Rudbeckia occidentalis aka Western Coneflower

Rudbeckia occidentalis, or western coneflower, belongs to the daisy family, Asteraceae. It comes from the western United States. It is not native to Britain or Ireland. This herbaceous perennial forms an upright clump with a bushy outline. Its leaves die back as the growing season ends. The plant returns as a perennial rather than completing its life in one year.

Garden plants reach about 5–8 feet [1.5–2.5 metres] tall. The RHS description gives a height of around 6.6 feet [2 metres]. Its listed garden range allows for taller plants. Clumps spread about 1.6–3.3 feet [0.5–1 metre] across. Plants take two to five years to reach full size. Green leaves range from oval to lance-shaped. They can reach about 1 foot [0.3 metres] long. Leafy stems branch as they rise above the clump.

The flowers appear from midsummer into early autumn. Each flower head has a tall, dark brown to black cone. Green bracts form a ring around its base. The heads lack the showy ray flowers found on many coneflowers. Their dark cones give the plant a distinct look in borders. The stems also suit cutting for indoor use. After bloom, gardeners can cut the spent stems back. Leaving them standing adds interest through winter.

Grow western coneflower in moderately fertile soil that stays moist. It needs good drainage as well as a steady moisture supply. Clay and loam both suit it. It accepts acid, neutral, and alkaline soil. Full sun gives the best flowering, though plants tolerate light shade. The RHS lists both exposed and sheltered sites as suitable. Its H6 rating indicates hardiness across Britain and northern Europe. That rating covers winter lows of about −20 to −15°C. Divide clumps every three to five years to keep growth strong. Sow seed or divide plants in spring to raise more.

Its height suits beds, borders, and prairie-style planting. It also fits cottage gardens, wildflower meadows, and wildlife gardens. The RHS includes city gardens and courtyards among suitable settings. Young growth can suffer damage from slugs. Aphids and leaf and bud eelworms may also attack plants. Powdery mildew can occur, with dry soil raising the risk. The supplied sources give no guidance on edible uses or toxicity. They therefore provide no basis for treating any part as food.