Growli
Let's go

Plant care

Janke's Gesneriad (Olympus Gesneriad) care

Jancaea heldreichii

Also called Janke's Gesneriad, Olympus Gesneriad, Jankaea.

RHS H5USDA 6-8Mildly toxic to petsIndoor 5–8 cm tall in flower

Watering rhythm

10-14days

Water at the root zone only when the soil approaches dryness, roughly every 10–14 days in the growing season

Jump to schedule→Get smart reminders in the app

Light

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

Soil

Very sharply drained, gritty limestone-based alpine mix

Humidity

40–60%

Temp

-10–18°C

Pet safety

Mildly toxic to pets

Mature size

5–8 cm tall in flower

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). Provide bright but indirect light, as befits its shaded cliff habitat; an alpine house with dappled glass cover, or a north-facing aspect under a rock overhang, is ideal. 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 janke's gesneriad: water at the root zone only when the soil approaches dryness, roughly every 10–14 days in the growing season. 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. Water must never contact the rosette; bottom-watering by briefly setting the pot in a shallow tray is strongly preferred; reduce to very occasional winter moisture.

Soil and pot

Janke's Gesneriad grows best in very sharply drained, gritty limestone-based alpine mix. Use a mix of equal parts coarse horticultural grit, crushed limestone, and peat-free humus; plant into a clay pot or a tufa crevice to facilitate moisture regulation and evaporation. 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

Janke's Gesneriad sits happiest at around 40–60% humidity and -10–18°C (14–64°F). Moderate ambient humidity is fine; prioritise airflow over elevated humidity to prevent fungal disease on the dense silver leaf hairs. 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 janke's gesneriad sparingly. Apply a highly diluted (quarter-strength) balanced fertiliser once in early spring only; excess nutrients produce soft, disease-prone growth incompatible with this plant's constitution. 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 janke's gesneriad in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Botrytis (grey mould) on the rosette — The densely hairy leaves trap moisture, creating ideal conditions for Botrytis cinerea in poor ventilation; grow in an alpine house with good airflow and remove any dead or dying leaves promptly.
  • Vine weevil larval root damage — Vine weevil grubs feed unseen on the roots of container-grown alpine plants; apply a horticultural grit top-dressing to deter egg-laying and consider nematode biological control in late summer.

Propagation

Leaf cuttings in late spring: detach a healthy leaf with its short petiole and insert it into a barely moist gritty mix in a propagator with shade and cool temperatures (12–15°C); germination from fresh seed is also possible but slow. 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

Janke's Gesneriad is mildly toxic to pets. Jancaea heldreichii has not been assessed by the ASPCA. No toxic principles are documented in veterinary or horticultural literature, but given the absence of a formal safety listing, a precautionary mildly-toxic rating is applied. Seek veterinary advice if a pet consumes any part of this plant. 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.

Janke's Gesneriad care — frequently asked questions

What is the common name for Jancaea heldreichii?

Jancaea heldreichii is most commonly called Janke's Gesneriad, but it is also known as Janke's Gesneriad, Olympus Gesneriad, Jankaea. The names refer to the same species, so care instructions for Janke's Gesneriad apply identically to anything sold as Olympus Gesneriad.

How much light does janke's gesneriad need?

Janke's Gesneriad grows best in medium indirect light (a couple of metres from a window). Provide bright but indirect light, as befits its shaded cliff habitat; an alpine house with dappled glass cover, or a north-facing aspect under a rock overhang, is ideal.

How often should I water janke's gesneriad?

Water janke's gesneriad water at the root zone only when the soil approaches dryness, roughly every 10–14 days in the growing season. Water must never contact the rosette; bottom-watering by briefly setting the pot in a shallow tray is strongly preferred; reduce to very occasional winter moisture. 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 janke's gesneriad toxic to cats and dogs?

Janke's Gesneriad is mildly toxic to pets. Jancaea heldreichii has not been assessed by the ASPCA. No toxic principles are documented in veterinary or horticultural literature, but given the absence of a formal safety listing, a precautionary mildly-toxic rating is applied. Seek veterinary advice if a pet consumes any part of this plant.

What USDA hardiness zone does janke's gesneriad grow in?

Janke's Gesneriad is rated for USDA zone 6-8 and RHS hardiness H5. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Janke's Gesneriad deep-dive guides

Every aspect of janke's gesneriad care, each with its own calibrated guide:

Featured in these plant shortlists

Janke's Gesneriad qualifies for 7 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Janke's Gesneriad is also known as Janke's Gesneriad, Olympus Gesneriad, and Jankaea.