Herb · Lamiaceae
Rosemary
Salvia rosmarinus
Plant this tough, fragrant Mediterranean herb, give it sun and grit, and it pays you back with sprigs for the kitchen all year.
Full sun
Every 7–14 days
USDA 7–11
2–6 ft · 0.6–1.8 m
Overview
Rosemary is one of the most rewarding herbs a grower can plant. This woody evergreen comes straight off the sun-baked hills of the Mediterranean, and it grows like it means it, fast and fragrant once it gets what it wants. It rides in the mint family, but skip the rich, damp soil its cousins love, because this one thrives on sun and grit.
Get it settled and rosemary keeps going as a perennial that returns year after year, stacking up woody stems packed with narrow, needle-like leaves. Small blue flowers, and now and then pink or white, break out from late winter into spring. Gardeners in zones 7 through 11 can grow it outdoors all year, and colder growers just move a pot inside to keep the run going.
The best part is how much it gives for how little it asks. Overwatering, not neglect, is the one thing that trips it up, so plant it lean and water it sparingly and it takes off. Nail that single habit, and rosemary rewards you with fragrant harvests season after season.
Care
The short version: load it up with sun, plant it in fast-draining soil, and water only once the soil has dried well down. Feed it lightly, keep the air moving, and hold it on the dry side, and this herb keeps producing all year.
Light
Rosemary runs on full sun and thrives on 6 to 8 hours a day, so the brighter the spot the better it grows. Part shade will keep it ticking over, but the growth turns thin and leggy and the flavor slips. Indoors, park it in the brightest window and watch it perk up.
Water
Watering is where rosemary makes or breaks, so a light hand wins every time. Let the top half of the soil dry out before the next drink, around every 7 to 14 days, and back off further once it hits its stride. Soggy roots are the one real threat, so when in doubt, hold off.
Soil
Rosemary takes off in light, sandy, fast-draining soil, the grittier the better. It shrugs off poor, rocky ground but rots in heavy clay, so dig in grit or sand if your soil hangs onto water. A pH of 6.5 to 7.0, right around neutral, keeps it charging along.
Temperature
Rosemary powers through a wide range, from about 10°F to 86°F (-12°C to 30°C), though cold tolerance swings by cultivar. A hard freeze can knock out the tender types, so in cold zones grab a hardy selection or move pots indoors to keep the plant rolling into spring.
Humidity
It thrives on dry air, around 30% to 50% humidity, straight in line with its dry-country roots. Damp, stagnant air is what kicks off powdery mildew, so airflow does far more for it than any moisture you could add.
Feeding
Rosemary is a light feeder that hits peak flavor when kept a little hungry. One modest dose of balanced fertilizer or compost in spring fuels it for the whole year. Pour on more and you trade that great fragrance for soft, sappy growth, so easy does it.
Pruning
Trim lightly after flowering and keep harvesting sprigs through the season, and rosemary bushes out full and shapely. Stick to one hard line: steer clear of cutting into old leafless wood, which is slow to sprout again and may not bounce back, so stay in the green growth.
Repotting
Bump a potted rosemary up a size every 1 to 2 years, or the moment roots circle the pot, water rushes straight through, or new growth stalls. Reach for a gritty, fast-draining mix and a pot with real drainage holes to keep it surging.
Size & spacing
24–71 in (60–180 cm) tall
When to plant
Rosemary grows on its own unhurried clock, and it pays to work with it. Seed started indoors in late winter is a gamble, so most growers get a head start by setting out plants once spring frost clears. In mild climates the harvest keeps rolling all year, and small blue flowers spark up from late winter into spring.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 10-12 weeks before last spring frost (germination is slow and erratic)
- Plant: after danger of frost has passed in spring
- Harvest: Small blue (occasionally pink or white) flowers in late winter to spring; leafy sprigs can be harvested year-round in mild climates.
Hardiness
USDA hardiness zones: 7–11
Temperature: down to -18°C
Troubleshooting
Just about every rosemary problem traces to one of two things: too much water at the roots or too little air around the leaves. Spot the early signs and you can jump in before the plant slides. Track down your symptom below and act while it still turns things around.
A plant wilting and yellowing even with wet soil
When rosemary flops in soggy soil, thirst is not the story, it is root rot from overwatering or poor drainage. Dig down and you will hit soft, brown roots giving off a sour smell. Cut the watering, repot into a gritty, fast-draining mix, and pull a few healthy cuttings as a backup in case the plant does not make it.
