Growing Asters: Late-Season Perennial Flowers for Color and Pollinators

Asters are daisy-like perennials with starry flower heads. Delightful late summer/autumn color when other blooms fade. Height: 8 inches to 8 feet by type. Fit almost any garden—borders, rock gardens, wildflower gardens. Attract butterflies!

Planting

• Prefer cool, moist summers, especially cool nights.
• Full to partial sun.
• Soil: moist, well-drained, average to humus-rich.
• Early-mid spring. Fertilize pre-plant.
• From seed: germination uneven. Indoors winter: sow in pots/flats, refrigerate 4–6 weeks, then sunny spot.
• Seeds 1 inch deep.
• Many buy potted nursery plants.
• Space 1–3 ft by type.
• Water in well. Mulch after planting for cool soil, weed prevention. Replanting shoots: use vigorous young shoots.

Care

• Spring: thin compost layer + 2-inch mulch.
• <1 inch rain/week: water regularly in summer. Moisture-sensitive—too much or little = lower foliage loss or poor flowering. Watch stressed plants; adjust watering.
• Stake tall varieties. Pinch young shoots for bushiness.
• Cut back winter after foliage dies.
• Divide every 2–3 years in spring for vigor and flower quality.

Pests and Diseases

• Susceptible: powdery mildew, rusts, white smut, leaf spots, stem cankers, aphids, tarsonemid mites, slugs, snails, nematodes. Choose resistant varieties.

Recommended Varieties

• King George (Aster amellus) – large violet-blue flowers
• Silver Spray (Aster cordifolius) – pink-tinged white flowers
• Nanus (Aster thomsonii) – star-shaped lilac-blue flowers

Wit & Wisdom

Asters, September birth flowers, were once burned to ward off serpents.