Overview
What rosemary needs, how hardy it is, and whether it suits your garden.
Rosemary is an evergreen shrub from dry Mediterranean hillsides, so it wants sun, warmth and free-draining soil, and little else. Harsh frost and cold winds can damage it, and cold, wet roots do. Trim it lightly after flowering to keep it bushy, pick sprigs any time of year, and root a few cuttings every so often to replace woody old plants.
Quick facts
- Botanical name
- Salvia rosmarinus
- Soil pH
- 6.5 – 7.0
- Feeding
- Light feeder
- Hardiness
- USDA zone 8a and warmer
- Height
- Up to 180 cm (71 in)
- Propagation
- Cutting, Layering, Seed
Survives −12 °C
Growing details
- Spacing
- 45 cm (18 in)
- Frost sensitivity
- Frost hardy
Growing calendar
- Plant out: April, May, September, October
- Flowering: March, April, May, June
- Prune: May, June, July
- Propagate: May, June, July, August
- Harvest: January, February, March, April, May, June, July, August, September, October, November, December
Best in spring as the soil warms (RHS); autumn also works on well-drained soil (Gardeners’ World). Spring into early summer; potted plants overwintered indoors flower later (Penn State). A light trim after flowering; never into old wood (RHS). Cuttings of new growth from late spring into summer (RHS, UW-Madison). All year; best flavour from soft new growth in late spring and summer (RHS).
Is this plant right for you?
- Evergreen
- Drought tolerant
- Needs drainage
- Pick all year
- Good in pots
- Loved by bees
- Safe for pets
Good to know
It does well in a pot indoors or out, so you do not need a bed for it. It stands frost, so it can go out earlier than tender crops.
Before You Grow
Choose an upright, trailing or hardier variety, and the sunniest, best-drained spot you have.
Rosemary is non-toxic to cats, dogs and horses (ASPCA).
What you need
A young plant
Quicker than seed. See choose your rosemary.
Full sun
Warm and sheltered. See where rosemary grows best.
Grit
For heavy soil and pots. See soil.
A pot with drainage holes
In cold regions, essential. See containers.
Secateurs
For the yearly trim. See pruning.
Choose your rosemary
Varieties differ in habit, flower colour, flavour and hardiness (RHS).
Upright varieties suit hedges and borders: ‘Miss Jessopp’s Upright’ (RHS AGM), ‘Tuscan Blue’, ‘Majorca Pink’.
Trailing (prostrate) varieties arch or creep, and suit walls, pots and hanging baskets: ‘Foxtail’ (RHS AGM), ‘Prostratus’, ‘Lockwood de Forest’.
Flower colour. Most are blue; ‘Rosea’ (RHS AGM) and ‘Majorca Pink’ are pink; ‘Lady in White’ is white.
Hardier. ‘Arp’ and ‘Madalene Hill’ (‘Hill Hardy’) are hardy to about USDA zone 7, or 6 with protection (UW-Madison, Penn State).
Buying. Plants are sold year-round. Buy UK-grown plants in Britain: rosemary is a high-risk host for the bacterial disease Xylella fastidiosa (RHS).
Rosemary varieties compared
-
‘Miss Jessopp’s Upright’
- Habit
- Tall, upright
- Flowers
- Light blue
- Note
- RHS AGM; good hedge
-
‘Foxtail’
- Habit
- Semi-trailing dome
- Flowers
- Pale blue
- Note
- RHS AGM
-
‘Rosea’
- Habit
- Upright
- Flowers
- Pale pink
- Note
- RHS AGM
-
‘Prostratus’
- Habit
- Creeping, 15 to 30 cm (6 to 12 in)
- Flowers
- Dark blue
- Note
- Long flowering
-
‘Arp’
- Habit
- Upright, 0.9 to 1.2 m (3 to 4 ft)
- Flowers
- Light blue
- Note
- Hardy to zone 7a
-
‘Madalene Hill’
- Habit
- Rounded, about 90 cm (3 ft)
- Flowers
- Blue
- Note
- Hardy to zone 7a
From the RHS and UW-Madison. In a cold garden, grow a hardier variety or keep it in a pot.
