Aster divaricatus (White Wood Aster) — Clump-forming, upright to bushy

Overview

Aster divaricatus is a clump-forming, upright to bushy perennial in the genus Aster, part of the Asteraceae family, with deciduous; simple, often narrow and roughly textured foliage. Aster divaricatus grows best in full sun, and tolerates fertile loam; avoid thin and dry soils soils and neutral to slightly alkaline pH. Its UK hardiness is rated H6–H7. Suggested uses include borders, woodland gardens and naturalizing. It is native to Eastern North America.

About

Aster divaricatus is a clump-forming perennial that produces white flowers from August to October. It carries narrow, roughly textured leaves which are shed in winter and forms upright, multi-stemmed clumps. Best grown in fertile, moist loam on south, east or west-facing sites. Very hardy to fully hardy in UK conditions (H6–H7).

About the genus

Aster is a genus of perennial flowering plants in the family Asteraceae. Its circumscription has been narrowed, and it now encompasses around 170 species, all but one of which are restricted to Eurasia; many species formerly in Aster are now in other genera of the tribe Astereae. Aster amellus is the type species of the genus and the family Asteraceae.

Wikipedia contributors, "Aster (genus)", CC BY-SA 4.0 — Aster (genus)

In the garden

Aster divaricatus originates from eastern North America and brings late-summer to autumn interest with clouds of small white flowers between August and October. The plant forms upright, multi-stemmed clumps with simple, often narrow leaves that are deciduous, so it clears away naturally before winter. Those stems produce airy flower heads that open as many shrubs finish flowering. Place it in full sun on a fertile loam that remains moist but drains freely; avoid thin, dry soils and aim for a neutral to slightly alkaline pH. It tolerates both exposed and sheltered positions and will withstand British winters classified between very hardy and fully hardy (H6–H7). Space plants to allow airflow around the clump so stems remain clean and flowers show to advantage. White Wood Aster suits borders and woodland-edge planting as well as naturalising through long grass or understorey planting where a late flush of white will extend the season. In a mixed border, it complements shrubs and perennials that have finished flowering by producing a light, late display on tall, slender stems that carry into October.

Growing conditions

Best soil and position for Aster

Sunlight: Full sun
Soil type: Fertile loam; avoid thin, dry soils
Soil pH: Neutral to slightly alkaline
Soil moisture: Moist but well drained
Aspect: South, east or west facing
Exposure: Exposed or sheltered
UK hardiness: H6–H7

Plant details

Aster divaricatus size, habit and characteristics

Plant type: Perennial
Habit: Clump-forming, upright to bushy
Foliage: Deciduous; simple, often narrow and roughly textured
Suggested uses: Borders, woodland gardens, naturalizing
Native to: Eastern North America

Care notes

Pruning and caring for Aster divaricatus

Cultivation: Plant in an open, airy position — crowding is what brings on mildew. Divide every second or third year to maintain vigour, and pinch or Chelsea-chop the taller kinds in late spring to reduce the need for staking.
Pruning: Deadhead to prolong the display, then cut stems to the base after flowering, or leave them standing through winter for structure and wildlife.
Propagation: Divide in spring, replanting only the vigorous outer growth. Basal cuttings taken in spring root readily.
Pest resistance: Slugs may take young shoots in spring; otherwise generally trouble-free.
Disease resistance: Powdery mildew is the main weakness, especially among the older novi-belgii cultivars. The frikartii hybrids and the aster relatives are markedly more resistant.

Frequently asked questions

How do I grow Aster divaricatus?

Plant in an open, airy position — crowding is what brings on mildew. Divide every second or third year to maintain vigour, and pinch or Chelsea-chop the taller kinds in late spring to reduce the need for staking.

Where is the best place to plant Aster divaricatus?

Aster divaricatus prefers full sun. It suits exposed or sheltered positions.

What soil does Aster divaricatus need?

Aster divaricatus grows best in fertile loam; avoid thin and dry soils soil. It prefers neutral to slightly alkaline soil. Aim for soil that stays moist but well drained.