Rosemary
迷迭香 Salvia rosmarinus · Lamiaceae
A Mediterranean shrub that usually dies of wet roots, not cold: give it sharp drainage, sun, and a prune that stays in the green.
The winter wet problem
Rosemary comes from dry scrub and rocky ground, and PFAF describes it on well-drained soils in full sun (PFAF). In a wet winter, the root ball can sit in saturated soil for weeks. The plant may look alive in autumn and collapse in spring. Drainage is the first design decision, not hardiness.
On clay, do not plant straight into the border and hope. Use a raised bed, a mound of gritty compost, or a large pot with a drainage hole and feet. A sheltered wall helps in cold areas, but it will not save a waterlogged root. If the site holds water after rain, choose another plant.
| Site | What happens | Best choice |
|---|---|---|
| Open clay border | Roots stay wet in winter | Raised bed or mound |
| Free-draining bank | Roots dry quickly | Plant in the ground |
| Large pot | Drainage controlled; roots confined | Gritty mix; raise on feet |
| Sheltered wall | Warmth and wind protection | Only with good drainage |
Growing it
Give rosemary full sun and a lean, gritty soil. Water young plants to establish, then only in severe drought. Overfeeding produces soft growth that winter kills. In cold climates, choose a sheltered wall and take cuttings in late summer as insurance.
Prune after flowering, cutting back to a green sideshoot rather than into bare old wood. Rosemary can be trained as a loose hedge or a standard, but it resents hard renovation. Replace leggy plants from cuttings rather than trying to force old wood to resprout.
Harvest and drying
Pick sprigs year-round, but avoid heavy cutting in winter when growth is slow. The main harvest is in spring, before flowering, when the oil content is high. Use sharp scissors and take the soft new growth.
Rosemary dries well. Bundle the sprigs and hang them in a dark, airy place, or lay them on a rack. Once dry, strip the needles and store them in an airtight jar. The woody stems can be used as skewers for grilling.
- Take soft new growth in spring.
- Bundle and dry in the dark.
- Strip the needles when crisp.
- Store airtight; use stems as skewers.
Identifying it
Rosemary has narrow, needle-like leaves with rolled edges, woody stems and small blue, white or pink flowers. The scent is resinous and pine-like. It is now classified as Salvia rosmarinus, though many nurseries still label it Rosmarinus officinalis.
Do not confuse it with other needle-leaved shrubs, especially in a wild or unlabelled setting. The scent is a good confirmation, but it is not a licence to use an unknown plant internally.
Traditional context
Rosemary has a strong cultural history in Europe as a symbol of remembrance, and it is a well-established culinary herb. The essential oil is used in aromatherapy and topical products, where concentration and dilution matter.
PFAF warns that rosemary oil can redden and irritate skin, and that large quantities have been used as an abortifacient with dangerous effects. Culinary use is a different question from concentrated oil; this page gives no dose or treatment plan.
Cautions
Safety notes for rosemary
- Essential oil should not be swallowed without qualified guidance; it is toxic in large amounts.
- Products containing rosemary oil can cause skin redness and irritation; dilute before topical use and stop if you react (PFAF).
- PFAF warns that large quantities have been used as an abortifacient and can cause serious harm; avoid concentrated products in pregnancy.
- Avoid medicinal doses during breastfeeding unless a qualified clinician advises otherwise; data are limited.
- If you have epilepsy or take seizure medication, ask a clinician before using concentrated rosemary products.
- This is horticultural information, not medical advice or a dose recommendation.
A starting point for a conversation with a qualified practitioner or pharmacist — not a diagnosis, dose or treatment plan. See the full safety page.
Questions this plant raises
Why is my rosemary turning brown?
Usually waterlogging or root rot. Rosemary hates wet feet. Improve drainage, reduce watering, and check the roots for rot.
Can rosemary survive winter outdoors?
In zone 7 and warmer, yes, in a sheltered, free-draining spot. In colder areas, grow it in a pot and move it under cover.
How do I propagate rosemary?
Take 10 cm cuttings of non-flowering shoots in late summer, strip the lower leaves, and root them in gritty compost.
Sources & further reading
- Plants for a Future — Rosmarinus officinalisPFAF
- NC State Extension — Salvia rosmarinus (Rosemary)NC State Extension
Accessed for horticultural and safety context. Traditional-use statements are historical and are not evidence of effectiveness. Written and edited by the Herb Ledger editorial team. Read the editorial policy.
More leaves & stems
