Easy Pleasing Clarkias!

By Annie Hayes
Gardener-in-Chief

One Fall a large pine tree fell over into my backyard, discouraging me from going out to weed and turn over my soil as I usually do at that time of year. The tree was finally removed in the Spring, and when I went out into my garden again I was tickled to see Clarkia seedlings carpeting almost half the garden. I find it pretty surprising how rarely I see our native Clarkias growing in the Bay Area, even in native gardens. With their showy blooms over such a long season, easy-going temperament, and willingness to forego Summer water, you’d think they’d be far more popular. And being deer resistant, tolerant of heat and seaside conditions—what more could you ask? Cut flowers? Clarkias are some of the prettiest and longest lasting cut flowers you can grow.

Maybe folks are put off by the sad, dwarfed version of our lovely “Farewell-to-Spring” (Clarkia amoena) you sometimes find at garden centers and box stores. Sold as “Godetia” or Godetia grandiflora, bred to bloom at an unnatural height of 6″ tall—the better to fit between delivery truck shelves—and almost always sprayed with growth regulators, this makes a poor representative for the genus. Left alone, “Farewell-to-Spring” naturally grows to at least 30″ tall. How sad to see the crowded cluster of blooms bunched awkwardly on top of stiff 6″ stems, with nowhere to go and nothing to do. Since the stems cannot grow upwards, these poor plants will soon deteriorate. But then again, maybe most gardeners don’t even realize that these Godetias are California natives; with their bizarre stunted form, they surely don’t look like wildflowers.

Natural Clarkias are highly rewarding in almost any garden. True to their common name of “Farewell-to-Spring”, Clarkias deliver a mass of blooms just as most other Spring-flowering native annuals are fading away. Because of this, they are valuable for filling in that flowering lull after the peak of Spring bloom, and, in decent soil with some Summer water, they’ll continue blooming until Fall. Super easy to grow and a nice solution for adding excitement to new gardens with lots of bare earth, Clarkias are one of those plants that make you feel ever so successful with very little effort. Plus, they attract bees and butterflies. Birds love the seeds, which freely self-sow for new showy patches next year.

About that volunteer overabundance? Not to worry, they are a cinch to remove if needed, sliding right out of the soil with the slightest tug. But crowded patches of seedlings are not a bad thing in the case of Clarkias—they don’t seem to mind being crowded, and if you leave one of these spots of dense seedlings alone, they’ll provide a wild patch of brilliant color without any thinning.

Got clay? Most Clarkias thrive and reseed themselves in sandy, clayish, and infertile soils, happiest when there is some drainage. I’ve watched a patch of elegant Clarkia (C. unguiculata) self-sow and return for years on someone’s partly shady, untilled and untended clay hillside by their house in Kensington in the San Francisco Bay Area.

Here at the nursery we don’t have a garden devoted to only native plants. Though Clarkias are beautiful planted in groups or even singly, free to stretch out and reach their natural form and glory, I mix our most popular species into my cottage-y gardens with great success. They make perfect long-blooming fillers that keep pumping out blooms as other nearby plants go in and out of flower. (Cut-and-bloom tip: Clarkias bloom from the bottom upward along the stem; when cutting stems for cut flowers, always cut below the lowest bloom to encourage the plant to send up a new shoot and bloom again.)

Our demonstration gardens have rich, loamy soil and are watered frequently when it’s not raining. Clarkias are so adaptable they don’t mind the luxurious soil and regular watering a bit, and they are probably more floriferous over a longer season for it. Almost all Clarkias prefer a sunny position with at least six hours of full sun along the coast and coexist happily in mixed plantings, native or otherwise. In my experience, they are most glorious when not overshadowed by taller plants. They are quite wonderful and easy in containers too, as long as the pot is large enough. I love seeing them in meadow-y situations popping their blooms up above shorter grasses as they will continue to bloom even after the grass turns golden.