Where rosemary grows best
Rosemary wants full sun, warmth and shelter (RHS, Gardeners’ World).
Hardiness. A perennial shrub in USDA zone 8 and warmer (Penn State, Illinois). In the UK, established plants survive about −8 °C (18 °F) (RHS); UMD gives −15 °C (5 °F). Harsh frost and cold winds damage it, and in colder regions it is grown in a pot and brought in for winter.
Cold and wet together kill young plants, even where they’re hardy (Gardeners’ World).
Tolerances. Drought, salt and coastal sites once established; not clay or humid, wet conditions (NC State).
Size. Upright plants reach 0.9 to 1.8 m (3 to 6 ft) (UMD).
- Sun
- Full sun
- Hardy to
- About −8 to −12 °C (18 to 10 °F)
- Soil pH
- 6.5 to 7.0
Soil
Light, free-draining soil, sandy or gravelly (RHS, Penn State). Rosemary hates wet roots, especially in winter.
Heavy clay. Dig in bark, grit or leaf mould (Gardeners’ World), or grow it in a raised bed or pot (RHS).
pH. 6.5 to 7.0 (Penn State, UMD); NC State says slightly acid is fine.
Fertility. Rosemary thrives in poor soil and needs no feeding in the ground (RHS).
Mulch with gravel or sand, which dries quickly, rather than moisture-holding organic mulch (Penn State). Gardeners’ World mulches with leaf mould or compost in autumn; on heavy, wet soil, gravel is the safer choice.
Planting
Plant in spring, shallowly, into gritty soil or a well-drained pot.
Plant shallowly: the top of the root system only lightly covered (RHS).
When to plant rosemary
The best time is spring, once the soil starts to warm (RHS). Plants are sold all year and can go in at almost any time; Gardeners’ World also plants in autumn.
In cold, wet gardens, grow young plants in a pot for a couple of years before planting them out (Gardeners’ World).
Where rosemary isn’t hardy, set pots out after the danger of frost has passed, and bring them in two to three weeks before the first autumn frost (Penn State).
- Spring, as the soil warms.
- Young plants in pots first on cold, wet sites.
- In cold regions, pots out after frost.
How to plant rosemary
Drainage decides whether rosemary survives its first winter.
-
Pick the spot
Full sun, sheltered, light and free-draining (RHS).
-
Improve heavy soil
Dig in grit, bark or leaf mould, or plant in a raised bed (Gardeners’ World, RHS).
-
Plant shallowly
The top of the root system only lightly covered with soil (RHS).
-
Space it
At least 45 cm (18 in) between plants, including in a hedge (RHS, Gardeners’ World).
-
Water in
Then water in dry spells through the first year (RHS).
Planting and potting on in containers
Rosemary grows big, so potted plants need moving on every couple of years (Gardeners’ World).
-
Choose the pot
At least 30 cm (1 ft) wide and deep with plenty of drainage holes (RHS). Clay pots dry out quickly, which suits it (Penn State).
-
Mix the compost
Peat-free soil-based compost with up to a quarter grit by volume, and crocks in the base (RHS, Gardeners’ World).
-
Plant at the same depth
Firm in lightly and water.
-
Move up a size
Every couple of years, into fresh compost (Gardeners’ World). A slightly pot-bound plant flowers better (UW-Madison).
Care
Water only while it establishes, trim after flowering, and keep winter wet away.
Overwatering is the most common cause of decline and death (UW-Madison, NC State).
Care by season
Spring
Plant: as soil warms
Enjoy the flowers. See growing conditions.
After flowering
Cuttings: from new growth
Trim lightly. See pruning.
Summer
Harvest: best flavour
Water pots in dry spells. See watering.
