Symphyotrichum pilosum
hairy white oldfield aster
Overview
Symphyotrichum pilosum is a clump-forming herbaceous perennial in the family Asteraceae, growing 1-5 feet (30-150 cm) tall and 1-2 feet (30-60 cm) wide on stiff, much-branched stems covered in spreading white hairs. The narrow, lance-shaped leaves are 1-4 inches (2.5-10 cm) long, hairy on both sides, and become smaller toward the flowering tips. From late summer into autumn the plant carries hundreds of small daisy-like heads about 0.5-0.75 inch (1.2-2 cm) across, each with 16-35 white ray florets surrounding a centre of yellow disc florets that age to reddish-brown. The seed is a small, hairy achene tipped with a tuft of bristles that carries it on the wind. Symphyotrichum pilosum colonises old fields, roadsides, and disturbed ground, spreading by short rhizomes and abundant seed. It supplies late-season nectar and pollen for bees and migrating butterflies. Limitations include a tendency to self-seed widely and an open, weedy look once flowering ends, and lower stems often drop their leaves in dry summers.
Native Range
Symphyotrichum pilosum is native to central and eastern North America, ranging from Ontario and the Great Lakes south to Texas and Florida and east to the Atlantic coast. It grows in open, sunny habitats such as old fields, prairies, woodland edges, and roadsides on dry to moderately moist soils.Suggested Uses
Symphyotrichum pilosum is used in meadow and prairie plantings, pollinator and native gardens, and naturalised borders, spaced 18-24 inches (45-60 cm) apart. Its late flowers and wind-borne seed suit wildlife and restoration plantings on dry, open sites.How to Identify
Appearance
Size & Dimensions
Height1' - 5'
Width/Spread1' - 2'
Reaches mature size in approximately 2 years
Bloom Information
Symphyotrichum pilosum blooms from late summer through autumn, roughly August to October, often continuing until the first hard frost, which gives rise to the name frost aster. Each plant opens hundreds of heads over six to ten weeks. The long bloom season makes it a source of nectar after most summer flowers have faded.
Detailed Descriptions
Flower Description
White with yellow centreFoliage Description
Medium greenGrowing Conditions
Sun Requirements
Requires 6-12 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
Care & Maintenance
Care Guide
Symphyotrichum pilosum grows in full sun to light shade on average, well-drained soil and tolerates poor, dry, and rocky ground once established. Rich soil and shade produce tall, floppy stems that may need support or a midsummer trim. It withstands drought but holds its lower leaves better with occasional summer water. Plants are short-lived but renew themselves freely from self-sown seedlings. Powdery mildew can affect the foliage in humid sites with poor air movement. No fertiliser is needed, and lean conditions keep growth denser.Pruning
Symphyotrichum pilosum can be cut back by one-third in late spring or early summer to produce shorter, bushier plants with more flowering stems. Spent stems are cut to the ground in late autumn or left standing through winter for seed-eating birds. Shearing seed heads before they ripen limits self-sowing.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
late spring