Small but mighty and, despite its name, not a grass, the premium forb S. campestre is a diminutive member of the Iridaceae (Iris Family). This perennial plant punctuates garden plantings with brilliant blue flowers that only open on sunny days. It thrives in both loam and sandy soils, provided the site is full-sun and well drained. It grows in tufts, typically no taller than 8-12 inches. when several plants are massed and allowed to spread, it creates a stunning, pale-blue green island It’s a hardy plant with no pest and disease issue of note.
Seedling Stage
In the wild and garden, S. campestre seeds have strong dormancy and require cold stratification. Gardeners should sow seeds in autumn on bare soil (do not bury deeply) or pre-treat them with 60–90 days of cold, moist stratification. When planted outdoors in fall, seeds naturally experience winter cold; if planting in spring, mix seeds with moist sand and refrigerate (4°C) for ~60 days before sowing. After stratification, keep the seedbed lightly moist. Germination typically begins in early spring (April–May) and can take 4–6 weeks.
First Signs of Growth
Young leaves are slender, stiff, and grasslike. Healthy seedlings form small upright tufts of green leaves a few inches tall (much like tiny iris leaves).
Early Growth
Over summer, each seedling develops a fan of narrow leaves. Plants form tight clumps up to roughly 6–12 inches tall with leaves up to ~10 inches long Growth is slow; you will see the clump gradually widen via short rhizomes or offsets. Optimal conditions are full sun (or very light shade) and a gritty, well-drained soil. Once established, S. campestre tolerates drought well but seedlings should be watered moderately until the clump is vigorous. Avoid heavy shade or moist, compacted soils, which can stunt growth.
Indicators of Health: Lush green leaves (no yellowing or wilt) indicate good health. Clumps should remain tight; overly sparse growth may mean poor light or soil.
Care: Weed competition should be minimal; Division is seldom needed, but clumps can be split in early spring or after flowering if crowded
The characteristic blue-eyed grass flower is small but eye-catching in spring. In mid to late spring (typically April–June), mature plants send up unbranched flower stalks (about as tall as the leaves) topped with 2–6 star-shaped flowers. Each flower is ~½–1 inch across, with six tepals pale blue to white and a bright yellow center. Flowers open in morning light and often close by afternoon. This early bloom attracts bees and other pollinators.
Garden Tips: Provide full sun for best bloom. Allow flowers to open fully (avoid overhead watering that breaks blossoms). Spent blooms can be deadheaded if you wish to tidy the plant or limit reseeding but leaving them on will naturally set seed.
Timing: Flowers usually appear in their first spring of maturity. In nature on the prairie, blooming peaks in May.
A variety of flowers and grasses play well with S. campestre. Consider little bluestem, side-oats grama, prairie dropseed, blazing star, prairie clover, and golden Alexanders.