Autumn
Mulch: gravel, not compost
In cold regions, bring pots in. See overwintering.
Winter
Cold snap: cover with fleece
Keep roots out of the wet. See containers.
Watering rosemary
Rosemary is drought tolerant once established, and overwatering kills more plants than anything else (RHS, UW-Madison).
New plants. Water in dry spells during the first year (RHS).
Established plants in the ground shouldn’t need watering (RHS).
Pots dry out quickly in hot, sunny weather: water in dry spells, letting the compost dry slightly between waterings, and never let it get waterlogged (RHS, Penn State).
Feeding rosemary
In the ground, rosemary needs no feeding and thrives in poor soil (RHS). Illinois finds regular feeding gives the most leaf for harvesting.
In pots, a sprinkling of general granular feed in late spring or early summer once a plant has been in the same pot for over a year (RHS).
Go lightly. Too much fertiliser reduces flowering and fragrance (UW-Madison).
Pruning rosemary
Trim lightly every year after the flowers fade to keep plants compact and bushy (RHS).
Not into old wood. Rosemary rarely regrows from bare, woody stems, so keep cuts within leafy growth (RHS).
Young plants. Pinch the tips to make them branch (UW-Madison, UMD).
Hedges. Trim upright varieties after flowering in early summer; Gardeners’ World keeps a ‘Miss Jessopp’s Upright’ hedge about 60 cm (2 ft) tall.
Old, leggy plants don’t recover from hard pruning. Replace them from cuttings every seven or eight years (RHS).
- After flowering.
- Only into leafy growth.
- Replace woody plants.
Rosemary in containers
Rosemary does well in pots, which give it the drainage it likes (RHS). In cold regions, it’s the way to grow it (UW-Madison, Illinois).
Winter wet. Cold, wet compost rots the roots. Move pots to a rain shadow near a building in wet winters (RHS).
Winter cold. Roots in pots can freeze. Group pots, wrap them, or move them to a porch, greenhouse or the shelter of a wall (RHS).
Summer outdoors. Stand the pot outside, or sink it rim-deep in the border so there are no roots to disturb when it comes in (UW-Madison).
Overwintering rosemary indoors
Where rosemary isn’t hardy, bring it in for winter. It can be tricky indoors, from too little light and too much or too little water (Penn State).
When. Two to three weeks before the first autumn frost (Penn State). Plants dug from the garden transplant badly, so grow them in pots all year (Illinois).
Where. A cool, even cold, sunny spot: a south-facing window or supplementary lights, with good air circulation (Illinois, Penn State).
Humidity. Indoor air dries the leaves. Stand the pot on a tray of wet pebbles; don’t water more to compensate (Illinois).
Water sparingly, letting the compost dry slightly between waterings; it grows little in winter (Illinois, Penn State).
In spring, move it back outside once frost is over.
Problems
Waterlogging and hard cold are the usual troubles; rosemary beetle in the UK, and indoor pests under glass.
Common rosemary problems
Wet roots and hard cold cause most rosemary deaths.
Browning, dying plant
- Overwatering
- Root rot
Waterlogged soil, especially in winter (RHS, UW-Madison). Improve drainage; in pots, water less. See watering.
Brown tips indoors
- Dry air
- Root rot
Dry indoor air, or root rot from overwatering (Illinois, Penn State). See overwintering.
Frost-scorched shoots
- Cold
- Wind
Harsh frost and cold winds. Cover with fleece or hessian in cold spells (RHS).
Leggy, bare at the base
- No pruning
- Old plant
Unpruned or aged plants. Trim yearly; replace old plants (RHS). See pruning.
Knobbly growths on old stems
- Normal
Adventitious roots on older plants. Harmless (UMD).
More problems with rosemary
Common pests
Rosemary beetle
Small metallic green and purple striped beetles and their larvae eat the leaves; look under leaves from early autumn to spring. Usually not serious (RHS, Gardeners’ World).
