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September 2006
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Warm Fall Nights in San Francisco

San Francisco is having a warm spell, our last of the summer warm period, when the ocean has warmed up and the fog bank is staying away. The wind on our street is blowing the urban debris from east to west, instead of the usual west to east. The nights are even warm, which is quite rare. (That song about a warm summer night in San Francisco is about the exception, not the rule.) Last night I was helping students make compost into the dusk in only a tee shirt with a flannel shirt over it and I was quite comfortable.

The warm period is running a bit late this year, after an early rain left us sure that we would have no more summer. Now I am rooting for the warmth and wishing for cold and rain simultaneously. If it would rain, the leafminers would stop molesting my Swiss chard, and I could transplant kale, arugula, and other fall and winter greens without worrying that they will wilt in the sun. But if it stays warm, my late-planted annual mallow will soon be covered with silky pink or white blooms and the cucumbers will go on bearing for a few more weeks.

The good news is that there will be benefits in either course of the weather. So I am out tending the plants, using the balmy nights to hunt the young snails that have grown from this summer's breeding, harvesting small but delicious cucumbers, and taking what comes.

The apples ripened in mid-October, exactly on schedule. It's a small harvest this year, but as sweet and crunchy as ever, with no sign of the apple scab that I had last year. That is because, though we had late rains this past spring, they stopped before our tree bloomed and leafed out. (The first year we moved in, I was sure the poor tree was dead, since it had bare limbs until well into April, but we are used to its late blooming ways now.) Last year's scab problem occured because the rains came weekly through June and caught us by surprise. I thought they were all over, and kept thinking so until it was too late to spray sulfur. Ah, how these warm days bring out the fragrance of the apples! I have been reading about new ways the food industry uses to preserve apples for out-of-season sale, while I am savoring my in-season apples.

Creative Plant Staking

The usual instructions about staking plants refer to tying the plants to stakes to keep them from falling over. We might stake a gladious or a foxglove so it won't lean, for example. I do this, but I have been noticing how often I stake a plant for other reasons.

Yesterday I staked a little annual bush morning glory (Convolvulus tricolor) to keep the wind from blowing it over and breaking it. It is in a container, and consists of about 5 branches that start near the ground. In a strong wind, it was waving back and forth, threatening to break.

Today I staked a fuchsia-flowered gooseberry (Ribes speciosum) to keep one of its thorny branches from reaching into the path and stabbing somebodies knees. Actually it was the second time I had staked that branch back. I often stake once, and then, in a couple of weeks, restake, with more pressure than the first time. The plant might break if you do it all at once, but in two stages, you can do it.

Last week I staked a viper's bugloss (Echium vulgare 'Blue Bedder') to keep it from leaning onto a wee viola. I am always ready to referee between competing plants this way, staking one out of the way of another.

And all summer, I have been staking rose canes to make them take a better direction--for example, not reaching out over a lawn, not growing against another cane, not reaching into the neighboring rose. These are often twice-staking operations, since rose canes are rather stiff, and I don't want to break them. But by staking them sort of in the right direction once, then pulling the stake and resetting it to apply more pressure, I have gotten 5 poorly directed canes to straighen up and fly right.

Other gardeners must do this stuff, but you never read about it. Readers, have you been doing any creative plant staking lately?

Potting Mix Grew Mushrooms

The path to fine arugula may not be smooth

The tiny seedling arched its stem to push through the potting mix. It was still white, having not yet seen the sun, but I moved it to the bright windowsill in anticipation. But alas, it didn't turn green. Instead, the white nub emerged, revealing itself to be a tiny white mushroom. Soon there were more of them. The arugula and collard seedlings emerged, but remained stunted and with poor color. The mushrooms opened into tiny striped gray parasols and then collapsed. A new flush emerged. My seedlings languished.

Thus did I fail at my first attempt to grow the superior Cook's Garden arugula strain.

When I returned the half-used potting mix to the nursery, I brought along a flat of arugula sporting a mushroom or two for them to observe. The clerk opined that perhaps I had kept it too wet. I replied that there should not be live mushroom spores in bagged potting mix, period. He exchanged it for a (hopefully) mushroom-free bag, and wrote on the exchange form "grows mushrooms."

Now I know that there are seeding mixes made to start seedlings, and I use one at the college, in a large greenhouse, because I know it is less susceptible to problems caused by the inevitablely less attentive care than seeded flats would get in my window at home, 8 feet from my computer.

