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Plant care

Cucumber Tree Magnolia (Cucumber Tree) care

Magnolia acuminata

Also called Cucumber Tree, Cucumber Magnolia, Cucumbertree.

RHS H6USDA 3-8Pet-safeIndoor 15–24 m tall (50–80 ft) with an equal or near-equal spread

Watering rhythm

2-3weeks

Every 2–3 weeks when established; more frequently during active growth in summer

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Light

Bright indirect light (just back from a sunny window)

Soil

Moist, rich, well-drained loam; tolerates a wide pH range

Humidity

40–65%

Temp

-34 to 30°C

Pet safety

Pet-safe

Mature size

15–24 m tall (50–80 ft) with an equal or near-equal spread

Care at a glance

Light

Cucumber Tree Magnolia is what florists mean by "bright spot, no direct sun" — close enough to a south or east window to feel the brightness, with a sheer curtain or a few feet of distance keeping the sun off the leaves. Grows best in full sun to light partial shade. Tolerates dappled canopy light when young but produces the best form and most flowers in open, sunny positions with good air circulation. A phone lux-meter at the leaf surface should read 1,500-3,000 lux at noon.

Watering

Water cucumber tree magnolia every 2–3 weeks when established; more frequently during active growth in summer. 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. Requires consistently moist, deep soil. Sensitive to drought — water stress increases susceptibility to pests such as magnolia borer. Apply mulch to conserve moisture and keep roots cool.

Soil and pot

Cucumber Tree Magnolia grows best in moist, rich, well-drained loam; tolerates a wide ph range. Prefers fertile, organically amended loam with pH 5.5–7.0. Tolerates clay or sandy loam with good drainage but dislikes compacted, flooded, or salty soil. Sensitive to urban pollution. 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

Cucumber Tree Magnolia sits happiest at around 40–65% humidity and -34 to 30°C (-30 to 86°F). Tolerates normal ambient humidity. Performs best in temperate climates with cool summers; avoid hot, dry exposures. 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 cucumber tree magnolia sparingly. Apply a balanced slow-release granular fertiliser in early spring. In rich garden soils, fertilising is rarely necessary once established. Avoid excessive nitrogen, which can promote rank growth susceptible to pests. 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 cucumber tree magnolia in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Magnolia borer — Larvae of Euzophera magnolialis bore into trunks, especially on stressed trees. Maintain plant vigour with adequate moisture; avoid mechanical trunk wounds that invite egg-laying.
  • Heat and drought stress — Unlike most magnolias, Cucumber Tree is intolerant of hot, dry conditions. Leaf scorch and dieback occur in USDA zones 8–9 during hot summers. Site in cool, northern exposures in warmer regions.
  • Verticillium wilt — Soil-borne fungus causes sudden wilting and branch dieback. No chemical cure; remove and destroy infected branches, improve drainage, and avoid root injury.

Propagation

Grow from fresh seed collected in autumn when red fruits split open; cold-stratify for 3–6 months before spring sowing. Semi-hardwood cuttings in summer with rooting hormone and bottom heat are possible but difficult. Named cultivars are grafted onto seedling rootstocks. 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

Cucumber Tree Magnolia is pet-safe. ASPCA lists Magnolia as non-toxic to dogs, cats, and horses. Eating large amounts of any plant material may cause mild gastrointestinal upset in sensitive animals. 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.

Cucumber Tree Magnolia care — frequently asked questions

What is the common name for Magnolia acuminata?

Magnolia acuminata is most commonly called Cucumber Tree Magnolia, but it is also known as Cucumber Tree, Cucumber Magnolia, Cucumbertree. The names refer to the same species, so care instructions for Cucumber Tree Magnolia apply identically to anything sold as Cucumber Tree.

How much light does cucumber tree magnolia need?

Cucumber Tree Magnolia grows best in bright indirect light (just back from a sunny window). Grows best in full sun to light partial shade. Tolerates dappled canopy light when young but produces the best form and most flowers in open, sunny positions with good air circulation.

How often should I water cucumber tree magnolia?

Water cucumber tree magnolia every 2–3 weeks when established; more frequently during active growth in summer. Requires consistently moist, deep soil. Sensitive to drought — water stress increases susceptibility to pests such as magnolia borer. Apply mulch to conserve moisture and keep roots cool. 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 cucumber tree magnolia toxic to cats and dogs?

Cucumber Tree Magnolia is pet-safe. ASPCA lists Magnolia as non-toxic to dogs, cats, and horses. Eating large amounts of any plant material may cause mild gastrointestinal upset in sensitive animals.

What USDA hardiness zone does cucumber tree magnolia grow in?

Cucumber Tree Magnolia is rated for USDA zone 3-8 and RHS hardiness H6. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Cucumber Tree Magnolia deep-dive guides

Every aspect of cucumber tree magnolia care, each with its own calibrated guide:

Featured in these plant shortlists

Cucumber Tree Magnolia qualifies for 11 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Cucumber Tree Magnolia is also known as Cucumber Tree, Cucumber Magnolia, and Cucumbertree.