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Plant care

Aster 'Alma Potschke' (Alma Potschke aster) care

Symphyotrichum novae-angliae 'Andenken an Alma Pötschke'

Also called Alma Potschke aster, New England aster, Michaelmas daisy.

RHS H7USDA 4-8Mildly toxic to petsIndoor 90-130 cm tall

Watering rhythm

7-10days

When the top 3-5 cm of soil is dry, roughly every 7-10 days

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Light

Direct sun (at least 4-6 hours)

Soil

Average to moderately fertile, well-drained soil

Humidity

40-65%

Temp

-20 to 30°C

Pet safety

Mildly toxic to pets

Mature size

90-130 cm tall

Care at a glance

Light

Most houseplants will scorch where aster 'alma potschke' thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Full sun (6+ hours) gives the best flowering and most compact growth. In partial shade the plant tends to become taller and more prone to powdery mildew, which is its primary disease problem. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

Aim for when the top 3-5 cm of soil is dry, roughly every 7-10 days for aster 'alma potschke', but treat that as a starting point rather than a rule. A south-facing summer windowsill will dry the pot twice as fast as a north-facing winter room. Lift the pot; if it feels noticeably lighter than it did wet, water it. Established plants are reasonably drought tolerant once their root system is mature. Water consistently in the first season and during prolonged dry spells to prevent premature leaf browning at the base of the plant.

Soil and pot

Aster 'Alma Potschke' grows best in average to moderately fertile, well-drained soil. Too-rich soil encourages lush, floppy growth. A lean to average loam or clay-loam gives the best balance of height and flower production. Tolerates a range of pH from slightly acid to slightly alkaline. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Aster 'Alma Potschke' sits happiest at around 40-65% humidity and -20 to 30°C (-4 to 86°F). Adequate air circulation is the main humidity concern; powdery mildew is very common on New England asters in hot, dry conditions or where airflow is restricted. Do not plant against solid fences or walls. If you keep the room above year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed aster 'alma potschke' sparingly. Minimal feeding required on average soils. A light top-dressing of balanced granular fertiliser in early spring is sufficient; avoid high-nitrogen feeds that promote soft, mildew-prone growth at the expense of flowers. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on aster 'alma potschke' in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Powdery mildew — Almost universal on New England asters in warm dry spells; choose open, sunny sites and consider mildew-resistant selections or preventative sulphur sprays.
  • Leaf spot (Septoria) — Brown spots with darker borders on lower leaves; remove affected foliage and improve airflow.
  • Aphids — Mainly on young shoot tips in spring; treat with insecticidal soap or a strong water jet.
  • Flopping stems — Tall cultivar prone to lodging; Chelsea chop (cut back by half in late May/early June) reduces final height and eliminates the need for staking.
  • Crown congestion — Woody unproductive centres develop after 2-3 years; divide every 2-3 years in spring, discarding the old centre.

Companion plants

Aster 'Alma Potschke' pairs well with Rudbeckia fulgida, Helenium autumnale, Pennisetum alopecuroides, and Chrysanthemum 'Ruby Mound'. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Divide clumps in spring every 2-3 years, replanting vigorous outer sections 40-50 cm apart. Basal cuttings taken in spring root readily in a free-draining compost; this is also the main method for maintaining a named cultivar true to type. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Aster 'Alma Potschke' is mildly toxic to pets. Symphyotrichum novae-angliae is not individually listed by the ASPCA as toxic, but the genus and the Asteraceae family are not confirmed non-toxic either. As a precaution, treat as mildly toxic to pets and prevent ingestion, particularly by cats and dogs. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Aster 'Alma Potschke' care — frequently asked questions

What is the common name for Symphyotrichum novae-angliae 'Andenken an Alma Pötschke'?

Symphyotrichum novae-angliae 'Andenken an Alma Pötschke' is most commonly called Aster 'Alma Potschke', but it is also known as Alma Potschke aster, New England aster, Michaelmas daisy. The names refer to the same species, so care instructions for Aster 'Alma Potschke' apply identically to anything sold as Alma Potschke aster.

How much light does aster 'alma potschke' need?

Aster 'Alma Potschke' grows best in direct sun (at least 4-6 hours). Full sun (6+ hours) gives the best flowering and most compact growth. In partial shade the plant tends to become taller and more prone to powdery mildew, which is its primary disease problem.

How often should I water aster 'alma potschke'?

Water aster 'alma potschke' when the top 3-5 cm of soil is dry, roughly every 7-10 days. Established plants are reasonably drought tolerant once their root system is mature. Water consistently in the first season and during prolonged dry spells to prevent premature leaf browning at the base of the plant. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is aster 'alma potschke' toxic to cats and dogs?

Aster 'Alma Potschke' is mildly toxic to pets. Symphyotrichum novae-angliae is not individually listed by the ASPCA as toxic, but the genus and the Asteraceae family are not confirmed non-toxic either. As a precaution, treat as mildly toxic to pets and prevent ingestion, particularly by cats and dogs.

What USDA hardiness zone does aster 'alma potschke' grow in?

Aster 'Alma Potschke' is rated for USDA zone 4-8 and RHS hardiness H7. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Aster 'Alma Potschke' deep-dive guides

Every aspect of aster 'alma potschke' care, each with its own calibrated guide:

Featured in these plant shortlists

Aster 'Alma Potschke' qualifies for 4 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Aster 'Alma Potschke' is also known as Alma Potschke aster, New England aster, and Michaelmas daisy.