We begin sowing our Clarkias in December and sow seeds every two weeks until April, but you can toss seeds out onto the ground in the Fall along the coast. Successive sowings from Winter through Spring would give you the longest season of good-looking plants and plentiful bloom. In colder zones and at high elevations, you should wait until April or May for sowing the seeds.

There are 40 species and many subspecies and varieties of Clarkia, all but one native to the western United States; nearly every species is found somewhere in California. Though we’ve offered many in the past, we usually offer about eight varieties each year. Here are some of our most popular ones:

Clarkia speciosa ssp. immaculata “Pismo Clarkia”

Absolutely stunning trailing over the edge of a raised bed. Rare, endangered, and endemic to California, “Pismo Clarkia” is native to the sandy hills east of Pismo Beach south to Santa Maria. I often plant this eye-catching Clarkia right near the entrance to the nursery to start visitors off with a thrill. Most folks have never seen it before and practically everyone asks, “What is that?” I usually plant it out in full sun from 4″ pots from February to April, grouped three together on twelve-inch centers, side dressing with an inch or less of compost after planting. By mid-May, I have a compact, bushy mound about 14″ tall and 3′ across, almost covered in beautiful 2″, sky-facing, silky magenta blooms held on short stems, each cup-shaped flower bearing a snowy white center. Full bloom lasts from mid-May through Summer and you can extend the bloom until September by deadheading. Since it’s native to sandy soils and our beds are so rich, I always plant these on the edge of a bed to ensure extra drainage and add lava rock before planting, as well. It’s also happy as a clam in a largish container, 15- to 20-gallon size, as the blooms spill beautifully over the edge and appreciate the drainage a container offers. Lovely with white California poppies and Lupinus arboreus.

Clarkia amoena aka Godetia grandiflora “Farewell-to-Spring”

Like the others, C. amoena makes a terrific cut flower; this is the species you often see in florists’ bouquets. 1.25″, cup-shaped, sometimes wavy blooms are held singly or in clusters of up to 6″ across, depending on the variety. They are the latest to bloom in our gardens, beginning in late May to June here by the San Francisco Bay, and are usually considered the showiest of all Clarkias with their vivid colors and prolific bloom. There are lots of selections in the nursery trade with flower colors ranging from pink, red, magenta, and salmon to white, many offering vivid contrasting patterns, edging, or blotches. Generally growing from 30″ to 3′ tall and wide, some of the varieties bred especially for cut flowers can look a little awkward in the garden, particularly in rich soil, with their large clusters atop long, upright, stiff stems (great for cutting). They look best when massed or mixed with other plants of the same height. Container plants are nice for providing cut flowers, though I would probably tip-pinch the main stem while young to encourage side growth and keep them from bending over under the weight of their flower clusters. A cinch to grow in sandy to clayish or good compost-enhanced garden soil, “Farewell-to-Spring” is tolerant of part-day shade, but along the foggy coast I recommend you plant it in full sun, as it can get floppy. Shorter varieties growing to about 18″ tall can be obtained from seed catalogs, but I have yet to try them with my aversion to dwarfed anything!

‘Aurora’, our most popular variety of C. amoena, bears large, gorgeous clusters of wavy peach blossoms edged in white, fantastic in flower arrangements. Up to 3′ tall and multi-branched, it can be one of those “stiff leggers” in the garden. The large terminal clusters may cause the branches to bend over, especially when grown in less than 6 hours of sun. Tip-pinch when young for better form.

