Globe Thistle

Globe thistle (Echinops ritro) is a clump-forming perennial that grows 3 to 4 feet (91 to 122 cm) tall and 2 to 2.5 feet (61 to 76 cm) wide. It has stiff, spiny, grayish-green leaves and grayish-white stems. Its round, steel-blue flowerheads, about 1 to 2 inches (2.5 to 5 cm) across, appear from mid-summer through September. The plant is native to central and southeastern Europe and central Asia.

Start seeds indoors in cell trays or seedling containers about 6 to 8 weeks before planting out, and cover them only lightly, since some light helps germination. Harden the seedlings off and move them outdoors once frost danger has passed. You can also sow directly outdoors once the soil has reached at least 65 °F (18 °C), covering the seed lightly with soil. Seeds usually sprout in 14 to 21 days when kept at 65 to 75 °F (18 to 24 °C).

The plant is best propagated from seed in spring, and it will self-seed. Division and root cuttings are also listed as propagation methods, but the taproot makes division tricky.

Full sun gives the sturdiest plants. It also tolerates partial shade, though stems may get lanky or floppy there or in rich soil, and staking is sometimes needed. Avoid wet, soggy, or rich, amended soil. Once established, it is drought-tolerant. Very light shade during the hottest part of the day may help the foliage keep its good looks.

Remove spent blooms to encourage reblooming, and deadhead before seed sets if you don’t want seedlings. It needs very well-drained soil to get through winter.

Few insect pests or diseases are significant for this plant. Watch for aphids, leaf miners, thrips, slugs, and snails. Too much water or poor air circulation can lead to root rot and powdery mildew. It may reseed and spread. It is tolerant of deer and rabbits.

For dried arrangements, cut the flowers when they are young and dry them in a warm, dry room to keep the deep blue color.

Globe thistle is listed as non-toxic to both cats and dogs.