Pelargonium x domesticum 'Lavender Grand Slam' (Lavender Grand Slam pelargonium) care

Light

In the wild pelargonium x domesticum 'lavender grand slam' 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. Bright light with gentle morning sun maximises the lavender colouring and bloom count; shade from intense midday summer sun, which fades flowers and scorches foliage. 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 when the top 2-3 cm of soil is dry, roughly every 5-7 days in growth for pelargonium x domesticum 'lavender grand slam', 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. Water thoroughly, let the surface dry, then water again; reduce after the main flush and keep nearly dry in winter. Water at the base to protect the dense flower heads.

Soil and pot

Pelargonium x domesticum 'Lavender Grand Slam' grows best in free-draining loam-based potting mix. John Innes No. 2 plus grit gives drainage and stability. Avoid water-retentive composts that bring on black-leg. Neutral to slightly alkaline pH is preferred. 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

Pelargonium x domesticum 'Lavender Grand Slam' sits happiest at around 30-50% humidity and 10-21°C (50-70°F). Average to dry air suits it; the main need is ventilation, as humid, stagnant conditions encourage grey mould and rust on the foliage. If you keep the room above 10 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 pelargonium x domesticum 'lavender grand slam' sparingly. Feed every 1-2 weeks with a balanced liquid feed in spring, switching to high-potash as buds form; stop feeding after flowering and over winter. 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 pelargonium x domesticum 'lavender grand slam' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Reduced flowering without a rest — Even free-blooming regals flower best after a cool winter rest and bright spring light; warm winters cut the display.
• Pelargonium rust — Brown pustules under leaves in humid air; remove infected leaves promptly and improve airflow.
• Botrytis on dense trusses — Grey mould settles on the packed flower heads in damp air; deadhead spent blooms and ventilate well.
• Aphids and whitefly — Sap-suckers that distort new growth under glass; rinse off or treat with insecticidal soap.

Propagation

Take 8-10 cm semi-ripe cuttings from non-flowering shoots in late summer. Strip the lower leaves, allow the cut to callus, and root in gritty, just-moist compost at around 18°C; rooting takes 3-4 weeks. 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

Pelargonium x domesticum 'Lavender Grand Slam' is toxic to pets. The ASPCA lists Pelargonium species (geranium) as toxic to cats, dogs and horses. Toxic principles are geraniol and linalool, with ingestion causing vomiting, anorexia, depression and dermatitis. Keep away from pets that chew houseplants. 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.

Pelargonium x domesticum 'Lavender Grand Slam' deep-dive guides

Every aspect of pelargonium x domesticum 'lavender grand slam' care, each with its own calibrated guide:

• Pelargonium x domesticum 'Lavender Grand Slam' watering schedule
• Pelargonium x domesticum 'Lavender Grand Slam' light requirements
• Best soil mix for pelargonium x domesticum 'lavender grand slam'
• Pelargonium x domesticum 'Lavender Grand Slam' fertilizing guide
• When to repot pelargonium x domesticum 'lavender grand slam'
• How to propagate pelargonium x domesticum 'lavender grand slam'
• Pelargonium x domesticum 'Lavender Grand Slam' growth rate & size
• Pelargonium x domesticum 'Lavender Grand Slam' cold hardiness
• Pelargonium x domesticum 'Lavender Grand Slam' temperature & humidity
• Is pelargonium x domesticum 'lavender grand slam' toxic to cats & dogs?
• Is pelargonium x domesticum 'lavender grand slam' toxic to cats?
• Is pelargonium x domesticum 'lavender grand slam' toxic to dogs?
• Getting pelargonium x domesticum 'lavender grand slam' to bloom

Featured in these plant shortlists

Pelargonium x domesticum 'Lavender Grand Slam' qualifies for 4 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• 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 flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
• Houseplants toxic to cats & dogs — The common houseplants the ASPCA lists as toxic to cats and dogs — the ones to keep out of reach, each with its symptoms and a safe alternative.
• 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.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Pelargonium x domesticum 'Lavender Grand Slam' is also commonly called Lavender Grand Slam pelargonium or Regal pelargonium Lavender Grand Slam.

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