About Globe Thistle
Blue Globe Thistle is a striking, clump-forming perennial prized for its metallic-blue, globe-shaped flowers and silvery-green, deeply lobed foliage. It thrives in poor, dry soils where many other plants fail and attracts bees and butterflies all summer long. Its unique texture and color make it ideal for borders, cut flower gardens, and pollinator plantings. Hardy in Zones 3 through 9.
When to Plant Globe Thistle Roots
Plant dormant roots outdoors in spring after the danger of frost has passed and the soil is workable. This allows the roots to strongly establish themselves before heavy growth in summer.
Where to Plant Globe Thistle Roots
Choose a full sun location in moderately fertile, well-draining, sandy soil for best flowering and stable, compact growth. When Globe Thistle grows in partially shaded areas or in clay or overly rich soils it can become leggy and produce fewer blooms.
How to Plant Globe Thistle Roots
Loosen soil 10 to 12 inches deep to improve drainage and root penetration. Plant roots one to two inches below the soil surface, positioning the crown just beneath the top layer of soil. Space roots 18 to 24 inches apart to allow ample airflow and room for mature clumps. Water thoroughly after planting and keep the soil lightly moist until growth begins.
If growing in a container, select a deep container that is at least 12 inches tall and filled with a gritty, well-draining mix. Globe thistle adapts well to large pots when drainage is excellent.
How to Care for Globe Thistle
Globe Thistle has low water needs once established. Allow the soil to dry between waterings as overwatering may cause root rot. Fertilizing is not necessary, but it can tolerate a light, balanced fertilizer applied in spring if the soil is particularly poor. Excess nutrients can lead to weak stems.
Cut back spent flowers to encourage extended blooming or leave seed heads for fall and winter interest. The perfectly round, steel-blue flower heads mature into bristly, grayish-brown seed balls where goldfinches, chickadees, and other small seed-eaters love to perch on and feed. Cut stems back in early spring when new growth begins.
No special protection is needed throughout the winter. In areas with wet winters, ensure excellent drainage to prevent crown rot.
Pairs beautifully with Russian Sage, Yarrow, Lavender, Rudbeckia, and Ornamental Grasses in pollinator gardens, xeriscapes, and long-lasting border displays.