Watsonias--Wildly Successful Plant of Late Spring
May 22, 2012
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.
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.
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.
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.
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.
I see white watsonias in gardens along the Oregon coast. Fortunately, the gardens at my grandma's and great grandma's homes on the coast have them and we share them among family members in the Portland metro region. This is my first year planting them and hope they thrive in my south facing, sunny backyard!
Posted by: BriMar503 | May 12, 2023 at 07:40 PM
Do you know where I can purchase some lavender Watsonia bulbs.
I live in the Bay Area and do not see them in garden centers and haven't been able to find a mail order place online to order them. Thanks
Posted by: Sharon B. | December 05, 2021 at 04:40 PM
I am in Cornwall, U.K. and most year we manage to grow(mostly outside) a range of Watsonia from January through to mid-summer. We find most of them easy to propagate from seed. We have W. Knysnana, W wilmaniae, W. borbonica ‘Arderne’s White’ , W. Tresco Hybid, W. Dart Sea Trout, W. lacata and many more. We have recently added W. Marginata which is flowering and W. fourcadei which is about to flower. They grow pretty well for us and I don’t know why more people don’t grow them in the U.K.
Posted by: Martin Pallett | June 13, 2021 at 01:21 PM
Two readers have wondered where to get white Watsonias, and I am sorry to say I don't know. All I can say, once again, is to watch for them In bloom in spring and ask for corms from the gardener who is growing them when the plants are dormant. The corms multiply every year, so a gardener often wants to share them. I will look in catalogs, but I suspect if they were readily available I or you would have noticed a source for them by now. Maybe it would help to write bulb suppliers and tell them how much you love Watsonia. I get the impression they are out of fashion, but I suspect the suppliers have stock of them growing somewhere.
Posted by: Pam Peirce | April 20, 2021 at 01:35 PM
I have loved reading your articles particularly the one on watsonia bulbs. I am in Australia however and M really keen to find some white watsonia bulbs but not having any luck I'm afraid. Any suggestions would be greatly welcomed. Cheers and happy gardening Maggie
Posted by: Maggie Minogue | April 18, 2021 at 04:05 PM
Unfortunately, I don't know a source for white-flowered Watsonia corms. I would try all the bulb sources I could find. Or, if you see them blooming, ask the person in whose garden they are planted if they will share some with you when the plants are dormant in summer.
Posted by: Pam Peirce | February 04, 2021 at 04:19 PM
Hello! I have been searching for the white watsonia bulbs where can I purchase them?
Posted by: Maria Villamor | November 29, 2020 at 09:20 AM
Hello! I have been in search of Watsonia Borbonica (I would love white and pink) corms for over the past year, and can not find any to save my life! Does anyone know where I could find some, or would anyone be willing to share? I think they are beautiful! Thank you!
Posted by: Heather Walters | May 11, 2019 at 03:45 PM
It is very mysterious to me why Watsonias would bloom in yellow or orange. I have seen peach-colored Watsonias, but not yellow. My best guess is that your planting has somehow become invaded by Chasmanthe, another South African bulb, which has similar leaves, but smaller flowers in yellow or orange. Please check out the appearance of Chasmanthe vs. Watsonia and see if I'm right. Chasmanthe also most often blooms earlier than Watsonia. It is blooming now, March 10, 2019, in San Francisco, whereas Watsonia is not yet in bloom. If it is Chasmanthe, and you don't want it, you will need to remove the Chasmanthe corms, best done while they are in bloom, so you can tell them from the similar-looking Watsonia corms, though there are subtle differences in the leaves if you look closely.
Posted by: Pam Peirce | March 11, 2019 at 06:22 PM
I have had white flowering watsonias for years but last year they started mysteriously flowering in yellow and orange with many fewer white. The white are so much prettier than the ubiquitous yellow and orange. Any idea why this happening? I live in the SF Bar Area are the are planted in the front of my house.
Posted by: Mary Anne Morgan | March 11, 2019 at 05:00 PM
I am thrilled to discover what these beauties are called. We just bought a home in No San Diego County, which backs up to Camp Pendleton, and all of a sudden these flower spikes started to come up. They are everywhere, along the fence line , under trees . Thousands, if not hundreds! I thought they were glads, but now thin closed flower spikes are appearing. They look in the early stage to be white, red, and lavender. The home was built in the 60's, so I think they have been here many years. Can't wait for bloom!!!
Posted by: cheryl suddaby | December 28, 2018 at 01:47 PM
Cutting back the flowering stems after they bloom is just standard gardening maintenance practice. I suppose it lets the plants store more energy in their corms, so they can grow well the following year. If you leave the stalks on until seeds form, some of the energy of the plant goes into making the seeds. Most gardeners cut back unless they want to save seeds. (Seeds of bulb-forming plants can certainly be saved and grown, though they will require several years to make a plant big enough to bloom, so most gardeners just divide the bulbs, corms, or whatever, instead.) But if you want to look at the spent flower stems longer, little harm in that.
