Purple basil

Sun

Full sun, ideally at least 6 hours daily; light afternoon shade can help in very hot climates.

Water

Keep evenly moist but not waterlogged. Water when the soil surface begins to dry; containers may need daily checking in hot weather.

Soil

Fertile, well-drained soil enriched with compost; avoid cold, wet ground.

Height

1-2 ft (0.3-0.6 m)

Spread

1-1.5 ft (0.3-0.45 m)

Flowers

Spikes of small pale pink to lavender flowers in summer and early autumn if shoots are not regularly pinched.

Foliage

Broad, aromatic, dark purple leaves with deeply puckered surfaces and strongly toothed, ruffled edges; some green colouring can occur.

Growth

Fast in warm weather.

Care needed

Medium

• Pollinators
• Heat tolerant
• Low allergen
• Fragrant
• Edible

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Needs looking after

Pick your zone, country, light and whether you have pets.

1. Planting day

   0.5 ft (0.15 m)

2. After 1 year

   1.5 ft (0.45 m)

   full size

Full size in one season.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

Australia

Growth rate

Fast

• Plant out after frost danger has passed and nights are consistently above 10°C (50°F); protect from cold winds.
• Space plants about 1-1.5 ft (0.3-0.45 m) apart so air can move between them.
• Water at soil level, preferably in the morning, without leaving pots standing in water.
• Mix compost into beds before planting; feed container plants lightly with a balanced liquid fertiliser according to its label.
• Apply a thin organic mulch once the soil is warm, keeping it clear of the stems.

Pruning. Once plants have several pairs of leaves, pinch out shoot tips just above a pair of leaves to encourage branching. Harvest this way throughout summer and remove flower spikes promptly if leaf production is the priority.

Start harvesting once plants are 15–20 cm (6–8 in) tall with several pairs of healthy, fully opened leaves, usually in late spring or summer after warm weather arrives. Pick individual leaves or snip shoot tips just above a pair of leaves, taking no more than one-third of the plant at a time.

Early spring

Sow indoors in a bright, warm position, about 6 weeks before your expected last frost.

Late spring

Harden plants off gradually and plant outside once nights are reliably warm.

Early summer

Pinch growing tips to build bushy plants and begin light harvesting.

Summer

Check moisture frequently, harvest regularly and remove flower spikes unless wanted for pollinators.

Late summer

Take cuttings from healthy, non-flowering shoots if you want young plants for a bright indoor position.

Autumn

Harvest remaining usable leaves before cold weather; remove plants killed by frost.

• Edge vegetable beds with purple foliage that contrasts with green lettuces and herbs.
• Use in sunny patio pots with green basil or compact marigolds for contrasting colour and texture.
• Repeat small groups near the front of a summer border among pale flowers.
• Plant in a geometric herb parterre, pinching regularly to keep the outlines compact.

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

Plant it with: Tomatoes, Sweet peppers, Green sweet basil, French marigolds, Dwarf zinnias and Lettuce.

Wildlife: Flowers provide nectar and pollen for bees and other visiting insects. Leave a few plants or shoots unpinched if you want them to flower.

• Slugs and snails can strip young plants: check after dark, remove them by hand and protect new transplants.
• Aphids gather on tender shoots: rinse off small colonies with water and check growing tips regularly.
• Basil downy mildew causes yellowing or pale patches above and grey-purple growth beneath leaves: remove affected plants, improve spacing and avoid wetting foliage.
• Cold or waterlogged soil causes stalled growth, blackened leaves or root rot: delay planting until warm weather and use freely draining soil or containers.

Sweet basil is not known to be toxic to cats, dogs, horses or people. Its leaves and flowers are edible; eating large quantities may cause digestive upset. Concentrated basil essential oil is not equivalent to the fresh plant and should not be given to pets.

• Dark Opal basil (Ocimum basilicum 'Dark Opal')

  Also has purple, basil-scented leaves, but they are much flatter and less deeply fringed than those of Purple Ruffles.

• Purple shiso (Perilla frutescens)

  Can have similarly crinkled purple leaves, but they are generally broader and more sharply saw-toothed, with a distinct shiso aroma rather than sweet basil's scent. Do not identify edible plants by colour alone.

The name basil comes from a Greek word meaning royal, while 'Purple Ruffles' describes the cultivar's purple, heavily ruffled leaves.

Propagation. Sow named seed indoors in warmth, around 20-25°C (68-77°F), covering lightly. Non-flowering stem cuttings root readily in water or moist potting mix. Home-saved seed may not match the parent because basil cultivars can cross-pollinate; remove green off-types if maintaining purple foliage.

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.