Six Hills Giant Catmint (tall catmint) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Full sun, 6 or more hours daily, gives the strongest stems and heaviest flowering. Partial shade makes this vigorous cultivar especially prone to flopping open. If your only bright window faces south, that's perfect for six hills giant catmint — same window any aroid would fry on.

Watering

Watering six hills giant catmint: when the top 3-4 cm of soil is dry; about every 7-10 days while establishing, then seldom. 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. Highly drought-tolerant once rooted in. Water deeply but infrequently and let the soil dry out between waterings; constant moisture rots the crown.

Soil and pot

Six Hills Giant Catmint grows best in free-draining loam or sandy soil, neutral to alkaline. Thrives on poor, gritty, chalky ground. Rich or wet soils make this big cultivar flop badly and shorten its life. Improve clay with grit before planting. 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

Six Hills Giant Catmint sits happiest at around 30-50% humidity and 15-27°C (59-81°F). Likes dry air and breezy, open sites. Outdoor humidity is fine; its size means crowding raises mildew risk, so give it generous space for airflow. 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 six hills giant catmint sparingly. A spare feeder. One spring dose of balanced fertiliser or a light compost mulch suffices. Rich feeding worsens this cultivar's tendency to grow tall and collapse. 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 six hills giant catmint in the Growli community. Each is annotated with the most common cause so you know where to start.

• Heavy flopping — Its height makes splaying almost guaranteed by midsummer. Provide twiggy supports early, or shear the whole plant by half after the first flush to rebuild a denser, self-supporting mound.
• Powdery mildew — White coating in humid, crowded plantings. Space generously, cut out affected stems, and water at the base rather than overhead.
• Crown rot in wet sites — Collapse and blackening at the base in poorly drained or winter-wet ground. Plant high in sharply drained soil to keep the crown dry.
• Cat damage — The scent draws cats that roll on and crush the clump. Cage or stake young plants until the crown is large and established.

Propagation

Divide clumps in spring or autumn, or take basal softwood cuttings in late spring. This sterile hybrid cultivar does not set viable seed and must be propagated vegetatively to stay true. 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

Six Hills Giant Catmint is mildly toxic to pets. Nepeta. The ASPCA lists catnip (Nepeta cataria), the closest listed relative, as toxic to cats; toxic principle nepetalactone, causing vomiting and diarrhoea plus sedation or excitation. This catmint carries the same aromatic oil, so treat as mildly toxic and consult a vet if a pet eats a large quantity. 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.

Six Hills Giant Catmint deep-dive guides

Every aspect of six hills giant catmint care, each with its own calibrated guide:

• Six Hills Giant Catmint watering schedule
• Six Hills Giant Catmint light requirements
• Best soil mix for six hills giant catmint
• Six Hills Giant Catmint fertilizing guide
• When to repot six hills giant catmint
• How to propagate six hills giant catmint
• Six Hills Giant Catmint growth rate & size
• Six Hills Giant Catmint cold hardiness
• Six Hills Giant Catmint temperature & humidity
• Is six hills giant catmint toxic to cats & dogs?
• Is six hills giant catmint toxic to cats?
• Is six hills giant catmint toxic to dogs?
• Getting six hills giant catmint to bloom

Featured in these plant shortlists

Six Hills Giant Catmint qualifies for 4 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.
• 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 fast-growing houseplants — Houseplants documented as fast or vigorous growers — quick to fill a pot, cover a pole or trail down a shelf.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Six Hills Giant Catmint is also commonly called Six Hills Giant catmint or tall catmint.

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