Posted by: Pam Peirce | June 25, 2018 at 10:38 PM
Why should I cut the stalks so early? The stalks are still beautiful even they after they flower, and people think they are about to bloom. Once you cut the stalks there is a bare spot in the garden. I’ve haven’t cut my stalks this year and I’m really happy I haven’t. Is there a reason I should have? Of course, I will cut them sometime before the leaves start to die back. I look forward to hearing your answer! Thanks!
Posted by: Jim | June 05, 2018 at 03:31 PM
Jack, I am not sure what you have said in your comment. Did the watsonias you had at first bloom, and then have some flowers that were pink rather than what the others were? (If so, what color were the rest?) Why they aren't flowering now is a mystery to me. While it is true that plants bloom better when phosphorus is not lacking in soil, Watsonias originated in a place with very poor soil, so generally don't need fertilizer. My family had blooming watsonias south of L..A. , so I know they don't need more winter cold than your location in Riverside could provide. Are they getting winter sun? That would probably help.
Posted by: Pam Peirce | June 12, 2017 at 01:22 PM
I had a lot of Watsonia plants in my El Segundo yard (near L.A.) and was surprised when a couple of them had pink flowers one time. Now I've moved 15 or 20 to where I am near Riverside, CA. They make great leaves, but not even a hint of a flower.
I see something about flowers needing phosphorus. As a senior citizen, that is a new one on me.
Posted by: Jack Kenton | April 28, 2017 at 10:01 AM
I just bought pierces book. Love watsonia
Posted by: Karl | September 24, 2016 at 11:03 AM
The subtropical climates of Florida are not like the one we have here in California in that we have a long dry summer, whereas Florida has a rainy and humid summer. The name for California's climate is mediterranean, because it is similar to climate of the area around the Mediterranean Sea. The other parts of the world with this climate are Central Coastal Chili, Southwest Australia, and the southwestern tip of South Africa, which is called the Cape Region. Here in California we seek out plants from those regions because they thrive where summer is dry.
Watsonias are from the Cape Region of South Africa, so they are well-adapted here, but I do not think they would do well In Florida. I think the corms would rot in Florida's wet summer. Maybe they would grow one year, if planted in fall, to bloom in spring. Then maybe if you dug up the corms and stored them in a dry place, you could replant them in fall. I don't know. Has anyone tried this?
Posted by: Pam Peirce | March 28, 2016 at 02:43 PM
Isn't California's climate similar to Florida's?
Posted by: Katie Thorsnson | March 23, 2016 at 02:18 PM
I absolutely love these plants and I've always wanted to have them in my backyard. You are in California it sounds like, will these beautiful plants grow well in Florida?
Posted by: Katie Thorsnson | March 23, 2016 at 02:14 PM
I would Love to get my grubby paws on a variety of Watsonia Corms..
Anyone want to sell me some? I'd love the beautiful Pink, White or orange ones.i've seen some orange and yellow ones that are about 2-2 1/2 ft tall and white ones that were 6-8 ft. tall and pink ones that were about 4-5 feet tall..But everywhere I look they are sold out or only for sale in Africa.
All help appreciated.
Thanks so much!
Posted by: Ruth S. | March 24, 2015 at 07:33 PM
Thank you Darlene! Watsonias aren't as popular here as they once were, but they deserve more attention, especially with our current drought. We do love many of your South African plants.
Posted by: Pam Peirce | February 15, 2014 at 12:21 PM
I'm from South Africa and love these indigenous beauties. What wonderful photos, and such healthy specimens!
Posted by: Darlene Roelofsen | January 17, 2014 at 12:49 AM
I bought the red watsonia bulbs several years ago from Sloat Nursery in San Francisco. They didn't have a variety name. They came from Nurseryman's Exchange, so I spoke to that wholesale nursery, in part because I was including watsonia in my book, Wildly Successful Plants and wanted to see if I could find out what the parents of the hybrid might have been. Unfortunately, they replied that it was one of several hybrids made long ago, and the information about parentage had been lost. Mine are in bud right now, and it looks as though it will be a good year for the plants!
Posted by: Pam Peirce | April 11, 2013 at 11:32 AM
The red colored Watsonia in the first 2 photos is very pretty. Do you have more specific information as to the name of the hybrid or the nursery you purchased it from?
Posted by: Tracey Novak-Marin | April 04, 2013 at 06:19 AM
I have had a Watsonia plant for three years now. It has tripled in size but has never had any flowers. It is the evergreen type and it gets the afternoon sun. I regularly water with sprinklers. I am now thinking that they should be transplanted!
Posted by: Marge Mitchell | November 18, 2012 at 05:46 AM
Go ahead and plant them. Plant them 4 inches deep. If they are alive, they should be fine. It is OK if they are growing, though it may stunt them a bit the first year not to have roots when they began to grow. Some may not bloom the first year because of this. Assuming they survive, they should be able to bloom normally by the second year.
Posted by: Pam Peirce | November 07, 2012 at 12:21 PM
I HAVE A LOT OF WATSONIA BULBS THAT WEREN'T PLANTED IN SUMMER.
IS IT TOO LATE TO PLANT THEM TODAY (OCT 3)?
IF I CAN'T PLANT THEM NOW, CAN I STORE THEM AWAY FOR NEXT
Posted by: IRENE KASPER OF SANTA BARBARA, CA | October 04, 2012 at 12:02 PM