Indoor pests
Aphids, spider mites, mealybugs, scale and whitefly, mainly on plants kept indoors (UW-Madison, NC State).
Common diseases
Root rot
From wet soil or overwatering; deadly outdoors and especially in pots overwintered indoors (Penn State).
Powdery mildew
Worse with poor air circulation and high humidity. Space plants for airflow (Penn State, NC State).
Harvest & Use
Snip sprigs all year; soft summer growth has the best flavour.
Harvesting rosemary
Rosemary is evergreen, so you can pick it all year, but the soft new growth of late spring and summer has the best flavour (RHS).
How. Snip shoots or pull small sprigs from the main stem, keeping the plant’s shape (RHS, Gardeners’ World). Take larger branches with secateurs for roasting.
How much. No more than about a fifth of the plant at a time (UW-Madison).
For drying, cut before the plant flowers (UW-Madison, Penn State).
- All year.
- Soft new growth tastes best.
- No more than a fifth at once.
Drying, storing and using rosemary
Drying. Hang bundles upside down somewhere warm, dark and airy. Once dry, strip the leaves and keep them in an airtight jar (RHS, UW-Madison).
Freezing. Penn State freezes finely sliced leaves in a bag or ice-cube tray; Gardeners’ World finds rosemary doesn’t freeze well. Drying is the more reliable way.
Cooking. Rosemary is strong: use it sparingly with lamb, pork, poultry, fish, potatoes and roasts, and in oils and vinegars. Strip the leaves from the woody stems, or use sturdy stems as skewers (Gardeners’ World, Illinois).
Propagation
Cuttings root readily; seed is slow.
Propagating rosemary
Cuttings are the best way: they root easily and keep the variety true (UW-Madison, Illinois).
Cuttings. In late spring to early summer, take 10 to 15 cm (4 to 6 in) tips of non-flowering shoots. Strip the lower leaves, dip in rooting hormone if you like, and insert into perlite or a gritty, free-draining mix (UW-Madison, Penn State). They root in 10 to 20 days with gentle bottom heat at 21 to 24 °C (70 to 75 °F) (Penn State).
Layering. In spring or autumn, peg a low stem into the soil to root. It often happens naturally: look for rooted stems around the edge (RHS).
Seed germinates slowly and unevenly, takes up to three years to make a usable plant, and doesn’t come true for named varieties (UW-Madison).
More to Explore
Quick answers, guides that pair well with rosemary, and the sources behind this one.
Frequently asked questions
Why is my rosemary dying?
Usually wet roots. See common problems.
How do I prune rosemary?
Trim lightly after flowering, only into leafy growth. See pruning.
Can rosemary survive winter outside?
In USDA zone 8 and warmer, and most of the UK, if the soil drains well. Elsewhere, bring pots in. See overwintering.
How often should I water rosemary?
Established plants in the ground rarely need it; water pots when the compost has dried slightly.
Can I grow rosemary indoors?
For winter, in a cool, bright window. See overwintering.
How do I grow rosemary from cuttings?
Take 10 to 15 cm (4 to 6 in) tip cuttings in late spring or early summer. See propagation.
Is rosemary safe for cats and dogs?
Yes, the ASPCA lists it as non-toxic to cats, dogs and horses.
How long does a rosemary plant last?
Many years, but the RHS suggests replacing it every seven or eight years as it turns woody.
Related guides
Sources
- How to grow rosemary (opens in a new tab) Royal Horticultural Society
- Rosemary (opens in a new tab) ASPCA Animal Poison Control
- Rosemary, Salvia rosmarinus (opens in a new tab) University of Wisconsin-Madison Extension
- Herb garden plants: rosemary (opens in a new tab) Penn State Extension
- Rosemary (opens in a new tab) University of Illinois Extension
- Salvia rosmarinus (opens in a new tab) NC State Extension Gardener Plant Toolbox
- Rosemary (opens in a new tab) University of Maryland Extension
- How to grow rosemary (opens in a new tab) BBC Gardeners’ World