Clarkia rubicunda ssp. blasdalei “Ruby Chalice Clarkia”

For sheer exuberance of bloom and usefulness in the garden, I think this is currently my favorite Clarkia. Primarily native to the Bay Area counties, with smaller populations in San Luis Obispo, Monterey, and Humboldt counties, “Ruby Chalice” is another easy, beautiful, long-blooming showstopper for almost any garden. In our gardens, again with rich soil and Summer water, much-branched slender stems and linear leaves create an attractive bushy form 30″ to 3′ tall and 30″ across. From May thru Fall it’s quite a sight, brimming with countless 2″ lavender, cup-shaped, upright blooms ornamented with a central bright cherry-red blotch. I plant three or four seedlings about 15″ apart for a dazzling Mother’s Day display 4-5′ in diameter. Self-sown seedlings popping up the next season with little or no thinning produce the same effect. Adaptable to a wide range of soils and conditions including coastal salt spray, this is another Clarkia that can tolerate a bit of shade, especially further away from the coast.

Clarkia unguiculata “Elegant Clarkia”

An excellent, garden-worthy Clarkia endemic to California. It’s easy, fast-growing, and tolerant of infertile and clayish soils. If you have hardpan clay, add a bit of organic material for drainage and better performance. Although it’s available in colors from white to pink, salmon, and violet, we’ve been unable to source any colors other than salmon in the past few years. Spidery, pinwheel-shaped single blooms about two inches across are well displayed on upright branching wine-red stems from 30″ to 4′ tall. Beginning at the base, the flowers work their way up the stems, creating a mass of what looks like brightly colored orchids or butterflies that sway in the breeze. You can grow it in front or mid-bed, massed or singly—all ways are highly effective. It’s also a great choice for new gardeners as it fills in bare patches quickly, providing foliage, texture, and lots of color. “Elegant Clarkia” is possibly the most tolerant of partial shade, and some gardeners tip-pinch them while young to promote a shorter, bushier plant where there is less light. Like all Clarkias, it requires no summer water, but an occasional drink along with dead-heading certainly lengthens the bloom season. Easily grown in containers, 20-gallon size for best show, you can keep it coming at its peak with successive sowings.

In native gardens the salmon-flowered selection ‘Salmon Princess’ makes a winning partner for Salvia clevelandii ‘Winifred Gilman’ or Verbena lilacina ‘De La Mina’. In our mixed gardens, I love it combined with equally long-blooming Dahlia ‘Softie’, Petunia integrifolia, and Verbena bonariensis. Like all Clarkias, it’s incredibly long lasting as a cut flower, up to three weeks. It’s easy to find mixed color seeds, and, when sown all together, the plants make a lovely and cheery sight. Double forms are sometimes available from seed.

Clarkia concinna ‘Pink Ribbons’

‘Pink Ribbons’ is a named cultivar of “Red Ribbons”, the common name for C. concinna. Billowing over the edge of a bed or container, the flowers of ‘Pink Ribbons’ look like a mass of silky, brightest rose butterflies gathering over the bushy, slightly sprawling 12″ x 18″ mound of slender foliage and shiny red stems. Up close the 1.25″ flowers resemble flaring pinwheels or fans, with each of the four widely spaced petals trilobed in shape. Endemic almost entirely to Northern California, this delightful Clarkia is one of the earliest bloomers beginning in April and lasting thru July. I like to plant it near the front of a bed where you can enjoy the butterflies close up.

Contrasting beautifully against dark foliage like with Heuchera ‘Melting Fire’, the blooms add a bright and cheery highlight to ‘Apricot Chiffon’ “California Poppies” and “Baby Blue Eyes” (Nemophila menziesii). Tolerant of less than perfect soil, it will be showiest in loamy garden soil. I’ve used it in both part shade and full sun here in foggy Richmond, and it worked well in both situations with longer and more profuse bloom in full sun.

We have grown and offered quite a few more species that have been less popular with visitors, some with flowers too small to be loved and taken home, others, like the charming and deliciously fragrant Clarkia breweri, a bit too difficult for newer gardeners. I’m endlessly fascinated though and would love to access seed and grow so many more. The California Native Plant Society’s Calscape website has a good list of Clarkias with photos and distribution maps of each species listed. It’s a handy tool for guiding you to many species currently found only in the wild. With all the rain we’ve had here in the Bay Area, this year the show should be outstanding!