. Other than an occasional nibbled leaf, mine have not seen pest damage. The plant is so big I thought it wouldn’t do well in a container, but it is so tough and productive that it has even produced a small crop of roots in a big pot. The fact it was in a pot made the roots easier to dig.

            Look for yacon propagation rhizomes in winter, when the plants are dormant, or in early spring. Annie’s Annuals (anniesannuals.com, 888.266.4370) carries them. You can also purchase yacon from the fruit nurseries Raintree Nursery (raintreenursery.com, 1-800-391-8892) and One Green World (onegreenworld.com, 1-877-353-4028).


Saving Miner's Lettuce Seed

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If you live in California, and want to grow this wonderful edible native plant, miner's lettuce (Claytonia perfoliata), now is the time to save some seed. I wrote about it in Golden Gate Gardening, as an edible weed, but it's so good it is worth growing on purpose.

If miner's lettuce grows somewhere nearby, you can collect it now, save the seed. Then, in Fall, you can scatter it. It should be well up in December, and then will make its lovely, succulent leaves, so delicious in a salad, until the following April.

To find seed for next year, look now, in late April or in May, for plants with circular leaves that are still green and have long flowering stems. Thse will have a number of seedpods forming on the stems, with maybe a flower at the top. Gather some of these leaves, or, if you like, a whole plant bearing a few of them. 

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Spread what you have collected on newspaper indoors. Use a fully opened piece of newsprint, or maybe two or three together. As the pods dry, the seeds will pop out, and will actually jump up to a couple of feet from the pod. Thus you will find them all around the paper, or, if it is too small, on the floor nearby. The seeds are small, rounded, and shiny black. They have a white tip on one side where they were attached to the pods.

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The process will take a week or two. Here you can see the seeds and bits of pods around a plant that is drying. After the seeds pop out, you will have to separate them from the chaff. You can do this with various kitchen items, such as collanders or sieves. I used a sieve, which left me with some tiny fine chaff mixed with seeds, then blew lightly to get the chaff to fly away. It doesn't have to be perfect, of course, but seeds are easier to sow if they are free of debris, and also any bits of plant mixed with them can bring moisture that can lead to decay.

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Here's a closer view of some of the seeds before I cleaned out the chaff. After you've removed most of the chaff, keep the seeds in an open dish or jar for a couple more weeks, to make absolutely sure they are dry. Then you can store them in a paper packet or you can close the jar. Be sure to label your seeds as Miner's Lettuce and write the date of the year you saved the seed.

Make a note in your calendar so you'll remember plant the seed in October. Scatter it in an out-of-the way corner of your garden, in moist soil you have amended and dug. Scratch the soil surface a bit after you sow, pat the surface lightly, and then water. Water to keep the surface moist if rains don't do it for you. The seed leaves are long and narrow. The first few leaves will be triangular. Then the mature leaves form, the round ones. You can eat them, flowers and all, after the flowers start to form in their centers, but when the flower stems elongate they are ready for another year of seed saving. Or just let some fall in place, in hopes the plants will self-sow!

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Here's a salad containing miner's lettuce, corn salad, edible flowers, and some cut up chard stems.


Watsonias--Wildly Successful Plant of Late Spring

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In April and May I look for Watsonias. I love these big, graceful plants, with tall stems of trumpet-shaped flowers. These easy-to-grow bulb plants are one of South Africa's best gifts to Bay Area gardeners. They are among the 50 plants I featured in my book Wildly Successful Plants: Northern California, as very well suited to our gardens and easy to grow. (See cover, at right) They thrive in cool or hot summer areas. I don't know of an insect pest or a disease that troubles them, and snails don't seem interested either. 

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The red one in the two photos above is a hybrid, one of several usually available in nurseries for fall planting.  

After you plant the bulbs (correctly, they are corms), the leaves begin to grow with the first rains. They usually don't need any irrigation beyond rainfall to mature and bloom. Even last winter, which was rather dry, I didn't water mine, though I might do so in a really, really dry winter. After weeks of glorious mid- to late spring bloom, they die back in early summer. You don't have to water them in summer either. These are truly drought-tolerant plants! If the soil is well-drained, they won't mind a little summer water, but if kept too moist, they won't bloom as well the following year.

            The reason Watsonias do so well here is that they are from the Cape Region of South Africa, which has a similar rainfall pattern to ours. The regions where they grow have poor, sandy soil, so our rather poor soils are not a problem, though they can take moderate fertility, if you want to dig in a little compost. They stand up to wind and cool temperatures. They thrive in foggy microclimates. Full sun is best near the coast, but half-day will do. If you garden in a hotter inland microclimate, they will appreciate the hot soil while they are dormant. The spring-blooming Watsonias described here are hardy to 10° F.

            It's best to cut the flower stalks after they bloom and, in mid to late summer, cut brown leaves to the ground, before new green ones start to grow, so that they won't distract from next year's show. The deadheading and cutting back is really the only annual care they need.

