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Keisk's Leucothoe (Keiskei fetterbush) care

Leucothoe keiskei

Also called Keisk's leucothoe, Keiskei fetterbush, Japanese leucothoe.

RHS H5USDA 5–8Toxic to petsIndoor 30–60 cm tall × 45–60 cm wide (12–24 in × 18–24 in)

Watering rhythm

5-7days

Every 5–7 days in the growing season; sensitive to both drought and waterlogging

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Light

Medium indirect light (a couple of metres from a window)

Soil

Moist, well-drained, acidic; pH 4.5–6.5

Humidity

Moderate (45–70%)

Temp

-27°C to 25°C

Pet safety

Toxic to pets

Mature size

30–60 cm tall × 45–60 cm wide (12–24 in × 18–24 in)

Care at a glance

Light

The Goldilocks zone. Not the south-facing windowsill (too hot, too direct), not the back of the room (too dim, growth stalls). Performs best in partial shade with bright, indirect light. Tolerates deeper shade than many leucothoes but produces better autumn colour with some light exposure. Avoid direct afternoon sun, especially in hot summers, which scorches the fine-textured foliage. If you can't decide, a free phone lux-meter app aimed at the leaf at noon should read between 800 and 1,500 lux.

Watering

Watering keisk's leucothoe: every 5–7 days in the growing season; sensitive to both drought and waterlogging. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Requires moist but well-drained acidic soil; overwatering is the most common cause of failure in cultivation. Do not allow the root zone to become saturated. Water deeply and allow the top layer to begin drying before re-watering. Soft or rainwater is preferred.

Soil and pot

Keisk's Leucothoe grows best in moist, well-drained, acidic; ph 4.5–6.5. Ericaceous or sandy loam soil with high organic content is ideal. Excellent drainage is critical; grow in raised beds or containers with ericaceous compost if garden soil is heavy or neutral. Avoid waterlogged and alkaline soils. 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

Keisk's Leucothoe sits happiest at around Moderate (45–70%) humidity and -27°C to 25°C (-17°F to 77°F). Adapted to humid temperate Japanese mountain climates. Standard garden humidity in a shaded position is adequate. Avoid hot, arid conditions. Container plants should not be placed near indoor heating sources. 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 keisk's leucothoe sparingly. Grows slowly and has low fertiliser requirements. Apply a dilute ericaceous liquid or slow-release granule feed once in early spring. Over-fertilising promotes soft growth and reduces the natural red winter colour. Annual top-dressing with leaf mould is beneficial. 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 keisk's leucothoe in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Root rot from overwatering — The most frequent cultivation problem; waterlogged soil rapidly kills the root system. Use free-draining ericaceous compost, ensure containers have adequate drainage holes, and do not leave the plant sitting in water-filled saucers.
  • Poor winter colour in deep shade — The attractive red winter foliage colour only develops with some light exposure. Deep shade produces uniformly green leaves year-round. Move container plants to a brighter, frost-protected position in autumn to enhance the seasonal display.
  • Fungal leaf spot — As with all leucothoes, humid stagnant conditions promote fungal leaf spotting. Ensure good air circulation, water at the base, and remove affected leaves promptly to limit spread.

Propagation

Semi-ripe cuttings in summer in ericaceous cutting compost with bottom heat are the primary propagation method; variegated and coloured cultivars like 'Royal Ruby' must be vegetatively propagated to come true. Division of established clumps is possible in early spring. Seed is occasionally used but grows slowly. 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

Keisk's Leucothoe is toxic to pets. ASPCA lists Dog Hobble (Leucothoe species) as toxic to dogs, cats, and horses. The toxic principle is grayanotoxin. Clinical signs include vomiting, diarrhea, hypersalivation, cardiovascular collapse, weakness, low blood pressure, and potentially coma or death. L. keiskei shares this family toxicity; keep away from all pets and livestock. 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.

Keisk's Leucothoe care — frequently asked questions

What is the common name for Leucothoe keiskei?

Leucothoe keiskei is most commonly called Keisk's Leucothoe, but it is also known as Keisk's leucothoe, Keiskei fetterbush, Japanese leucothoe. The names refer to the same species, so care instructions for Keisk's Leucothoe apply identically to anything sold as Keiskei fetterbush.

How much light does keisk's leucothoe need?

Keisk's Leucothoe grows best in medium indirect light (a couple of metres from a window). Performs best in partial shade with bright, indirect light. Tolerates deeper shade than many leucothoes but produces better autumn colour with some light exposure. Avoid direct afternoon sun, especially in hot summers, which scorches the fine-textured foliage.

How often should I water keisk's leucothoe?

Water keisk's leucothoe every 5–7 days in the growing season; sensitive to both drought and waterlogging. Requires moist but well-drained acidic soil; overwatering is the most common cause of failure in cultivation. Do not allow the root zone to become saturated. Water deeply and allow the top layer to begin drying before re-watering. Soft or rainwater is preferred. 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 keisk's leucothoe toxic to cats and dogs?

Keisk's Leucothoe is toxic to pets. ASPCA lists Dog Hobble (Leucothoe species) as toxic to dogs, cats, and horses. The toxic principle is grayanotoxin. Clinical signs include vomiting, diarrhea, hypersalivation, cardiovascular collapse, weakness, low blood pressure, and potentially coma or death. L. keiskei shares this family toxicity; keep away from all pets and livestock.

What USDA hardiness zone does keisk's leucothoe grow in?

Keisk's Leucothoe is rated for USDA zone 5–8 and RHS hardiness H5. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Keisk's Leucothoe deep-dive guides

Every aspect of keisk's leucothoe care, each with its own calibrated guide:

Featured in these plant shortlists

Keisk's Leucothoe qualifies for 6 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Keisk's Leucothoe is also known as Keisk's leucothoe, Keiskei fetterbush, and Japanese leucothoe.