Seeding mix has smaller particles, and more air and water holding capacity than potting mix, and lacks fertilizer, which can encourage water molds and decay bacteria that can take hold in overwatered containers. I have always succeeded with potting mix at home, since I can pay careful attention to water here. I gave some thought to whether I had introduced mushrooms, but decided if I had introduced spores somehow, it wouldn't have been in all 6 flats, which had different histories before reuse.

So now I have some really nice 3-inch seedlings of the arugula in the ground outdoors and some tiny new ones in fresh, mushroom-free potting mix in the windowsill. One of these days I will get to harvest some of that arugula. Gardening is all about patience, right?

When I do, I plan to make my pasta and arugula special. I like the tang of raw arugula, but I also like the milder flavor it has when cooked, as in this dish. For each diner, I mix a cubic inch of soft goat cheese or feta cheese with water to make a smooth, creamy sauce. Then I boil some pasta and, at the same time, saute some onion in a little olive oil. When the onion is done, I add a bit of minced garlic and saute it for about 30 seconds. Then in goes a big bunch of arugula leaves, cut up coarsely. When the arugula is cooked, I add the cheese mixture, the pasta, salt, pepper, and a bit of grated Parmesan, toss it all and serve it hot.

Four O'Clocks in China!

My Golden Gate Gardener column in today's S.F. Chronicle ( answers a question about four o'clocks. The seed for the plants in question was brought from China, where it turns out these bright flowers are immensely popular.

The species is Mirabilis jalapa, a plant that is not known in the wild, but is believed to be native to Mexico. It is found in all of the former Aztec sites as well as places where the Spanish built colonial towns and is still a popular plant in Mexico and elsewhere in Central America.They are considered an "old garden flower" in this country.

It seems that the plant is also very popular in China, a fact I didn't know when I featured it in Wildly Successful Plants: Northern California. An exchange student brought some seeds here (which is probably illegal), and said they were common in her village. I am told they are grown as an annual where not hardy, and as a perennial where they are, just as they are here. (Now I am so curious to find out which other flowers are popular there.)

So the plant started in Mexico, went to Spain, and thence throughout Europe, then back to America, where Thomas Jefferson grew some in his garden, then accross America to California, while also probably coming up with those who came to California from Mexico. (The plants we photographed for the book came from Mexico as seeds in the pocket of a lady who was moving to Menlo Park.) And also, across Europe and into Asia? (Are they grown in Russia or India?) Or did they arrive with Europeans in China? Or? And then, back to California from China. 

There are more variations in the plants than I thought as well. The plants from China reach 4 to 6 feet tall, which I am told is typical of the species, while varieties from seed catalogs are shorter, maybe 2 feet tall. There are fragrant ones, such as the ones Jefferson grew beneath his window so the wind could waft the scent indoors on summer evenings, and ones with no scent. There are ones that truly open at 4 o'clock, and stay open at night for the pollinating night-flying moths, and ones that open in the morning and close at night.

The most popular varieties are usually the ones with "broken colors," that is, ones that have flowers streaked and splashed with 2 colors, along with solid color flowers of both colors, on the same plant. These can be any combination of white, yellow, or magenta.

Some would consider them too common to grow, but they can be glorious, big shrubby plants, covered with bright flowers for a couple of months, favored by hummingbirds, perhaps scented. They can make a nice summer hedge.

The caution is that they can reseed, but they may not. If they do, and the seedling is in the crack of pavement or brickwork, take it out, since the big tuberous root will be hard to remove or kill in this situation.

A rose cane may die--should you worry?

In last week's column for the S.F. Chronicle (September 27, 2006), I wrote about the fact that roses are prone to occasional dying canes and that this can be caused by many different stresses. Cold winters can cause canes to die, but so can botrytis (gray mold), powdery mildew, black spot disease, soil that is too wet, too much fertilizer. Less commonly, there are insects borers or canker diseases that can kill canes. Many cane deaths start with an injury that isn't lethal in itself, but allows a fungus in that kills the cane. And these fungi aren't ones that cause a specific disease, just opportunistic fungi that attack weakened plant tissue. And the injury could be just normal deadheading or pruning.

With all of these causes, one begins to feel it must be the exception that rose canes survive, and yet, survive they mostly do. The bottom line is that a few may die, you cut them out and try to figure out if you can do anything else to prevent it from happening again.

I think that learning to grow plants is often a process of learning when to worry and how much to worry. New gardeners often worry when a single leaf turns yellow, a single twig dies. It is right to worry when rose canes die, but, like an occasional yellow leaf, it might not have an underlying cause you could have anticipated, or, it might.

Read my columns on You can find them by searching for my name (Pam Peirce) or for a specific topic.