            Watsonias are grand at the back of a border, where their 5- 6 foot tall flower stalks will be seen over other plants. Another way to grow them is behind a hedge, so they stand above it when in bloom, disappear when they die back. Or mix them into a narrow border with other plants of similar height--shrubs or other tall perennials. In addition to ornamenting the garden, Watsonias make good cut flowers.

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            Most of the Watsonia plants I see growing are hybrids, with peach, pink, or red flowers, which are readily available at nurseries for fall planting. I also see the pink or white-blooming ones that represent the species, Watsonia borbonica, especially in older gardens.

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I think the pink one in the three previous photos is the species, Watsonia borbonica. It is described as having "violet" stamens, and these look violet to me.

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This white one may be Watsonia borbonica ardernii, a subspecies that was discovered in the wild.

            Plant the corms about 4 inches deep and 6 inches apart. You can plant in a circular area to get a nice clump, or could plant in a row.

            While the plants will thrive with little care, if you have time, and want to groom your plants to keep your garden looking at its best, here is what to do:

            While the plants are blooming, remove spent flowers every few days. They will fall off in your hand at a slight pull. When the top flower of the central stalk of flowers has bloomed and faded, cut that stalk off where it joins a lower flower branch that still has buds or open flowers. (You will need hand pruners for this, as the stalks are tough). When all of the side stalks have finished blooming, cut the entire flower stalk short enough that the cut end won't be visible above the leaves.

            When all of the flower stalks have been cut, you can ignore the plant until all the leaves turn brown, or you can go out every couple of weeks and remove brown leaves. It is up to you. But when all the leaves are brown, cut them as short as you can. You will need sharp pruners to do it. Don't wait until the green "swords" of the new leaves push through in fall, or you will have a devil of a time avoiding injury to the new leaves!

            That's about it, until, a number of years later, you might see that the clump is blooming less, or only near the edge, or that it is a bit too wide for its location. Then you might want to go out when the plants are dormant, in summer, and either remove some corms near the edges to reduce the clump size, or actually dig the whole thing up and replant corms.

            Either way, you will have some corms to plant elsewhere or to share. Full sized corms are 2-3 inches across and will probably bloom the following spring. Smaller ones (cormlets) will take 2 or more years to bloom. If you dig the whole clump, you will probably have more corms than you know what to do with, and may want to discard the smaller ones. (Or maybe go into the Watsonia corm business.)

            One more tip. You can grow Watsonias in a big pot, say 15 inches across for a group of corms, but in a pot you will need to give them a bit more care. From the time the plants start to grow to when blooms are starting to fade, fertilize lightly from time to time, and water regularly. You don't want the mix to be soggy, but unless rain is keeping it wet, water when the top inch is dry.

Learn about 49 more easy, beautiful garden flowers in Wildly Successful Plants: Northern California.

 


Late Blight Sample Sent for Analysis

I sent my first specimen of tomato/potato late blight off for analysis this week. I found symptoms on a purple potato that grows in the City College of SF garden. I sent it to a lab in Oregon, as I described in my March 2nd post, to become a part of the usablight.org project. They want to know which "clonal lines" of this disease organism are causing the disease in various parts of the country. For my part, I want to know which ones we have here in the Bay Area. Once we find that out, we will be better able to predict which tomato or potato varieties might resist the disease in our region.

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This is the photo of the specimen I sent to the usablight.org lab. They want us to send leaves that are still partly green, like these, but clearly infected. The whitish stuff on the surfaces is, I hope, spores of late blght.

If you want to take part in this survey and find out more about your particular strain, or, more correctly, clonal line, of late blight, go to usablight.org and learn how to submit samples. The first step is to have them send you a copy of the permit that will let you ship your disease samples across state lines to be tested in a lab in Oregon. Do this soon, so you will have the permit in hand when late blight rears its ugly head in your garden.

If you have overwintering potatoes, you might see late blight soon. In last year's tomato trial, the disease showed up at the end of July. Gardens with cool, damp, foggy weather are more likely to be affected by this disease. Spores fly through the air from other infected plants, land on your plants, and begin to grow. Please see the March 11, 2012 post for more details.


April 14th Plant Sale will Have Late Blight Resistant Tomatoes

I just learned that the San Mateo/San Francisco Master Gardeners will offer three late blight resistant tomato varieties at their spring tomato and pepper plant sale on Saturday April 14th, 9:00am-1:00pm, rain or shine.

The sale will be held at the Elks Lodge, 229 West 20th Avenue, San Mateo. They will have 'Defiant PhR', 'Mountain Magic', and 'Golden Sweet' and will also have lots of other tomato and pepper varieties, starts of popular herbs, and gently used gardening books.Go early for the best selection of blight resistant tomatoes.

I know if you live in SF, it's a slog. If you don't ordinarily drive, it may be worth carpooling down or renting a carshare for a chance at some tomatoes that stand a chance against late blight.Parking for the sale is free.

For more information about the sale, call 650-726-9059 Ext. 107, Mon & Thurs, 9:30am-4:30pm or go towww.ucanr.org/sites/MGsSMSF/Special_events/Tomato_Sale.


