Garden Care Guide

Alpine Aster Care

Aster alpinus

It likes cool summers, full sun and very well-drained, chalky soil. It struggles in summer in hot climates like Izmir, so it is recommended to grow it in a spot with afternoon shade and good air circulation.

Hardy · -30 °C / -22 °F

Monthly care calendar

Timings are for a temperate Northern Hemisphere climate. In warmer areas tasks start earlier, in colder areas later; in the Southern Hemisphere shift them by six months.

January
  • General care: Make sure water does not collect at the base of the plant in the winter rains and that drainage is working well.
  • Pests & diseases: Root rot is the biggest risk in winter.
February
  • Pruning: If dead stems from the previous year have not been removed, cut them back before new growth begins.
  • General care: Remove weeds around the plant.
  • Pests & diseases: General check.
March
  • Watering: If the soil is dry, water lightly (2-3 L/m²).
  • Fertilizing: Apply a balanced fertilizer or well-rotted organic fertilizer once when it wakes from dormancy.
  • General care: The best time to propagate by root division every 2-3 years.
  • Pests & diseases: Check the new shoots for slugs.
April
  • Watering: If there is no rainfall, water every 15 days.
  • Plant protection: Start checking the leaves for signs of powdery mildew.
  • General care: Continue clearing weeds.
  • Pests & diseases: Aphids may be seen on new shoots.
May
  • Watering: If there is no rainfall, water once a week.
  • Pruning: Regularly remove spent flowers at the base; this encourages new flowering.
  • Plant protection: If the weather is humid, the risk of powdery mildew increases; use a protective fungicide if necessary.
  • General care: Spread a 5-7 cm layer of mulch over the root zone; it retains soil moisture and suppresses weeds. Do not pile mulch against the trunk.
  • Pests & diseases: Good air circulation is important against powdery mildew.
June
  • Watering: Water deeply twice a week; prefer infrequent and generous watering over small and frequent. Water so that the soil is wetted 10-15 cm down from the surface.
  • Pruning: Regularly remove spent flowers at the base; this encourages new flowering.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: To preserve soil moisture, cover the root zone with a thin layer of gravel or organic mulch.
  • Pests & diseases: Look for white, powdery spots on the leaves (powdery mildew). Thinning dense branches to increase airflow slows its spread.
July
  • Watering: Water deeply twice a week; prefer infrequent and generous watering over small and frequent. Water so that the soil is wetted 10-15 cm down from the surface.
  • Fertilizing: Never apply fertilizer.
  • Pruning: Regularly remove spent flowers at the base; this encourages new flowering.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Regular watering and afternoon shade are critical for keeping the plant healthy.
  • Pests & diseases: Look for white, powdery spots on the leaves (powdery mildew). Thinning dense branches to increase airflow slows its spread.
August
  • Watering: Water deeply twice a week; prefer infrequent and generous watering over small and frequent. Water so that the soil is wetted 10-15 cm down from the surface.
  • Pruning: Regularly remove spent flowers at the base; this encourages new flowering.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Focus only on the plant's survival; do not overdo care.
  • Pests & diseases: Look for white, powdery spots on the leaves (powdery mildew). Thinning dense branches to increase airflow slows its spread.
September
  • Watering: If there is no rainfall, water once a week.
  • Pruning: Regularly remove spent flowers at the base; this encourages new flowering.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: The plant comes out of summer stress and begins to recover. This is a suitable month for new planting.
  • Pests & diseases: Look for white, powdery spots on the leaves (powdery mildew). Thinning dense branches to increase airflow slows its spread.
October
  • Watering: If there is no rainfall, water every 15 days.
  • General care: The plant prepares for winter dormancy.
  • Pests & diseases: Clear fallen leaves to reduce disease risk.
November
  • Pruning: After the first frosts, or when the leaves have dried out completely, cut the plant so that it stays 5 cm above the soil.
  • General care: To protect the roots from excess winter wetness, you can add gravel around the plant.
  • Pests & diseases: General check.
December
  • General care: Make sure drainage is working.
  • Pests & diseases: Beware of the risk of root rot.

The care advice on this page is general and for information only; it is not professional advice. Plant age, soil and your garden’s microclimate can change the outcome. Plant protection products are mentioned only as general information; they are regulated, and the choice, dose and timing must be decided by a qualified professional under local rules. Consult a landscape architect or agronomist before applying.

Want reminders for every plant in your garden? Our garden-care app with monthly task lists and frost alerts is currently available in Turkish; the English version is on the way.

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