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Plant care

Jagged Lavender (Fern leaf lavender) care

Lavandula pinnata

Also called Jagged lavender, Fern leaf lavender, Pinnate lavender.

RHS H2USDA 9-11Toxic to petsIndoor 60–100 cm tall and 60–90 cm wide (24–40 in × 24–36 in).

Watering rhythm

10-14days

Every 10–14 days in summer; every 3–4 weeks in winter

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Light

Direct sun (at least 4-6 hours)

Soil

Very free-draining, gritty or sandy loam, pH 6.5–8.0

Humidity

Low (20–45% RH)

Temp

2°C to 38°C

Pet safety

Toxic to pets

Mature size

60–100 cm tall and 60–90 cm wide (24–40 in × 24–36 in).

Care at a glance

Light

Aim for at least 4-6 hours of direct sun on the leaves. Requires full sun — a minimum of 6 hours of direct sunlight daily is needed to maintain compact growth and trigger repeat flowering; grow on a south-facing windowsill when kept indoors. If your only bright window faces south, that's perfect for jagged lavender — same window any aroid would fry on.

Watering

Watering jagged lavender: every 10–14 days in summer; every 3–4 weeks in winter. 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. Allow the growing medium to dry out between waterings; root rot develops rapidly in damp compost, particularly at lower temperatures.

Soil and pot

Jagged Lavender grows best in very free-draining, gritty or sandy loam, ph 6.5–8.0. Blend at least one-third coarse perlite or horticultural grit into potting compost; in the ground, plant on a raised bed or slope for guaranteed drainage. 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

Jagged Lavender sits happiest at around Low (20–45% RH) humidity and 2°C to 38°C (36°F to 100°F). Suits dry, airy conditions; persistently humid air in combination with cool temperatures leads to botrytis and stem base rot. Ventilate well when overwintering under glass. If you keep the room above 2°C to 38°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 jagged lavender sparingly. Feed monthly with a dilute, balanced liquid fertiliser from spring through early autumn; cease feeding entirely when overwintering under glass in cool conditions. 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 jagged lavender in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Frost damage and dieback — Even a brief frost below 0°C (32°F) blackens and kills soft growth; a hard frost kills the plant to the roots. Move containers under glass before the first autumn frost and maintain minimum 2–3°C overnight.
  • Botrytis (grey mould) when overwintering — In cool, poorly ventilated glass houses, grey mould develops on the fine foliage and stems during winter dormancy. Remove any dead or damaged material promptly and ventilate on mild days.

Propagation

Take 6–8 cm semi-ripe cuttings in late summer, root in a 50:50 mix of perlite and seed compost at 18–21°C. This species roots more readily from cuttings than from seed. 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

Jagged Lavender is toxic to pets. ASPCA lists Lavandula spp. as toxic to cats, dogs, and horses. The toxic principles linalool and linalyl acetate cause nausea, vomiting, and loss of appetite; essential oil from this genus is considerably more concentrated and therefore more hazardous than plant material. 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.

Jagged Lavender care — frequently asked questions

What is the common name for Lavandula pinnata?

Lavandula pinnata is most commonly called Jagged Lavender, but it is also known as Jagged lavender, Fern leaf lavender, Pinnate lavender. The names refer to the same species, so care instructions for Jagged Lavender apply identically to anything sold as Fern leaf lavender.

How much light does jagged lavender need?

Jagged Lavender grows best in direct sun (at least 4-6 hours). Requires full sun — a minimum of 6 hours of direct sunlight daily is needed to maintain compact growth and trigger repeat flowering; grow on a south-facing windowsill when kept indoors.

How often should I water jagged lavender?

Water jagged lavender every 10–14 days in summer; every 3–4 weeks in winter. Allow the growing medium to dry out between waterings; root rot develops rapidly in damp compost, particularly at lower temperatures. 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 jagged lavender toxic to cats and dogs?

Jagged Lavender is toxic to pets. ASPCA lists Lavandula spp. as toxic to cats, dogs, and horses. The toxic principles linalool and linalyl acetate cause nausea, vomiting, and loss of appetite; essential oil from this genus is considerably more concentrated and therefore more hazardous than plant material.

What USDA hardiness zone does jagged lavender grow in?

Jagged Lavender is rated for USDA zone 9-11 and RHS hardiness H2. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Jagged Lavender deep-dive guides

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

Featured in these plant shortlists

Jagged Lavender qualifies for 3 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Jagged Lavender is also known as Jagged lavender, Fern leaf lavender, and Pinnate lavender.