Battling Tomato Late Blight

 Note to readers: I wrote this to add to information in the SF Chronicle Article that will appear in the print version of the paper on March 4, 2012. The article will not be availabe on sfgate.com until Monday, March 5th, so if you are here on Saturday or Sunday, and want to find out what is in the original Chronicle article, check back on sfgate.com on or after Monday.

Are you losing tomato plants to tomato late blight? This disease has been killing tomato and potato plants in the Bay Area for several years, and I have been trying to find tomato varieties that will resist it. I reported last year’s trial in the SF Chronicle and on sfgate.com. (If you haven't seen that articlet yet, you can find it at http://www.sfgate.com/columns/goldengategardener/archive/ .) In that article, I promised more details here, in my blog, so here they are. (Note: If you are an expert reading this post, and have corrections or more information to offer, please comment or send me an email through my website at pampeirce.com.)

            This is a long post, so I will tell you what is in it here at the beginning. The first section explains what late blight is, with photos of symptoms. The second section is a brief explanation of ways to try to reduce late blight damage in your garden. Section 3 tells you how to set up a tomato variety trial yourself, with photos to show you how we did it. The fourth section includes some details about genetic resistance to late blight among available tomato varieties, with photos of the fruits of the ones that succeeded in the 2011 trial. The fifth section tells you how to send samples of your blight to the website www.usablight.org in order to identify the clonal line(s) of the blight present in your garden. Then, finally, at the end of this post, is the list of varieties that also appears in the sfgate.com column, showing you which I trialed in 2009 and 2011, plus a few new varieties that I haven't yet trialed.

What is tomato late blight?

            Tomato late blight is caused by the oomycete Phytophthora infestans. (Oomycetes are organisms that used to be called “water molds.”) The disease-causing organism is in the same genus as the one that causes sudden oak death, Phytophthora ramorum, though the two diseases infect different groups of plants.

            “Tomato late blight” is a common name. Because the same organism also infects potato plants, it is sometimes called “potato late blight” or even “tomato and potato late blight.” It can also infect petunias, which are in the same plant family; though I have never heard it called “petunia late blight.”

            The words “late blight” are found in the common names of other plant diseases that are caused by different disease organisms. For example there is “celery late blight,” which is caused by the fungus Septoria apii. (Just one more example of why it is important to know the scientific name of a living creature, even if you commonly use the common name.)

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The first symptoms are darkened areas, briefly topped with white fuzz. This lesion is on a potato leaf.

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If a plant is sucseptible, lesions start to appear all over and spread, killing leaflets, whole leaves, and stems. If fruit has formed, it soon has greasy, brown "shoulders." If it ripens at all it wil have poor flavor.

            The tomato disease that causes our grief is known as a “late” blight because the symptoms typically show up only when the plant is mature, the fruit has set, maybe even some has begun to ripen. (By the time it shows up, we have usually had a couple of months to tend the plants and eagerly monitor the progress of setting fruit, so our disappointment is even deeper than had the disease struck early, before we had developing fruits to mourn.) The late onset happens because the mild temperature and moist air that encourages the spores to grow is likely to occur later in the summer, and also because as infections start to occur, there are more spores to blow about in the air and spread the disease.

            It’s important to know that the spores are not in the soil, but are blown in the wind from plant to plant, from as far as several miles away. They also are not carried in seed.

            It seems that we are fortunate, if that is possible, considering the damage this disease causes if it strikes, because so far, we have only asexual zoospores in our part of the world. These zoospores do not survive in soil, only in living or recently living susceptible plants. Because of this, we can get most of the spores out of our gardens by making sure we have no living plants that can get the blight in our gardens for four months in the winter. In our community garden, we remove all living and dead material from tomato, potato, petunia, and wild solanums (nightshades) from the garden in November through March. (If you do this, you also have to watch for and remove volunteer potatoes that can come up in winter and sometimes get late blight during a warm spell in winter and early spring.) While removing susceptible plants in winter can reduce the number of spores around in summer, it can’t, of course prevent new spores from blowing in, so you still may find the disease in your garden, but at least it isn’t a certainty.

            (If the form of the organism necessary for sexual reproduction were to find its way here, we could have sexually produced oospores here that would survive in soil and live longer than the asexual zoospores. Fortunately, there is no sign of this having happened or immediate expectation that it will.)

 Protecting Tomato Plants from Late Blight

            To protect plants from this disease, gardeners try to keep leaves dry, shelter plants from spore-bearing breezes, or spray them with a protective substance. In the Northwest, tomatoes are often grown under row cover (polyester fabric that lets most light through) or plastic hoop houses to keep rain off. In the Bay Area, we aren’t likely to have rain in summer. Our high humidity can provide enough moisture for the spores to germinate, but you may as well avoid wetting the leaves when you water, and you can try putting plants under cover if you like.

            Fungicides based on copper compounds and the fungicide Serenade are both registered to prevent tomato late blight and are permitted to organic farmers. Either kind of fungicide needs to be sprayed starting from the time you set out your transplants, and continued all season following label instructions, which are to spray more or less weekly. If they are used heavily, copper compounds can increase the copper content of soil so much that plants grow less well, so perhaps they aren’t the best idea. I did try spraying a copper fungicide one year. I found it a lot of work to spray my small planting so many times—and the plants still got late blight.

