Growli
Let's go

Plant care

Canna 'Yellow King Humbert' (Yellow King Humbert Canna) care

Canna 'Yellow King Humbert'

Also called Yellow King Humbert Canna.

RHS H3USDA 7-11Mildly toxic to petsIndoor 120-150 cm tall

Watering rhythm

2-3days

Water every 2-3 days to maintain consistently moist soil during the growing season

Jump to schedule→Get smart reminders in the app

Light

Direct sun (at least 4-6 hours)

Soil

Fertile, well-drained, humus-rich loam

Humidity

40-65%

Temp

15-30°C

Pet safety

Mildly toxic to pets

Mature size

120-150 cm tall

Care at a glance

Light

Canna 'Yellow King Humbert' needs sun on the leaves, not just bright ambient room light. Needs full sun for best flowering and stem strength. A minimum of 6 hours of direct sunlight per day is recommended; shadier positions produce fewer and paler flowers. 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 canna 'yellow king humbert' water every 2-3 days to maintain consistently moist soil during the growing season. 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. Apply water at the base of the plant rather than overhead to reduce disease risk. In very hot weather, large cannas can need watering daily. Ease off once the foliage starts to die down in autumn.

Soil and pot

Canna 'Yellow King Humbert' grows best in fertile, well-drained, humus-rich loam. Work in generous amounts of compost or well-rotted manure before planting. Good drainage prevents the rhizome rot that is the most common cause of failure, especially over winter. 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

Canna 'Yellow King Humbert' sits happiest at around 40-65% humidity and 15-30°C (59-86°F). Tolerates typical outdoor humidity. Mulching reduces moisture loss and helps maintain an even root environment during summer heat. If you keep the room above 15 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 canna 'yellow king humbert' sparingly. Apply a balanced slow-release granular fertiliser at planting and supplement with a liquid high-potassium feed every 2-3 weeks through the summer months to sustain continuous flowering. 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 canna 'yellow king humbert' in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Canna leaf roller — Very common; caterpillars roll leaves and feed inside. Check growing tips weekly; remove manually or apply a Bt spray.
  • Rust (Puccinia thaliae) — Orange, powdery pustules on leaf undersides during humid summers. Remove affected leaves and avoid wetting foliage.
  • Slugs and snails — Damage young emerging shoots in spring. Use iron phosphate bait or copper tape around containers.
  • Botrytis on stored rhizomes — Mould develops if rhizomes are stored too cold and damp. Allow to dry thoroughly before placing in ventilated storage.
  • Virus mosaic — Irregular light-and-dark green mottling; aphid-transmitted. Control aphids; remove and destroy infected plants.

Companion plants

Canna 'Yellow King Humbert' pairs well with Canna 'Cleopatra', Rudbeckia, Helenium, and Tithonia rotundifolia. 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 rhizomes in spring just before the growing season, with each piece having at least one eye. Pre-chit in a warm, light place before planting out after the last frost. Can be raised from seed but cultivar traits are not reliably reproduced. 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

Canna 'Yellow King Humbert' is mildly toxic to pets. Not individually listed by the ASPCA. As with other Canna cultivars, this plant is considered to have low toxicity, but ingestion may cause mild gastrointestinal irritation in dogs and cats. 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.

Canna 'Yellow King Humbert' care — frequently asked questions

What is the common name for Canna 'Yellow King Humbert'?

Canna 'Yellow King Humbert' is most commonly called Canna 'Yellow King Humbert', but it is also known as Yellow King Humbert Canna. The names refer to the same species, so care instructions for Canna 'Yellow King Humbert' apply identically to anything sold as Yellow King Humbert Canna.

How much light does canna 'yellow king humbert' need?

Canna 'Yellow King Humbert' grows best in direct sun (at least 4-6 hours). Needs full sun for best flowering and stem strength. A minimum of 6 hours of direct sunlight per day is recommended; shadier positions produce fewer and paler flowers.

How often should I water canna 'yellow king humbert'?

Water canna 'yellow king humbert' water every 2-3 days to maintain consistently moist soil during the growing season. Apply water at the base of the plant rather than overhead to reduce disease risk. In very hot weather, large cannas can need watering daily. Ease off once the foliage starts to die down in autumn. 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 canna 'yellow king humbert' toxic to cats and dogs?

Canna 'Yellow King Humbert' is mildly toxic to pets. Not individually listed by the ASPCA. As with other Canna cultivars, this plant is considered to have low toxicity, but ingestion may cause mild gastrointestinal irritation in dogs and cats.

What USDA hardiness zone does canna 'yellow king humbert' grow in?

Canna 'Yellow King Humbert' is rated for USDA zone 7-11 (lift and store in zones 6 and colder; deep mulch may protect in zone 7) and RHS hardiness H3. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Canna 'Yellow King Humbert' deep-dive guides

Every aspect of canna 'yellow king humbert' care, each with its own calibrated guide:

Featured in these plant shortlists

Canna 'Yellow King Humbert' 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

Canna 'Yellow King Humbert' is also commonly called Yellow King Humbert Canna.