Basil

Sun

Full sun; light afternoon shade is helpful in very hot climates.

Water

Keep the root zone evenly moist but not waterlogged. Containers may need daily watering in hot weather.

Soil

Fertile, well-drained soil enriched with compost; use free-draining potting mix in containers.

Height

1-3 ft (0.3-0.9 m)

Spread

1-2 ft (0.3-0.6 m)

Flowers

Summer to autumn; small white or pale pink flowers in upright spikes if shoots are not regularly harvested.

Foliage

Soft, aromatic, oval leaves, usually bright green; purple-leaved and small-leaved forms are also grown.

Growth

Fast in warm weather.

Care needed

Medium

• Plant outside after frost risk has passed and nights stay above about 10°C (50°F); growth is better in warmer conditions.
• Water at soil level when the surface begins to dry, avoiding persistently wet roots.
• Mix compost into beds before planting; feed containers lightly with a balanced liquid fertiliser every four weeks during active growth.
• Apply a thin mulch once the soil is warm, keeping it clear of the stems.
• Space plants to allow air movement and protect them from cold winds.

Pruning. Once plants have several pairs of true leaves, pinch out the growing tips just above a leaf pair to encourage branching. Harvest shoots regularly and remove developing flower spikes to maintain leafy growth, leaving some flowers if you want seed or food for insects.

Early spring

Sow indoors in warmth, ideally around 20-25°C (68-77°F), in bright light.

Late spring

Harden plants off gradually and plant outside only after frost risk has passed and nights are reliably warm.

Early summer

Pinch growing tips and begin harvesting small amounts once plants are established.

Summer

Water consistently, feed container plants lightly and remove flower buds for continued leaf production.

Late summer

Sow a replacement batch if enough warm weather remains, or root healthy shoot cuttings for a bright indoor position.

Autumn

Harvest before cold nights damage the leaves; freeze surplus leaves or pesto and remove plants killed by frost.

• Plant beside paths in a kitchen garden so leaves are easy to pick and their scent is released when brushed.
• Use repeated groups along vegetable-bed edges for a leafy, informal border.
• Grow in containers near an outdoor kitchen, paired with parsley or chives in separate pots with similar watering needs.
• Use purple-leaved forms as foliage accents among green herbs and compact flowers.

Garden styles it suits: Potager (kitchen garden), Herb parterre, Edible landscape, Sensory garden, Cottage garden and Small-space.

Plant it with: Tomatoes, Peppers, Parsley, Chives, French marigolds and Lettuce.

Wildlife: Flowers provide nectar and pollen for bees and other visiting insects. Leave a few plants to flower while harvesting the rest.

• Basil downy mildew causes yellow patches between leaf veins and grey-purple growth beneath leaves. Remove affected plants, keep foliage dry and choose resistant varieties for future crops.
• Slugs and snails chew young leaves and can destroy seedlings. Check plants after dark, remove pests and use locally approved iron-phosphate bait if needed.
• Aphids cluster on soft shoots. Wash them off with water; use insecticidal soap labelled for edible herbs if infestations persist.
• Cold or waterlogged conditions cause blackened leaves, poor growth and root decay. Delay planting until nights are warm and improve drainage rather than watering more.

Basil leaves, stems and flowers are not known to be toxic to people, cats, dogs or horses. Large amounts may cause digestive upset. Concentrated essential oil is not equivalent to the culinary herb and should not be given to pets.

• Holy basil (Ocimum tenuiflorum)

  Usually has hairier stems and leaves, more noticeably toothed leaf edges and a stronger clove-like scent; sweet basil generally has smoother, broader leaves.

• Perilla (Perilla frutescens)

  Has broadly oval, often puckered leaves with coarse, sharply toothed edges; basil leaves usually have much smoother margins.

The name basil and the botanical epithet basilicum derive from the Greek basilikos, meaning royal.

Propagation. Sow seed shallowly in warm conditions, covering only lightly. Non-flowering shoot tips also root readily in water or moist propagation mix. In frost-free climates plants may persist, but overwintering is unreliable in cool or wet conditions.

Accepted botanical name

Ocimum basilicum

In the US and Canada

Introduced in Hawaii, the lower 48 states and Puerto Rico.

Native range

Andaman Is., Assam, Bangladesh, Bismarck Archipelago, Borneo, Cambodia, China South-Central, China Southeast, East Himalaya, India, Jawa and Laos.

Measured

Soil pH 6.5 to 7. Average height 36 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.