            I haven’t tried Serenade for late blight yet. It is based on the harmless soil bacterium Bacillus subtilis, and it is worth a try if you don’t mind the spraying. (I was able to prevent onion downy mildew from overtaking my perennial “walking onions” by spraying them with Serenade, so I do know that it works against that disease--another one listed on its label.)

 Looking for Resistance to Tomato Late Blight

            In addition to the winter clean up, which is basic to prevention, I have been trialing varieties that might stand up to this disease. I would very much like to grow my favorites, such as ‘Cherokee Purple’ or ‘Old German’ heirloom varieties, but they get late blight. I am looking for varieties that are resistant to late blight because I’d rather have some tomatoes for sure than spend all my time spraying or covering my plants and likely still losing them to the disease.

            The history of my tomato variety trials is in my sfgate article, (http://www.sfgate.com/columns/goldengategardener/archive/ ) along with a summary of how to do such a trial. Here are more detailed instructions for those who might want to carry out a trial.

            To do a trial, you need one or more experimental varieties (ones you have some reason to believe will resist the blight) and one control variety (one you know will get the blight). The control variety is there to prove that the disease was present in your garden, because if it wasn’t, you didn’t prove the experimental ones would resist it. I have been using ‘Celebrity’ as a control plant. It is an early hybrid that has short plants and resistance to quite a few diseases, though not to tomato late blight. You could choose another control, or could duplicate my choice to stay as close as possible to experiments that have been done already.

            The more plants of each variety you can use, the better, since you don’t want an accident, such as a broken stem or a virus attack to wipe out your one plant of a particular variety, and you want to know that your result is true in more than one plant (though because hybrids are more or less identical, what is true of one plant is more likely to be true of another than if you are groiwn heirlooms). I try to have at least 2 plants of each variety; use more if you have lots of space.

            Now you will have two goals. The first is to give all of the varieties in your trial as close as possible to the same conditions, so that resistance or susceptibility to late blight is the only difference. If you can’t treat them exactly the same (for example, you can’t grow them in exactly the same spot in the same year) you will randomize that aspect of their conditions. Your second goal is to keep track of what happened and record it. This you will do by making sure you know which plant is which and by recording whether the blight struck each plant over the course of the growing season.

            Start seeds for all of the varieties in your experiment on the same day, to ensure that they will be at the same age. Label each kind with a tag that gives the date you planted the seed and the name of the variety. When they have a couple of true leaves, pot them all into individual 4” pots on the same day. Make sure each 4” pot has a label with the date of planting, (date of potting up is optional) and the name of the variety. Don’t lose track of your varieties!

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On planting day, all of the plants are the same age and have been treated the same as they grew. Each pot includes a label.

            Choose a place to plant your experiment. Give the plants adequate space. We had 3 rows of 4 plants each in 2012. The plants were about 18” apart, the rows 3’ apart. Prepare the soil of the entire area in the same way. That is, spread any organic amendment or fertilizer evenly and then dig it in. If you plan to set up a drip system, set it up over the entire bed so that all the plants will be evenly watered by it. We used a half-inch tubing down the long side of the bed and quarter inch drip line with emitters every 6 inches. We ran two of the emitter lines along each planted row, one on each side of the plants.

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Spread organic soil amendment and any fertilizers you plan to use evenly on the bed and turn soil once to dig them in. Shown digging is David Elhami.

            Wait until mid-April or early May to plant out your seedlings, so the air and soil have warmed nicely. On the day you plant, have handy a hole-punch, twist-tie, paper and pencil. Before you plant, randomize your planting, as follows:

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Essential for setting up a tomato variety trial are hand-operated single-hole punches and twist-tie, for attaching labels to individual plants.

            Choose the seedlings you are going to plant and write the name of each on a small piece of paper. If you have two of each variety, make two paper names for that variety. Fold all of the papers up to conceal the names and draw names at random. (I like to draw them from a garden hat as a sort of joke, but you can draw them from whatever container strikes your fancy.)

            Make a map on a note pad. Start at one corner and make x’s to mark where the plants will be. Start in one corner, and as you draw names, write them on the map—progressing across the row and starting on the next row until you reach the end. With your randomized planting, you will reduce the chance that differences from one side of a bed to another, such as shade or wind patterns will throw off your results.

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This photo shows the making of the randomly arranged map. I draw variety names from an actual hat, just for fun, but you could use any container. Shown, left to right, are Donna Mandel, Pam Peirce, and Ken Jacobs.

            Now plant the tomatoes in the arrangement described on your map. As you plant each one, use the hole-punch to punch a hole in the label and use a piece of twist-tie to fasten the label to the main stem of the plant. be careful not to make it too tight. You want room for the stem to get a little thicker without being strangled.

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A labeled plant, with the label attached to the main stem. Make sure the twist tie is loose, so the stem can thicken a bit before you move the label higher on the growing plant. Note driplines on either side of the row.

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Here is the entire planting on the first day, April 16, 2011.

            Water well when all of the plants are in the ground, and water as you would tomatoes normally from then on. Probably best not to sprinkle water on the plants after the first day, but on that day it can reduce the chance of wilting.

