Northwest Gardeners Benefit From Nature's Bounty
Gardeners know that joy comes disguised as gifts from the garden: homegrown tomatoes, a bouquet of cut blossoms, and free plants produced by the garden's self-seeders. Plants that seed their bounty throughout the garden provide more than bonus seedlings. They fill empty spaces with beauty, thwarting weeds' attempts at a foothold. The discovery of new green treasures yields thrills each spring. Nature-created vignettes spark creativity and often envy over combinations we wish we could claim as our own. Surplus plants become presents to fellow gardeners. Here are four self-sowing plants that I enjoy growing in my garden just outside of Portland, Oregon.
Satin flower sends up early-summer blooms
Sisyrinchium striatum, syn. Phaiophleps nigricans
Sunset Zones: 4-9, 14-24.
USDA Hardiness Zones: 7 to 10.
Size: 24 to 32 inches tall and 18 to 24 inches wide.
In early summer, multiple spikes of small, pale yellow blooms with dark-yellow centers and faint purple stripes rise above gray-green foliage. Satin flower is a clump-forming evergreen that requires little care other than tidying the foliage in spring and deadheading the flowers for prolonged bloom. It does best in well-drained, poor to moderately fertile soils in full sun and it is drought tolerant once established. Seedlings are fast growing and bloom in the second year; unwanted plants can easily be removed.
Hardy begonia offers dramatic foliage for shade
Begonia grandis ssp. evansiana
Sunset zones: 3-24.
USDA Hardiness Zones: 6 to 9.
Size: 2 feet tall and 12 to 18 inches wide.
This begonia's dramatic, heart-shaped, olive-green foliage brightens in dappled sunlight but its red veining and claret-stained undersides steal the show when backlit. Pendant clusters of satin pink flowers are a welcome treat from midsummer until frost in shady borders. Give plants rich, moist soil and keep them out of hot afternoon sun. In fall, tiny bulbils form in the leaf axils; harvest or allow them to drop to steadily increase clump size. New plants will bloom in the second year and excess seedlings can easily be removed.
Masterworts shine in rich, organic soils
Astrantia major and cvs.
Sunset zones: 1-9, 14-24.
USDA Hardiness Zones: 4 to 8.
Size: 18 to 36 inches tall and 12 to 18 inches wide.
Ascending like diminutive fireworks above deeply lobed foliage from May through summer, the flowers of masterworts bloom in shades of creamy white, pale pink, green, or purple-red. Plants are at home in moist, humus-rich, well-drained soil in dappled shade. Deadheading will encourage more blooms, just be sure to leave a few flowers behind for self-sowing. Because masterworts interbreed easily, species, subspecies, and varieties are more likely to seed true if isolated from other forms. Cultivars may not seed true. Seedlings can take two to four years to flower.
Annual cosmos thrives in lean soils
Cosmos bipinnatus and cvs.
Size: 12 to 60 inches tall and 12 to 18 inches wide.
White-, pink-, lavender-, or crimson-petaled daisy-like flowers wave airily above finely divided leaves on this cut-and-come-again summer bloomer. Cosmos will self-sow in mulch-free areas and produce new flowering plants within the year. Seedlings may not come true to form, particularly fancy-petaled cultivars. Plants prefer full sun and well-drained, lean soil, and should be watered infrequently but deeply. For best results, thin seedlings 10 to 15 inches apart. Cosmos rarely requires fertilizer except in sandy soils. Tall varieties grown in rich soils may need staking.
- Top and third photo: Begonia grandis photographed by Debbie Teashon in her Kingston garden.
- Second photo: Sisyrinchium striatum photographed by Lisa Albert in author's garden.
- Fourth photo: Astrantia major photographed by Lisa Albert in author's garden.
- Bottom photo: Cosmos bipinnatus photographed by Debbie Teashon in her Kingston garden.
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