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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.



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Pam Peirce

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.

Jack Kenton

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.


I just bought pierces book. Love watsonia

Pam Peirce

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?

Katie Thorsnson

Isn't California's climate similar to Florida's?

Katie Thorsnson

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?

Ruth S.

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!

Pam Peirce

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.

Darlene Roelofsen

Hi Pam,

I'm from South Africa and love these indigenous beauties. What wonderful photos, and such healthy specimens!

Kind regards,


Pam Peirce

Hi Tracy,

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!

Tracey Novak-Marin


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?

Marge Mitchell

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!

Pam Peirce

Hi Irene,

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.



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