            As the summer progresses, you will have three goals: 1. Keeping track of which variety is which, 2. Supporting your plants, and 3. Recording what happens vis a vis late blight.

            In order to keep track of the varieties, every 2 or 3 weeks we removed the hole-punched labels and moved them higher on the plant. We were careful that they were on a main branch, so it would remain clear which plant each was on, and so that we didn’t lose track of them when a small branch or leaf died. Of course we did have the map we made as a backup, but is nice to be able to see which plant is which at a glance.

            In last year’s trial, we supported the plants using the chainlink fence that was at one side of the bed, tall bamboo stakes and jute twine. We tied the twine to the fence, then wrapped it around stakes along each tomato row, then tied it to a stake at the end away from the fence. We used two pieces of twine per row, one on each side of the plants. As the plants grew, we used more twine at higher levels.

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A section of a row showing how two lengths of twine are used, one on each side, and how it is wrapped aroung stakes at intervals along the row to support the plants. This was shot on May 18th, 2011.

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Here is the planting on July 13, 2011. Nice tall green plants, but two weeks later, the damage had begun.

            Periodically, we observed to see whether late blight had appeared. We didn’t stick to a strictly regular schedule, since we weren’t interested in the exact progression of the disease, but did check every 3-4 weeks, and were able to tell which plants died first and which had fruit set, etc.

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Here I am, on August 11, 2011, recording relative damage to the plants. Note the plant label, which has been moved higher on the plant twice to make identification fast. The plant with the label is 'Golden Sweet'. The still-green plant behind me is 'Defiant PhR'.

            Need I say that, other than watering at ground level to keep leaves dry, an ordinary precaution I would always take when growing tomatoes, I didn’t take any measures to prevent or avoid late blight? I didn’t put them under cover or spray them with anything. In fact, I grew the trials in locations where late blight was definitely a problem in the previous year, just to be sure my experimental varieties had something to resist.

The Genetics of Tomato Late Blight Resistance

            There are two aspects of genetics that affect resistance. I am not going to be able to explain them in great detail here, but here are a few facts. The first aspect is the genes that provide the tomato variety with resistance.

            In last year’s trial, I grew 4 varieties I obtained from Johnny’s Selected Seeds. Rob Johnston, the founder of that seed company, told me that two, ‘Golden Sweet’ and ‘Plum Regal’ had one gene that provided resistance to late blight, and they were heterozygous for that gene. That is, it was on only one chromosome of a pair. The other two varieties, ‘Mountain Magic’ and ‘Defiant PhR’ had two genes that provide resistance. They are heterozygous for these genes, meaning that each of them appears on only one chromosome of a pair.

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'Golden Sweet' died in my USF planting, but I did get fruit in my community garden, in a warmer microclimate, and where we have been taking out susceptible plants in winter to reduce the number of spores in the garden. The fruits are small, but were indeed sweet.

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'Mountain Magic' was alive, with some damage, at the end of my USF planting. It set some fruit there, but only ripened a few of the fruits it set. In my community garden, it ripened plentiful fruit. The fruit is about 1 1/2 inches in diameter and has an average flavor.If you look carefully, you will see a couple of brown stems, lost to late blight damage.

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'Defiant PhR' had only minor damage at the USF plantng, but didn't set fruit. However, in my community garden, the one plant had 9 pounds of fruit. Size varied, but the biggest was over 3 inches across. This is a beefsteak-type, meaty fruit, with good, though not excellent flavor.

            In my trial, the ones that were heterozygous for two resistance-endowing genes fared better than the ones that had only one of them. Johnston says when varieties have been bred that are homozygous for these genes, that is, have them on both copies of a chromosome pair, resistance should be even better.

            I don’t have details about the genetic reasons for resistance of other varieties, such as ‘Juliet’ or ‘Legend’. The only other fact I can relay is that some wild tomato types have resistance through different mechanisms than the above. Examples are some cherry tomatoes and currant tomato, which is a different species than most tomatoes.

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In 2011, 'Juliet' died at USF, but in 2009 and 2010, it produced fruit in trials in my community garden. This fruit is smaller than an average past tomato, but larger than a plum tomato. Flavor is good, not great, but production is very good.

            The second genetic aspect, the other end of the resistance equation, is that the late blight organism is not genetically uniform. The correct term for the variations are “clonal lines.” They are clonal because they reproduce asexually, thus they are identical to their parent organisms. Why are there different ones? Presumably due to mutations that appear from time to time. There have been 24 clonal lineages in the US, but some may have died out. In any given year, there may be 4 or 5 active ones.

            I have made slow progress on tying tomato variety resistance to clonal lines of the late blight organism. I do know that ‘Legend’ resists US3 and US11. And I know these aren’t the clonal lines we have, because ‘Legend’, touted as a breakthrough in late blight resistance, dies first in my trials.

 What Clonal Lines do We Have?

            When I realized that resistant varieties may have resistance to specific clonal lines of late blight, I saw the importance of finding out which clonal lines we have in the Bay Area. Until recently, I was having difficulty finding this out. The breakthrough this year is locating the website www.usablight.org . This USDA-funded project is a national consortium of late blight researchers. They don’t know what clonal lines we have, but they want to know!

