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Oclemena acuminata

whorled wood aster

Asteraceae Northeastern North America

Attracts Pollinators Attracts Butterflies

Native to North America

SunPart Shade – Full Shade

WaterMedium

HardinessZones 3–7

Overview

Oclemena acuminata, the whorled wood aster, is a herbaceous perennial in the Asteraceae growing 8-32 inches (20-80 cm) tall and 12-24 inches (30-60 cm) wide from slender, creeping rhizomes. Thin, sharply toothed leaves taper to a long, drawn-out point and are broadest above the middle, crowding toward the top of the stem so they appear loosely whorled. In late summer and autumn the stems carry a few loose flower heads, each 1-1.5 inches (2.5-4 cm) across with 6-15 narrow white rays, sometimes tinged pink or purple, around a yellow centre that ages to reddish. The plant grows in cool, moist, acidic woodland, on shaded slopes, and along forest edges, often spreading into open colonies by rhizome. It tolerates deep shade better than most asters but flowers sparsely where shade is dense and soil is dry. The zigzag stems and few large heads give it a more open, sprawling look than the dense fall asters of open ground.

Native Range

Native to northeastern North America, from eastern Canada south through New England, New York, and the Appalachian Mountains to the southern Appalachians. It grows in cool, moist, acidic woods, on shaded mountain slopes, and along forest edges and trails.

Suggested Uses

Used in shade and woodland gardens, native plantings, and naturalised colonies under trees, spaced 12-18 inches (30-45 cm) apart. It suits cool, moist, shaded areas where many asters fail. The open habit and modest bloom make it less suited to formal borders or sunny, dry sites.

How to Identify

Recognised by thin, sharply toothed leaves that taper to a long point and cluster near the top of the stem in a loose whorl-like arrangement. The few, relatively large flower heads have narrow white rays around a yellow disc that reddens with age. The crowded upper leaves and zigzag stem separate it from Eurybia divaricata, the white wood aster, which has heart-shaped lower leaves.

Appearance

Size & Dimensions

Height8" - 2'8"

Width/Spread1' - 2'

Reaches mature size in approximately 2 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~5 weeks

Summer Fall

Flowers open from late summer into autumn, mainly August through October. Each stem bears only a few heads, opening over four to six weeks. Bloom is heavier in dappled light and sparse where shade is deep or soil is dry.

Detailed Descriptions

Flower Description

white rays with yellow disc aging reddish

Foliage Description

green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 2-6 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range4.5 - 6.0(Acidic)

357912

Soil Types

loam peat

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2-3 years

Care & Maintenance

Care Guide

Grows in partial to full shade in cool, moist, acidic soil rich in leaf litter, at a pH around 4.5-6.0. Steady soil moisture supports fuller flowering, while hot, dry sites cause leaf scorch and weak bloom. It spreads slowly by rhizome to form colonies and seldom needs feeding in humus-rich woodland soil. Propagation is by division in spring or autumn or from fresh seed. Hardy in USDA zones 3-7.

Pruning

Needs little pruning. Spent flowering stems are cut back in late autumn or left standing for winter structure and seed for birds. Old stems are removed at ground level in late winter before new growth begins.

Pruning Schedule

winter