Rosemary care guide: when & how to prune, fertilize and spray
Salvia rosmarinus · USDA zones 7–10
Woody Mediterranean herb. Like lavender, it hates wet roots and won't regrow from bare old wood. Bring containers inside in zone 6 and colder.
☀️ Sun
Full sun.
💧 Water
Low; let the soil dry between waterings.
🪱 Soil
pH 6.0–7.5. Sandy, very well-drained. Grit or gravel. No fertilizer.
How and when to prune rosemary
Shape after flowering
When: from the last spring frost to 4 weeks after.
- zones 6–7: about Apr 15 – May 13
- zones 8–10: about Feb 25 – Mar 25
Light shaping after the spring flowers keeps plants bushy.
- Cut back by up to one-third, always to just above healthy leaves.
- Never cut into the bare woody part.
Frost & winter protection for rosemary
Winter protection
When: from 2 weeks before to 1 week after the first fall frost.
- zones 6–7: about Oct 11 – Nov 1
Most rosemary dies below about 15–20°F (−9 to −7°C).
- Zone 7: plant against a south wall and cover with frost cloth on cold nights.
- Zone 6 or colder: pot it up and move it to a bright, cool window before the first frost.
Common rosemary problems and how to fix them
Powdery mildew indoors
Signs: White powder on leaves in winter.
What to do: More light and airflow; don't overwater.
Rosemary care FAQ
When should I prune rosemary?
Shape after flowering: from the last spring frost to 4 weeks after (around Apr 15 – May 13 in zones 6–7). Woody Mediterranean herb. Like lavender, it hates wet roots and won't regrow from bare old wood. Bring containers inside in zone 6 and colder.
What soil does rosemary need?
Sandy, very well-drained. Preferred pH 6.0–7.5. Grit or gravel. No fertilizer.
How much sun and water does rosemary need?
Sun: Full sun. Water: Low; let the soil dry between waterings.
What are common rosemary problems?
Powdery mildew indoors: White powder on leaves in winter. More light and airflow; don't overwater.
More herbs care guides
Timings are given relative to your average frost dates, with examples for typical US climates. Always read and follow product labels.