Great Design Plant: Towering Colewort — Playful Drama for Cool-Climate Gardens

Imagine baby’s breath on steroids — that’s colewort (Crambe cordifolia, aka giant crambe). Oversize foliage and 7-ft flower spires evoke tropical fun for gardeners in colder, drier regions. A single specimen anchors diverse plantings with bold physical presence.

Botanical name: Crambe cordifolia
Common names: Colewort, giant crambe
Zones: 5–8 (hardy to –20°F); dislikes hot, humid climates
Elevation: To 7,000 ft
Water: Moderate
Light: Full sun
Size: 4–7 ft tall × 4–5 ft wide
Benefits: Supersize fun; strong contrast to fine-textured plants
Season: Flowers June–July; showy foliage spring–fall
Plant: Spring to fall

Distinguishing Traits

Rhubarb-like foliage clump (leaves to 10″). Hundreds of tiny white flowers form a dense, cloud-like inflorescence on sturdy 7-ft stalks.

How to Use It

Best as a single accent specimen, not scattered. Pair with classic June bloomers: peony (Paeonia spp.), Oriental poppy (Papaver orientale), iris (Iris spp.), roses (Rosa spp.). Silvery-blue/gray companions shine: Powis Castle sage (Artemisia), blue oat grass (Helictotrichon sempervirens), rose campion (Lychnis coronaria).

Planting Notes

Full sun preferred; tolerates partial shade. Moderate water, average well-drained soil. Despite bulky roots, transplants successfully in early spring as leaves emerge.