            You can help find out by submitting samples of your infected plants. Do this by going to the website and clicking on “reporting outbreaks,” then on “first time registration.” Register now so you will be sent a copy of the APHIS permit you will need in order to submit samples, since they will be shipped across state lines, to a lab in Oregon. Once you have the permit, you will be able to print copies of it to include with your samples. They prefer leaflets that have blackened lesions, but which have not yet wilted, and would like at least five examples in a sample. You register your sample online, so you will get a sample number to write on the sample bag before you send it, and can then use that number to track your results. You also print out a sample submission form to include with your sample, and write the sample number on that too.

            Full directions are on the website. I encourage you to look and register now, so you will be ready when the disease shows up.

A List of Tomato Varieties You Might Like to Try

            Here is a list of varieties I have trialed, plus a few I haven’t yet, as reported in my Chronicle/SFGate column, follows. (See that article at http://www.sfgate.com/columns/goldengategardener/archive/ for full trial results.) My best results so far have been with ‘Juliet’, ‘Defiant PhR’, ‘Mountain Magic’ and, in a warmer SF microclimate, with ‘Golden Sweet’. As seed sources for varieties listed below, start with Johnny’s Selected Seeds and Totally Tomatoes.

Note: Numbers (i.e. “70-75) indicate days from transplanting to first ripe fruit under normal conditions, though San Francisco plants may be slower. Det=Determinate or short plant. Ind=Indeterminate, or tall plant. These varieties are listed in order of fruit size—smaller to larger. For more information, such as flavor and other disease resistance, see seed catalogs.

*in my 2009 trial, **in my 2011 trial, ***in both trials

*Currant tomato—70-75, Ind, fruits under ½”, avail in red, yellow, and white. This is Solanum pimpinellifolium, a different tomato species that has some resistance.

*Matt’s Wild Cherry—60, Det, fruits marble-sized, red, some resistance.

*Tommy Toe—70, Ind, ½ -1” round red, fruit, some resistance

*Koralik—61, Det, 1” fruit, round red, some resistance

Red Pearl—58, Ind, 1 oz. oval fruit, said to have intermediate resistance

**Golden Sweet F1—60, Ind, oval, grape-sized yellow fruit, moderate resistance

**Plum Regal F1—68, Det, 4 oz., oval, red fruit, moderate resistance

***Juliet F1—60, Ind, 1½-2 oz. oval, red fruit, in clusters, moderate to good resistance

**Mountain Magic F1—66, Ind, 2 oz., red fruit in large trusses, good resistance

**Defiant PhR F1—70, Det, 5-7 oz. round, red fruit, good resistance

***Legend—70, Det, 4-5 inch, round, red fruit, poor resistance in my trials.

Ferline F1— Ind, 5 oz., round, red fruit, listed as “tolerant” of late blight.

Old Brooks--70, Ind, large fruited, said to have “superior” resistance

Please do write me if you have questions or any results to report. You can send me email at home@sfchronicle.com or write a comment into this blog.


Who knows what this is?

In mid-November we wee walking on San Bruno Mountain, at the south end of San Francisco when we came upon this plant with white berries. I think it's a California native shrub, but I don't know its name. My best guess is a viburnum, but I am only about 20% confident of that guess. So this time, I put the question to you who are reading this blog. Do you know what species this is?

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In the spring, this plant had flat clusters of white flowers. I shot those too, but don't remember the exact date, and don't know if I can find the images.So, any guesses from just this photo?

 

 


Dramatic Tree Dahlia Success

In November, the big news in our home garden was the success of our tree dahlia. It began to bloom at the end of October and still had a few blossoms the weekend after Thanksgiving. It was so tall the flowers were at the level of our second story window. This is such big news because the tree dahlia we had previously, a single-flowered white one, was such a failure.

The white one grew tall all right, and it bloomed too. It's first buds opened just at Thanksgiving and there were plenty of buds. However, at the end of November or the first week of December, there was usually, seems like always, a big wind that lasted 1-3 nights. At the end of it, the flowers and buds were mostly gone and most of the leaves had also broken off. Then all we had was a blackened skeleton until we got tired of looking at it and cut it down. Such a disappointment.

But this one not only begins to bloom a month earlier, but also, when the wind howled three nights in a row last week, the leaves survived! So we had a glorious month of lavender flowers and now the plant is still rather attractive as it soaks up the last bit of sunlight before its annual cutting back. March is the suggested month for cutting back, and we are grateful to have an attractive plant to look at until then.

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So the moral is that all tree dahlias are not the same. This plant, native to South Mexico and Guatemala to Colombia, is Dahlia imperialis. The species has white, pink, or lavender flowers; single or double. (Because it is a composite flowerhead, "double" means that it has more than one ring of showy ray flowers around the small yellow disk flowers.) Are all white-flowered ones earlier and more delicate in wind? What about double ones? I have no idea. But I'm glad we found a way to enjoy it in our windy garden.

