USDA Zone 12 is frost-free year-round, with average winter lows of 50 to 60°F. There is no last spring frost and no first autumn frost to plan around, so Zone 12 gardeners plant by heat and by the wet and dry seasons instead of by frost dates. The tropical warmth that lets heat lovers grow all year makes cool-season crops much harder. Frost dates here are zone averages and vary by microclimate, elevation and year — check your local extension service for guidance for your exact spot.

Rosemary is the toughest Mediterranean perennial in Zone 12 — a woody, fragrant shrub that loves sun and hates wet feet. In frost-free Zone 12 it grows year-round and can live for years, but tropical humidity and heavy rain are its enemies: rosemary dies fast in soggy soil. The secret is sharp drainage — a raised bed, a slope, or a pot with gritty mix — and watering little and often not at all once it is established. Get the drainage right and rosemary is nearly indestructible.

Zone 12 at a glance

Zone 12 is frost-free year-round, with average winter lows of 50 to 60°F. Plant by the season: the coolest, driest months for cool-season crops, and the cooler part of the year for the best fruit set on heat lovers.

Detail Zone 12 guidance
Average winter low 50 to 60°F
Last spring frost None — frost-free year-round
First autumn frost None — frost-free year-round
Days to germination 14–28 days
Days to maturity 90–120 days
Sowing start indoors
Best planting window Year-round; best in the drier months
Harvest 90–120 days after sowing/transplanting
Sun full sun
Soil pH 6.0–7.0
Spacing 24–36 inches
Water needs low
Cold tolerance tender

When to plant rosemary in Zone 12

Plant rosemary any time of year in Zone 12, with the best results at the start of the drier months, when a young plant can establish roots without sitting in wet soil. Buy a small plant rather than starting from seed: rosemary seed germinates slowly, in 14–28 days, and seedlings grow slowly too, taking 90–120 days to reach picking size. A bought plant gives you usable leaves within weeks. Rosemary is a perennial, so one well-placed plant can last for years — choose its spot with care, because it grows into a woody shrub. The planting calendar hub shows the Zone 12 year at a glance, and the January guide covers the cooler, drier part of the year.

Starting rosemary in Zone 12

Start rosemary from a bought plant or a cutting, not seed, unless you are patient. Cuttings root readily in gritty mix: take a few inches of non-flowering stem, strip the lower leaves, and push it into moist, sandy mix. Plant out at 24–36 inches apart in the sunniest, best-drained spot you have — a raised bed or a large pot with added grit or perlite. Never plant rosemary in a low, wet corner or in heavy clay that stays soggy after rain. Water the young plant in, then water sparingly: rosemary would rather be dry than wet.

Soil, spacing, sun and water

Rosemary grows best in full sun, in soil with a pH of 6.0–7.0, spaced 24–36 inches apart. Dig in compost before planting and mulch lightly to hold moisture. Give plants room so air moves between them — in Zone 12 humidity, airflow is the best defence against leaf diseases. This crop has low water needs: water sparingly and let the soil dry between waterings. Overwatering is a far bigger risk than underwatering in Zone 12, so when in doubt, wait a day. Keep the bed weed-free, and feed lightly with compost rather than heavy fertiliser, which pushes soft, disease-prone growth. The potting-mix calculator can work out quantities for your bed.

Companion planting

Good companions for rosemary include tomatoes, peppers, marigolds, cabbage. The companion planting finder can suggest combinations for your whole garden. Rotate crops each year and avoid planting where the same family (Lamiaceae) grew last year. A related crop to plan alongside is thyme, which shares the Zone 12 calendar, so the two guides work well together.

Pests and problems

The common pests and problems to watch for with rosemary are aphids, spider mites, whiteflies. Inspect plants regularly, especially leaf undersides, and act early: hand-pick larger pests, wash aphids off with water, and remove badly affected leaves. Healthy plants in the right soil and spacing resist pests better than stressed ones. Fungal problems are the bigger worry in Zone 12 humidity: water at the base, space widely, and mulch to stop soil splashing onto leaves. If you are unsure what you are looking at, the pest identifier helper can narrow it down.

Harvest and storage

Start picking rosemary once the plant is established, about 90–120 days after sowing a seed plant, or within weeks of planting a bought plant. Snip sprigs as needed, taking the tips of young stems, and never cut more than a third of the plant at once. Pick in the morning, when the oils are strongest. Fresh sprigs are best for roasting and grilling; rosemary also dries beautifully — hang small bunches in a dry, airy spot and store the stripped needles in a jar. Prune lightly after flowering to keep the plant bushy, and never cut into old, bare wood, which does not regrow.

Frequently asked questions

When should I plant rosemary in Zone 12?

Any time of year, best at the start of the drier months. Zone 12 is frost-free year-round with winter lows of 50 to 60°F, so plant by rain, not frost. Check your local extension service for your area.

Why did my rosemary die in Zone 12?

Almost always wet feet. Rosemary hates soggy soil and tropical rain can rot its roots. Plant in a raised bed or pot with sharp drainage and water sparingly.

How long does rosemary take to grow in Zone 12?

Seed germinates in 14–28 days and plants take 90–120 days to reach picking size. Buy a plant or take cuttings for much faster results.

Does rosemary need much water in Zone 12?

No — it has low water needs. Water a young plant while it establishes, then water sparingly. Overwatering kills more rosemary than drought does.