Fix:
- Stop watering and allow soil to dry
- Repot into fast-draining gritty mix and trim rotted roots
- Take healthy stem cuttings as a backup if the plant is failing
Fine webbing and a dull, speckled look to the leaves
Faint webbing and pale stippling flag spider mites, which hammer indoor and stressed plants hardest in dry winter air. Flip a leaf and you will catch the tiny mites scurrying through the threads. Blast the foliage with water, hit it with insecticidal soap or horticultural oil, and get more air moving to shut them down.
Fix:
- Rinse foliage with a strong stream of water
- Apply insecticidal soap or horticultural oil
- Increase airflow and reduce plant stress
Brittle brown stems dropping leaves after a hard winter
Bare, snappy wood after a cold snap is winterkill, and it lands hardest on tender cultivars in marginal zones. Scratch the bark for the verdict: green underneath means alive, dry and brown means done. Cut the dead stems back to living tissue in spring and let the plant fire out fresh growth from what pulled through.
Fix:
- Prune out dead wood back to living tissue in spring
- Allow plant to regrow from healthy stems
A dusty white film spreading over the leaves
That powdery white layer is powdery mildew, a fungus that moves in the moment the air goes still. It pops up most on crowded indoor rosemary stuck in stale winter air. Open up the spacing, drop the humidity, and strip off the worst-coated leaves, and the plant bounces right back.
Fix:
- Improve air circulation and spacing
- Reduce humidity and avoid overhead watering
- Remove and discard affected foliage
Toxicity
Growing rosemary around pets or kids? Great news: it is non-toxic through and through. The ASPCA clears it as safe for cats, dogs, and horses, and the same herb goes straight from the garden to your plate. The only thing to set aside is the concentrated essential oil, a separate product that is not for eating.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Rosemary is safe for cats, and the ASPCA lists it among its non-toxic plants. A curious nibble does zero harm, though most cats steer clear of the strong scent anyway.
Dogs None
Dogs can chew the leaves without a hitch, and the herb even shows up in some pet foods as a natural preservative. Only a really big helping might spark a mild, passing stomach upset.
Horses Safe
Horses can graze rosemary safely. The aromatic foliage is no favorite, so they rarely take more than a taste.
Rabbits Safe
A little fresh rosemary works for rabbits as part of a varied diet. Keep hay and greens as the bulk of the menu, with the herb as an extra.
Livestock Safe
Goats, sheep, and cattle can browse rosemary with zero ill effect. Those pungent leaves keep most stock from eating much of it anyway.
Birds Safe
The herb poses no danger to backyard hens or pet birds. Toss a sprig in the run and it is harmless, even if it mostly gets ignored.
People Safe
Rosemary is a kitchen powerhouse, safe to cook with and eat for adults and children alike. The one thing to keep apart is the concentrated essential oil, a different product and not for eating.
Highly concentrated rosemary essential oil is a separate product that can irritate skin or be harmful if ingested in quantity, but the culinary herb and growing plant are non-toxic.
Varieties
Rosemary offers plenty to choose from, from low trailing mats to bold upright shrubs, and a few cultivars really earn their spot when you are picking for tough winters or for the kitchen.
Arp
One of the toughest cultivars in the cold, powering through winters that would flatten most rosemary.
Hill Hardy
An upright, cold-tough selection that keeps charging in marginal northern zones where most rosemary gives out.
Tuscan Blue
A vigorous upright grower with deep blue flowers, a favorite both for cooking and for clipping into crisp low hedges.
Prostratus
A low, trailing groundcover form that spills fast over walls and pots, though it takes cold less well than the upright types.
How to propagate
Stem cuttingsEasy
Spring to summer from softwood or semi-ripe growth · 4-8 weeks to root
Cuttings are the fastest, surest way to multiply your rosemary, and most growers run with them. In spring or summer, snip 8 to 15 cm pieces of soft or half-ripe growth, strip the lower leaves, and drop them into a gritty, well-drained mix, where they root in 4 to 8 weeks.
SeedDemanding
Indoors 10-12 weeks before last frost · Several weeks to germinate, then a full season to establish
Seed is the long game, and it tests your patience. Sow indoors 10 to 12 weeks before the last frost and brace for slow, scattered sprouting and a low strike rate, with weeks to germinate and a full season before plants establish. That is exactly why most growers grab cuttings instead.
Myths
Rosemary needs frequent watering to stay healthy.
Once it settles in, rosemary powers through drought and barely wants a drink. Soggy soil takes out far more plants than any dry spell, so a light, sparing hand is the winning move every time.
The rosemary plant is toxic to pets because rosemary oil can be harmful.
You can plant it around pets without a second thought. The ASPCA lists the growing plant and culinary herb as non-toxic to cats, dogs, and horses. Only the concentrated essential oil, a separate product, carries any irritation risk, and that is not what a pet runs into in the garden or on the plate.