Rosemary Salvia rosmarinus

Reviewed June 2026 · how we check this

A woody, drought-tolerant Mediterranean evergreen with needle-like, resinous leaves and a piney, savory fragrance. Beloved for roasts, breads, and gardens alike, it thrives on neglect, sharp drainage, and full sun — and punishes overwatering and soggy feet faster than almost any other herb.

Light

Rosemary is a sun-loving Mediterranean shrub that wants 6–8 hours of direct sun a day — the more it gets, the more compact, aromatic, and oil-rich the foliage. In too little light it grows leggy and pale, loses its piney punch, and becomes far more prone to mildew and rot. Outdoors, plant it in the brightest, most open spot you have. Indoors it's genuinely demanding: even a bright south window is usually too dim through winter, so most indoor rosemary slowly declines without a grow light running 12–14 hours a day positioned close overhead. If yours is stretching toward the glass, it's begging for more sun.

Watering

This is where most rosemary dies — from too much water, not too little. Established plants are deeply drought-tolerant and want the soil to dry well between drinks; water deeply but infrequently, then let the top couple of inches go quite dry before watering again. In the ground, mature plants often need watering only in prolonged dry spells. Containers dry faster, so check by weight and finger-test rather than on a schedule. Yellowing from the bottom with damp soil signals overwatering and incipient root rot; dull, slightly wilted, drying tips mean it finally went too far the other way. Always err toward dry.

Soil & potting

Rosemary demands lean, gritty, sharp-draining soil and slightly alkaline conditions, roughly pH 6.0–7.5. Rich, moisture-retentive soil produces soft, rot-prone growth; this is a plant that thrives on poverty and grit. In beds, amend heavy clay heavily with coarse sand or fine gravel, or plant in a raised bed or mound for drainage. In containers, use a fast-draining cactus or succulent mix, or cut standard potting mix with plenty of perlite, pumice, or grit, in a terracotta pot with generous drainage holes. Terracotta is ideal — it wicks moisture away and helps prevent the soggy roots rosemary cannot tolerate.

Humidity & temperature

Rosemary prefers airy, breezy, low-to-average humidity and resents the stagnant, damp air that breeds powdery mildew, so give plants spacing and good airflow indoors and out. It's happiest between about 55–80°F. Most varieties are hardy only to Zones 8–10 and survive light frost but die back hard or perish in a deep freeze; in colder regions grow it in a pot to overwinter indoors, or seek out cold-hardy cultivars like 'Arp' or 'Hill Hardy.' When wintering indoors, keep it cool, bright, and well-ventilated — a chilly, sunny room suits it far better than a warm, dim, stuffy one.

Fertilizing

Rosemary is a light feeder that actively prefers lean soil, so go easy — heavy feeding produces soft, floppy, less-aromatic growth and invites problems. In the ground, an annual top-dressing of compost in spring is usually plenty. Container plants, whose nutrients flush away with watering, benefit from a balanced liquid fertilizer at half strength every 4–6 weeks through spring and summer only. Stop feeding entirely in fall and winter while growth slows. If the foliage looks lush, dark, and leggy rather than tight and silvery-green, you're feeding too much.

Pruning & maintenance

Regular pruning keeps rosemary bushy, productive, and from going woody and bare at the base. Harvest by snipping 4–6 inch tips of soft green growth — this doubles as pruning and encourages branching. Prune lightly and often through the growing season, taking no more than about a third at once, and always cut into green, leafy wood rather than the bare old wood, which is slow or unwilling to resprout. Shape after flowering in late spring. Hard renovation pruning of an overgrown, woody plant is risky, so shape gradually year to year instead of cutting back drastically.

Propagation

Rosemary is slow and erratic from seed, so most gardeners propagate from cuttings, which root readily and come true to the parent. Snip 4–6 inch tips of non-flowering new growth, strip the lower leaves, optionally dip in rooting hormone, and set in moist, gritty mix or a glass of water on a bright sill; roots form in 2–4 weeks. If you do start from seed, sow indoors 8–10 weeks before your last frost, barely cover, keep warm around 70°F, and be patient — germination is slow and spotty, often taking three weeks or more, with seedlings growing on slowly before they're ready to transplant out.

Common problems

Rosemary turning brown or dyingMost often root rot from overwatering or poor drainage — check the soil and roots first.→Powdery mildew (white powder on leaves)Usually damp, stagnant air and poor airflow — improve ventilation and ease off water.→

Through the year

Spring

Growth resumes — plant out after frost, refresh the topsoil with a little compost, take cuttings, and begin light tip-harvesting and shaping.

Summer

Peak growth and harvest. Water deeply but infrequently, harvest tips often to keep it bushy, and enjoy the flush of blue flowers.

Fall

Growth slows — ease back on water, stop feeding, and in cold regions pot up or bring tender plants indoors before hard frost.

Winter

Near-dormant. Keep it cool, bright, and well-ventilated; water very sparingly and never let it sit wet in cold, stuffy air.

Companion planting

Classic companions: cabbage, beans, carrots, and sage; its strong scent is said to deter cabbage moths, carrot flies, and bean beetles; pairs well with other dry-loving Mediterranean herbs like thyme and lavender.

Recommended supplies for Rosemary

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