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Naked Ladies--Wildly Successful Plant of the Month

In California, August is the month of the naked ladies. They are to be found dancing in gardens and along roads up and down the state. They dance, however, only in the wind, being rooted firmly in the ground--not wild California women, but pink lily-like blossoms of the plant Amaryllis belladonna. The fanciful name was inspired by the fact the plans have no trace of leaf when they are blooming.

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These, in our neighborhood, were planted behind a low privet hedge, so they peek modestly over the top when viewed from the street. (Not everyone finds them shocking, though, in Italy, they have the much more modest common name of Madonna lily, and in Spain, a name that translates to "Girls going to School.")

Below, I shot a cluster of them close up, so you can see the big bulbs at the top of the soil.

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This is a plant of mysteries. The first is the absence of leaves when it blooms. The explanation for their lack is that they have strap-like leaves in winter that you could easily mistake for Agapanthus leaves. They dry up completely well before the flower stem emerges.

The second mystery is why they sometimes refuse to bloom. In the wild, in the chaparrel-like fynbos of the Cape Province, they bloom only after a wildfire strikes--which happens every 5 to 40 years. In gardens, they tend to bloom every year, but if they are in shade in winter and spring, they may not bloom at all. One guess is that the wildfires remove other plants that shade the leaves in winter.

In South Africa, botanists puzzled for a long time about how the flowers were pollinated, considering a hawk moth, carpenter bees, and other bees. Whatever does it there, something also does it here, because seeds do form. They are soft pearly pink or white balls the size of BBs. I germinated them in pots, just to see, but they don't usually germinate in the garden. This is probably because fall rains are later here than in South Africa, so the delicate, fleshy seeds dry out before they can grow.

These plants grow nicely in unwatered parts of the garden. They rarely need any irrigation at all, being from the western, Cape region of South Africa that has a climate very similar to ours--wet in winter, dry in summer.You'd only need to water a bit in an unusually dry winter. And, while the plant has no need for summer water, it can tolerate a moderate amount of it in spring and summer in soil with good drainage, meaning you can grow it in the same bed as other plants that are moderately drought-tolerant. The bulbs are best left alone for a number of years to produce large clumps.

A good time to plant naked lady bulbs is late summer, when they are most dormant. If you are dividing an existing stand, dig them as soon as the blooms fade.

In South Africa, naked ladies are often interplanted with native bulbs that bloom at other times, such as spring blooming Agapanthus or winter blooming Chasmanthe. (Chasmanthe is a tall, orange or yellow-flowered plant often mistaken for crocosmia here.)

These were among the South African bulbs Thomas Jefferson obtained and tried to grow in his greenhouse, though in general, he wasn't a very successful greenhouse operator and soon gave up, deciding to use the greenhouse as a sun room instead. By 1850, the bulbs were introduced to California, which accounts for the fact they are sometimes seen blooming in places where no one lives now. They have survived in abandoned farm sites and on Alcatraz Island, where they were part of the prisoner or employee gardens recently rennovated. (While they persist, and multiply, they don't generally spread far from the original planting, so if they were planted in a row, the row remains, just blooming more profusely after many years.)

Gus Broucaret, instructor of Horticulture at City College of San Francisco tells me that as a boy in San Francisco in the 1930s or 40s, he would have dirt fights with his friends on undeveloped hillsides, and then dig up a naked lady bulb, slice it open and use the sudsy sap inside to clean their hands before going home to face mothers who didn't much approve of their dirtying play.

Naked ladies are deer and gopher resistant and are fragrant. If you have enough to cut as well as ornament the garden, you will find they are excellent cut flowers.

A similar plant, of interest to those with smaller gardens is Nerine bowdenii, which has pink flowers on bare stems to 2 feet tall in late summer. 

There is much more on Amaryllis belladonna and other easy heirloom California garden plants in my book Wildly Successful Plants: Northern California, available in many local bookstores and nurseries. (See cover at right.)

 


Disease of Fava Beans--Be Very Afraid

Recently I saw a disease on fava beans that was unfamiliar to me. It wasn't rust, which makes rusty brownish pustules on leaf undersides. No, these were nasty brown spots on the leaves that merged, became almost black, and destroyed the leaves. My diagnosis is chocolate spot disease, which is caused by the fungus Botrytis fabae.

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Here is an early stage. Then the spots merge and darken. The leaf below is on its way out.

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Notice the tear in the middle of the leaf, caused by dead tissue.

I don't have a description of this disease in any book, though one, The Self-Sufficient Gardener, by John Seymour, mentions that "horse beans", the smaller favas farmers feed to livestock, are more susceptible to it than the larger ones humans usually eat. This book is an English publication, and favas are an Old World native bean, so it is probable that they have had some fava diseases longer than we have.

Be that as it may, when I read the Wikipedia article here, I realized this disease could spread fast once it appears. The spores can be carried on or in the seed and can also form resting bodies that lay in wait in the soil until you plant the next fava bean crop. It can also survive "in crop stubble and residue." (That's the cut stems and all the fallen leaf debris you forget to gather up when you take out the diseased plants.)

