How to Prune, Propagate and Care for Rosemary
A rosemary plant is a little piece of the Mediterranean in your own garden or on your balcony. It smells wonderful as soon as you brush past it, stays green all year round and, with the right care, can live for many years. Yet many rosemary plants start to look bare and woody after a few years, or don't survive a wet winter.
In this guide you'll learn how to care for rosemary, when and how to prune it without leaving bare stems, how to grow new plants from cuttings and how to help your plant safely through winter. That way you'll always have fresh sprigs to hand for tea, hair rinses and fragrant rituals.
What does a rosemary plant need?
Rosemary (Salvia rosmarinus, formerly Rosmarinus officinalis) is an evergreen, woody shrub from the Mediterranean. There it grows on dry, sunny hillsides in poor, stony soil. The more closely you recreate those conditions, the happier it will be.
Sun: at least six hours of direct sun a day. In shade it becomes leggy and loses its scent.
Free-draining soil: rosemary hates wet feet. Heavy, waterlogged clay is its biggest enemy.
Shelter: a spot out of cold winds, such as against a south-facing wall, helps a lot in winter.
No pampering: too much water and feed make the plant weak. Rosemary likes things a little lean.
Rosemary in the garden or in a pot
In the garden
Choose the sunniest, most sheltered spot you have. If your soil is heavy, mix plenty of coarse sand or horticultural grit into it when planting, or plant the rosemary slightly raised, for example on a bank or in a raised bed. That way rainwater can drain away easily.
In a pot
In a pot, rosemary is easy to move, which is a big advantage in winter. Use a pot with a drainage hole, ideally terracotta, as it lets moisture evaporate. Fill it with compost for herbs or Mediterranean plants, mixed with some grit or perlite. Empty the saucer after rain or watering so the roots never sit in water.
If your plant outgrows its pot, repot it in spring into a pot one size larger.
Watering and feeding
Most rosemary plants don't die from drought, but from too much water. Only water when the top few centimetres of soil feel dry. A plant in the ground rarely needs extra water after its first year, except during a long, dry summer.
Plants in pots dry out faster. In summer you may need to water a few times a week; in winter, only very sparingly. Feeding is hardly necessary: a little organic herb feed in spring is plenty.
How to prune rosemary: when and how
Pruning rosemary keeps the plant compact, bushy and healthy. Without pruning, the stems grow long, turn woody at the base and you end up with a bare shrub that's only green at the tips.
When to prune rosemary
The best time for a proper prune is in spring, once the hard frosts are over, usually in March or April. The plant is starting to grow again and recovers quickly. A second, lighter trim can be done straight after flowering in late spring or early summer.
Avoid pruning late in autumn. Any new shoots that appear afterwards are vulnerable to frost. Snipping a few sprigs to use in autumn is no problem, though.
How to prune rosemary
Use sharp, clean secateurs so the stems are cut cleanly.
Cut the stems back to just above a pair of leaves or a side shoot. That's where the plant will grow back.
Remove no more than about a third of the plant at a time.
Never cut back into bare, brown wood. Always leave some green leaves on every stem, as rosemary rarely regrows from old wood.
Remove any dead, damaged or crossing stems right down to the base.
Good news: every time you harvest sprigs for tea or a hair rinse, you're already pruning a little. Snip off whole tips rather than pulling off individual needles, and the plant will stay nice and bushy.
Rejuvenating an old, woody rosemary
Has your plant become very woody? Rejuvenate it gradually, spread over two or three years. Each spring, cut back a few of the oldest stems to just above a green side shoot lower down the plant, and leave the rest. If it really won't recover, take cuttings from the young tips and start again. A new plant from your own cutting often grows into a lovely shrub within a year.
How to propagate rosemary from cuttings
Taking rosemary cuttings is easy and rewarding. From one plant you can quickly grow a handful more, for yourself or to give away.
When: from late spring to the end of summer. August is a great time, as the young shoots have firmed up a little but haven't turned truly woody yet.
What you need:
A healthy rosemary plant with young, non-flowering shoots
A sharp, clean knife or secateurs
Small pots or a seed tray
Cutting or seed compost, mixed with some sand or perlite
Optional: rooting powder and a clear plastic bag
How to take rosemary cuttings:
Cut a few tips of about 8 to 10 centimetres, just below a leaf node.
