Lobster Flower (Blue Coleus) care

Light

In the wild lobster flower grows on the bright edge of a forest canopy, not in the canopy and not in the open. Indoors, that translates to within a metre of an unobstructed window, sheer curtain optional. Grows well in full sun to partial shade; plants in full sun are more compact and flower more freely, while those in deeper shade tend to produce lusher foliage with slightly fewer blooms. The fastest test: a hand held at the leaf casts a soft-edged shadow at noon — sharp shadow means too much sun, no shadow means too little light.

Watering

Aim for every 2–3 weeks in summer; monthly or less in winter for lobster flower, but treat that as a starting point rather than a rule. A south-facing summer windowsill will dry the pot twice as fast as a north-facing winter room. Lift the pot; if it feels noticeably lighter than it did wet, water it. Allow the soil to dry out completely between waterings; the succulent stems store moisture effectively and will rot if kept consistently wet, especially in cool weather.

Soil and pot

Lobster Flower grows best in sandy, very well-draining succulent or cactus mix. Mix standard potting compost 50:50 with coarse sand, perlite, or pumice to achieve the sharp drainage this species demands; avoid peat-heavy or water-retentive mixes. 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

Lobster Flower sits happiest at around Low to moderate (30–50%) humidity and 7–30°C (45–86°F). Tolerates dry indoor air comfortably and does not require misting; good airflow around the plant reduces risk of fungal disease. If you keep the room above 7–30°C 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 lobster flower sparingly. Apply a balanced liquid fertiliser at half-strength once monthly during spring and summer; excessive nitrogen encourages lush, floppy growth at the expense of flowers. 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 lobster flower in the Growli community. Each is annotated with the most common cause so you know where to start.

• Root and stem rot from overwatering — Soft, blackened stem bases and wilting despite moist soil indicate rot; cut away affected tissue, allow remaining roots to dry for 24 hours, and repot in fresh dry gritty mix.
• Spider mites in hot, dry conditions — Fine webbing on the undersides of leaves and stippled, bronze foliage signal a mite infestation; increase airflow, mist undersides of leaves, and apply neem oil or insecticidal soap spray.

Propagation

Exceptionally easy — snap or cut a healthy stem section, allow the cut end to callous for a day, and push directly into barely moist, gritty soil; roots form within one to two weeks with no hormone treatment needed. 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

Lobster Flower is pet-safe. Listed as pet-safe by specialist succulent nurseries including Mountain Crest Gardens; Plectranthus species in general are classified non-toxic to cats, dogs, and horses by ASPCA (confirmed for P. australis, P. coleoides, P. oetendahlii). If ingestion of a large amount causes concern, contact your vet. 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.

Lobster Flower deep-dive guides

Every aspect of lobster flower care, each with its own calibrated guide:

• Common lobster flower problems & fixes
• Lobster Flower watering schedule
• Lobster Flower light requirements
• Best soil mix for lobster flower
• Lobster Flower fertilizing guide
• When to repot lobster flower
• How to propagate lobster flower
• How to prune lobster flower
• What's eating my lobster flower?
• Lobster Flower growth rate & size
• Lobster Flower cold hardiness
• Lobster Flower temperature & humidity
• Is lobster flower toxic to cats & dogs?
• Is lobster flower toxic to cats?
• Is lobster flower toxic to dogs?
• All 21 Plectranthus varieties
• Getting lobster flower to bloom

Featured in these plant shortlists

Lobster Flower qualifies for 10 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best pet-safe houseplants — Houseplants the ASPCA lists as non-toxic to cats and dogs — every one verified against the ASPCA toxic and non-toxic plant list.
• Best plants for a north-facing window — Houseplants for a north-facing window: bright, even, indirect light and no scorching direct sun. Each pick verified against its documented light needs.
• 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 pet-safe low-maintenance plants — Non-toxic to cats and dogs and forgiving of forgotten watering — the easiest safe choices for a busy pet household.
• Best pet-safe flowering plants — Flowering houseplants the ASPCA lists as non-toxic to cats and dogs — colour and blooms in a pet home, without the worry.
• Best pet-safe plants for bright light — Non-toxic to cats and dogs and happy in a bright, sunny spot — safe plants for your best-lit windowsill.
• Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
• Best cat-safe plants — Houseplants the ASPCA lists as non-toxic to cats (and dogs) — safe greenery for a home with a curious cat.
• Best dog-safe plants — Houseplants the ASPCA lists as non-toxic to dogs (and cats) — safe greenery for a home with a curious dog.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Lobster Flower is also known as Lobster Flower, Blue Coleus, and Spur Flower.

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