Leucanthemum × superbum 'Alaska' (Alaska Shasta daisy) care

Light

Leucanthemum × superbum 'Alaska' needs sun on the leaves, not just bright ambient room light. Full sun, at least 6 hours a day, gives the heaviest flowering and sturdiest stems. It accepts light afternoon shade in hot climates but blooms less and grows leggier in true shade. A south or west-facing windowsill in the northern hemisphere is the default; anywhere else, expect the plant to stretch and pale out within a season.

Watering

Water leucanthemum × superbum 'alaska' when the top 2-3 cm of soil is dry, roughly weekly; more in extended heat. The actual day count varies with pot size, light, and season — the finger test (or lifting the pot to feel its weight) is more reliable than a fixed calendar. Empty any drainage saucer afterwards so the pot isn't sitting in water. Water consistently to establish, then in dry spells; mature plants tolerate short droughts. Steady moisture with good drainage gives the longest flowering and healthiest foliage.

Soil and pot

Leucanthemum × superbum 'Alaska' grows best in average, well-drained garden soil. Undemanding and adaptable, growing in most soils with good drainage. It dislikes winter wet, which rots the crown; neutral pH and moderate fertility produce the sturdiest plants. 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

Leucanthemum × superbum 'Alaska' sits happiest at around Ambient outdoor humidity humidity and -34-30°C (-30-86°F). A hardy border perennial indifferent to air humidity. Good spacing and air movement reduce the risk of leaf spot and powdery mildew during muggy weather. 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 leucanthemum × superbum 'alaska' sparingly. A single spring application of balanced general fertiliser as growth begins is sufficient; overfeeding produces soft, floppy growth. Deadheading spent flowers extends the season more effectively than extra feeding. 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 leucanthemum × superbum 'alaska' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Crown rot in winter wet — Heavy, waterlogged soil rots the crown in cold months. Plant in well-drained ground, keep mulch off the crown, and divide congested clumps regularly.
• Powdery mildew and leaf spot — Damp, crowded growth invites fungal foliage disease. Space plants for airflow, water at the base rather than overhead, and remove affected leaves.
• Clump centre dying out — Older clumps decline and hollow in the middle. Lift and divide every 2-3 years in spring or autumn to keep flowering strong and even.
• Self-seeding and reversion — 'Alaska' sets viable seed and self-sows; seedlings vary and can crowd the parent. Deadhead to limit unwanted seedlings if a tidy clump is wanted.

Propagation

Divide clumps every 2-3 years in spring or early autumn, or take basal cuttings in spring. Uniquely among these cultivars 'Alaska' also comes reasonably true from seed sown in spring, making it easy to bulk up. 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

Leucanthemum × superbum 'Alaska' is toxic to pets. The ASPCA lists daisy (Chrysanthemum spp., Compositae) as toxic to dogs and cats, and Shasta daisy was formerly classified as Chrysanthemum × superbum within the same family. The toxic principles are sesquiterpene lactones, pyrethrins and other irritants; ingestion can cause vomiting, diarrhoea, hypersalivation, incoordination and dermatitis. 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.

Leucanthemum × superbum 'Alaska' deep-dive guides

Every aspect of leucanthemum × superbum 'alaska' care, each with its own calibrated guide:

• Leucanthemum × superbum 'Alaska' watering schedule
• Leucanthemum × superbum 'Alaska' light requirements
• Best soil mix for leucanthemum × superbum 'alaska'
• Leucanthemum × superbum 'Alaska' fertilizing guide
• When to repot leucanthemum × superbum 'alaska'
• How to propagate leucanthemum × superbum 'alaska'
• Leucanthemum × superbum 'Alaska' growth rate & size
• Leucanthemum × superbum 'Alaska' cold hardiness
• Leucanthemum × superbum 'Alaska' temperature & humidity
• Is leucanthemum × superbum 'alaska' toxic to cats & dogs?
• Is leucanthemum × superbum 'alaska' toxic to cats?
• Is leucanthemum × superbum 'alaska' toxic to dogs?
• Getting leucanthemum × superbum 'alaska' to bloom

Featured in these plant shortlists

Leucanthemum × superbum 'Alaska' qualifies for 5 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best drought-tolerant houseplants — Houseplants that prefer to dry out — forgiving of forgotten watering and ideal for travel or busy weeks.
• Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
• Houseplants toxic to cats & dogs — The common houseplants the ASPCA lists as toxic to cats and dogs — the ones to keep out of reach, each with its symptoms and a safe alternative.
• Best houseplants for full sun — Houseplants that want direct sun — the species for a hot south or west-facing windowsill where shade-lovers scorch.
• Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Leucanthemum × superbum 'Alaska' is also commonly called Alaska Shasta daisy or classic Shasta daisy.

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