USA plant library · herb

Rosemary

Salvia rosmarinus (Rosmarinus officinalis) · Lamiaceae

Evergreen culinary herb; used as a hedge in warm regions

Photo: Miguel Angel Masegosa Martínez, CC BY 2.0, via Wikimedia Commons

Sun: Full sun
Soil: Sharply drained, sandy soil. Dislikes wet feet
Soil pH: Prefers about 6.0-7.0; tolerates a wider range, from acid soil up to 7.5
Water: Low; drought-tolerant once established
Hardiness: USDA zones 8-10. Hardiness varies: in cooler areas use hardy cultivars such as 'Arp' or 'Hill Hardy', and overwinter indoors further north
Height and spread: 3-4 ft x 3-4 ft. Upright forms 4 ft or more; prostrate forms low

Guv's tipRosemary dislikes wet feet, so give it sharply drained, sandy soil. Trim lightly after flowering, but avoid cutting into old wood.

Through the year

Spring after frost (Apr-May)

Blue flowers in winter to spring (Jan-Apr outdoors; spring to summer for pots overwintered indoors). Harvest year-round in mild zones

Trim lightly after flowering. Avoid cutting into old wood

Stem cuttings

Pest

Look for: Stippling, fine webbing, cottony masses

What to do: Hose off, insecticidal soap

Disease

Soilborne root-rot organisms favored by overwatering and poorly drained soil

Look for: Wilting, browning tips, plant death in wet soil

What to do: Improve drainage, avoid overwatering

Disease

Powdery mildew fungus (Sphaerotheca)

Look for: White powdery coating on leaves and stems

What to do: Good air circulation and spacing, remove infected leaves; sulfur or horticultural oil if severe

Always read and follow the label on any treatment, and check it is approved for use where you live.

Pets and people: Non-toxic to dogs, cats and horses (ASPCA, NC State Extension)

Weed risk: None known

Checked against two or more reputable gardening sources. How we check our facts

Growing somewhere else? See this plant for the UK and Australia.

Keep it by the back door

Printable pest and disease charts with real photographs, and all 50 USA plants in one book.