Strip the leaves from the bottom 3 to 4 centimetres of each cutting.
Dip the tip in rooting powder if you like. It works without, but it can help.
Push the cuttings a few centimetres deep into moist compost around the edge of the pot, and firm the soil gently.
Place the pot somewhere bright but out of harsh midday sun. A plastic bag over the top keeps the air humid; remove it now and then to let fresh air in.
Keep the compost lightly moist, but not wet.
Roots usually form after about four to eight weeks. You'll notice new growth, or slight resistance when you tug very gently. Then pot each one up separately.
You can also root rosemary in a glass of water. It's lovely to watch, but roots grown in water are often weaker and struggle once planted in soil. Cuttings in compost usually give stronger plants.
If you take cuttings late in summer, let the young plants spend their first winter somewhere bright and frost-free, and only put them outside in spring.
Helping rosemary through winter
In cooler, wetter climates such as the UK and the Netherlands, rosemary isn't fully hardy. It can often cope with a little frost, but the combination of cold and wet soil can quickly kill it. Young plants are especially vulnerable.
In the garden: make sure the soil drains well and the plant is sheltered. During hard frosts you can cover it temporarily with horticultural fleece. Remove it again when the weather turns milder.
In a pot: place the pot against a sheltered house wall, out of the rain, and wrap it in hessian or bubble wrap so the roots don't freeze. During prolonged hard frost, move it to a cool, bright, frost-free place, such as an unheated conservatory, greenhouse or a shed with a window.
Overwintering indoors: a warm living room isn't ideal. The air is too dry and too warm, which weakens the plant. Choose the coolest, brightest spot you have and water very sparingly.
Common problems
Yellow or brown needles: usually too much water, or a pot standing in water. Let the soil dry out and improve drainage.
Bare, woody base: the plant hasn't been pruned enough. Prune every spring from now on and rejuvenate it step by step.
Weak, thin stems: not enough sun. Move the plant to a sunnier spot.
Nibbled leaves and shiny beetles: this is probably rosemary beetle, a small, glossy green and purple beetle. Pick off the beetles and larvae, or shake the plant over a sheet of paper.
Dry, brown plant after winter: wait before you throw it away. Gently scratch a stem with your fingernail; if the wood underneath is green, the plant is still alive and may sprout again in spring.
Harvesting and using rosemary
You can harvest fresh sprigs all year round, as long as you never take more than a third of the plant at once. The scent and flavour are strongest just before flowering and on a dry, sunny morning.
Got more than you can use fresh? Read How to Dry Herbs at Home for ways to dry and store your harvest. With fresh sprigs you can make a fragrant rosemary tea, rosemary water for your hair or rosemary infused oil.
FAQs about pruning and growing rosemary
Can you cut rosemary back hard?
Preferably not. Rosemary rarely regrows from old, bare wood. Prune no more than a third of the plant at a time and always leave green leaves on every stem. Rejuvenate a very woody plant gradually over a few years.
When is the best time to prune rosemary?
In spring, once the hard frosts are over, usually in March or April. A light trim straight after flowering is fine too. Avoid pruning late in autumn.
Is rosemary hardy?
Not entirely. It can often tolerate a little frost, especially in dry, free-draining soil, but cold combined with wet roots is fatal. Plants in pots are more vulnerable and are best protected or moved somewhere frost-free during hard frosts.
Can you root rosemary cuttings in water?
Yes, you can, but cuttings in compost usually form stronger roots. If you want to try water, refresh it regularly and move the cutting into compost once it has a few centimetres of roots.
How long do rosemary cuttings take to root?
Usually four to eight weeks. New growth at the tip is a good sign that roots have formed.
Why is my rosemary turning brown?
The most common cause is overwatering or poor drainage, which makes the roots rot. Hard frost, drying out indoors or too dark a spot can also cause brown needles.
Should rosemary come indoors in winter?
A plant in the ground can usually stay outside in a sheltered, dry spot. Move a potted plant to a cool, bright, frost-free place during hard frosts. A warm living room is usually too warm and too dry for rosemary.
Discover more about rosemary
With a little sun, free-draining soil and a yearly prune, you'll enjoy your rosemary plant for years. Want to explore more of what you can do with this versatile herb? Read on:
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