When the spores germinate, the lesions begin to appear, and within 4-5 days, new spores are released to infect new leaves, stems, or flowers. These spores blow in the wind to new plants or in splashing water. The spores and disease are most active in cool, humid conditions, which is what we've got much of the time here in SF.

So if you have seen this disease on your fava bean plants, take those plants out as soon as you can. Take the whole plant out, roots, fallen leaves, everything. Do not compost it in your garden, though the SF Green Bin is generally OK for diseased plants, since their process is very hot and thorough. Do not save seed from these plants. It should be OK to eat the beans that aren't disfigured by any lesions. This fall, try to avoid planting favas in the same place you used last year if they were infected. Get fresh seed, and look for varieties that have shown resistance. (I will look for some--no idea where to find 'em yet. Send a comment in if you find some, please.)

Another web page says that this disease was first documented in California in 1998. It was found near the coast, no surprise, considering its adaptation to cool, damp weather.

I suppose that farmers who aren't farming organically use fungicides that organic farmers wouldn't use. What would I use? I notice that the label of Serenade fungicide includes both "vegetables" and the plant disease genus "botrytis," so I think I'd give it a try.

Serenade, which is permitted to organic farmers, has as its active ingredient the common soil bacterium Bacillus subtilis. This organism colonizes the plant surface, I've been told, preventing other microorganismns from getting a spore-hold. You spray it on plants weekly. They recommend spraying on a small part of the plant first to see if it will harm the plant. You can apply it up to the day of harvest. (This is not a recommendation, just my thoughts on what I might try and why. As with any pesticide, read the label for yourself before you buy, mix or use it and follow the directions carefully)

However, as with any plant pest, it would be quite unwise to try to control it using a chemical. If you have seen this disease, I repeat: Get those plants out of your garden. Rotate to a new site for favas. Don't save seed. Help me locate some resistant varieties. Then, if you had this disease this year, and have planted fresh seed in a new garden location, next fall, you might try spraying the plants when they are young, before any disease has appeared, to try to prevent an outbreak.

By the way, our favas have not had this disease, I am happy to report, and we've been eating young fava bean pods, when the seeds are still small, roasted in the oven according to a recipe that appeared in the SF Chronicle a few weeks ago. You roll them in olive oil, add salt and pepper, and roast at 450 degrees for about 25 minutes. Sprinkle with more salt, eat pods and all. Serve as a side dish or just before a meal. You may have to pull strings off the pods, but they sure are good!


Tomato Trials 2011

That mean old late blight strikes every year in my community garden and when I am foolish enough to think I can grow tomatoes at City College, so I am still on the lookout for a late blight resistant variety or two. Inland gardeners may escape this nasty disease, but it is thriving in cooler gardens near the coast.

Two years ago, in a trial reported in this blog, I grew several varieties that "someone" on the web said resisted late blight where they garden. Not a very scientific choice, but for several years, I tried the ones that wholesale seed companies and universities have been developing for resistance and none of those worked, so I was ready to try anything.

As a review, tomato late blight, which is the same as potato late blight, and which caused the Irish potato famine, is not soil borne, but carried by aerial spores from infected plants. It appears rather late (as in late blight) in the season. There are dark brown lesions on stems and leaves, followed by general collapse of the plants.Here are a couple of photos of plants with symptoms:

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The fruit may start to show the greasy brown coloration near the stem while it is stil green, or after it ripens. This may spread to whole fruits. In any case, fruit on infected plants ripens poorly and isn't sweet.
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The one variety that has been on the market for several years is 'Legend'. In my trials, it was the first to die. Here is the miserable dead plant of 'Legend' in 2009:

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Of the others I tried in 2009, my best plants were 'Juliet', which now is sold with a notation that it has some resistance to "Blight." (Not very informative, since there is also an early blight, a disease much more common in the Eastern US, but an entirely different disease.) Here is 'Juliet' in 2009:

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Although 'Juliet' had a touch of late blight, it produced a huge crop of these plum-type fruits--bigger than a cherry tomato, but smaller than a standard paste tomato. They were, however, perfect for the Broiled Tomatoes with Herbs and Cheese recipe I printed in Golden Gate Gardening.

In the past couple of years, late blight has been appearing on the East Coast as well as in the West. A few more supposedly resistant varieties have appeared, and I am trying 4 new ones:

Plum Regal F1 (Salsa/Sauce/Drying) 68 days

Golden Sweet F1 (Yellow Grape) 60 days

Mountain Magic F1 (Red, tall vine) 70 days

Defiant PHR F1 (Red, short vine) 70 days

So, I got them all from Johnny's Seeds, who may or may not have seeds of them left this year. They are all hybrids, and all relatively early. (The number of days doesn't count the 6 weeks or so to grow transplants, but anything under 75 is reasonably early.) The one I am most hopeful for is 'Defiant', since it has a formal "PHR" after the name, stands for "Phytopthora Resistant". (Phytopthora is the scientific genus name of the late blight fungus.) 'Defiant' is also said to resist 2 strains of the disease, so maybe it resists the strain we have while others didn't?

The plants will be potted up this week, planted out in May in one or possibly several San Francisco test sites. Stay tuned!