Grosso Lavender (Lavandin) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Full sun, at least 6-8 hours of direct light. Anything less reduces the dense flowering and oil content this lavandin is grown for. If your only bright window faces south, that's perfect for grosso lavender — same window any aroid would fry on.

Watering

Watering grosso lavender: when the top 5 cm of soil is dry, about every 10-14 days once established. 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. Water deeply then allow to dry out. Excess moisture, especially in winter, causes root rot far more often than drought does.

Soil and pot

Grosso Lavender grows best in free-draining gritty, neutral-to-alkaline loam. Lean soil with excellent drainage; add grit, sand, or gravel. Tolerates chalk well. Avoid moisture-retentive composts and heavy clay without amendment. 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

Grosso Lavender sits happiest at around 30-50% humidity and 10-30°C (50-86°F). Likes dry air and open airflow. Damp, still conditions encourage fungal problems; generous spacing keeps the large mounds healthy. 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 grosso lavender sparingly. Minimal feeding. One light low-nitrogen application in spring is sufficient. Rich feeding produces soft growth, fewer flowers, and weaker scent. 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 grosso lavender in the Growli community. Each is annotated with the most common cause so you know where to start.

• Root rot and winter wet — Heavy or soggy soil rots the crown. Plant on a slope or raised gritty bed and avoid irrigation in cold, damp months.
• Bare, woody centre with age — Like all lavandins it splits and goes bald if unpruned. Prune annually after flowering, staying in green growth, never cutting into old bare wood.
• Flopping after rain or feeding — Long, heavy flower stalks bend under wet weather or rich soil. Keep it lean and unfed and shear flower stems promptly.
• Reduced bloom in shade or crowding — Shade and poor airflow cut flowering and invite mildew. Site in open full sun with space around each plant.

Propagation

'Grosso' is sterile and produces no viable seed, so it is propagated exclusively by cuttings. Take semi-ripe cuttings in summer and root in a gritty, free-draining medium. 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

Grosso Lavender is toxic to pets. The ASPCA lists Lavender (Lavandula) as toxic to cats, dogs, and horses; this applies to the Lavandula × intermedia hybrids. Toxic principles are linalool and linalyl acetate, causing nausea, vomiting, and loss of appetite. Keep plants and lavender oils away from pets. 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.

Grosso Lavender deep-dive guides

Every aspect of grosso lavender care, each with its own calibrated guide:

• Grosso Lavender watering schedule
• Grosso Lavender light requirements
• Best soil mix for grosso lavender
• Grosso Lavender fertilizing guide
• When to repot grosso lavender
• How to propagate grosso lavender
• Grosso Lavender growth rate & size
• Grosso Lavender cold hardiness
• Grosso Lavender temperature & humidity
• Is grosso lavender toxic to cats & dogs?
• Is grosso lavender toxic to cats?
• Is grosso lavender toxic to dogs?

Featured in these plant shortlists

Grosso Lavender qualifies for 1 curated Growli shortlist — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best fragrant houseplants — Indoor plants with scented flowers or aromatic foliage — greenery you can smell, selected from our care library.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

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Grosso Lavender is also commonly called Lavandin.

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