How to grow coleus
Overview
Coleus (Plectranthus scutellarioides) is a herbaceous perennial grown for its vividly coloured and patterned foliage. It thrives in part-shade positions and is often used as a seasonal filler in garden beds or containers. The key to success is consistent moisture and regular pinching to keep plants compact and leafy.
Varieties
- Wizard Series — Compact, heat-tolerant mix with many colour combinations; ideal for Australian gardens.
- Kong Series — Very large leaves, excellent for shade; needs consistent moisture to avoid leaf burn.
- Black Prince — Deep burgundy-black foliage; a standout in contrast plantings.
Soil Preparation
Coleus prefers a rich, well-draining soil with a pH between 6.0 and 7.0. Before planting, work in 2–3 cm of compost or well-rotted manure. If using a pot, choose a premium potting mix with added perlite for drainage.
Growing Guide
Plant coleus in a position with morning sun and afternoon shade, or bright filtered light all day. Use a well-draining potting mix or garden soil enriched with compost. Space plants 30–40 cm apart for a full display. Pinch out the growing tips every few weeks until late summer to encourage branching and prevent legginess. Remove any flower spikes as they appear to keep the plant focused on leaf production.
Sowing
Sow coleus seeds 3–5 mm deep in a seed-raising mix, keeping them warm (20–25°C) and moist. Germination takes 10–14 days. Transplant seedlings when they have 2–3 true leaves, spacing them 30–40 cm apart. Direct sowing is possible in warm soil after frost risk has passed.
Care
Feed coleus every two weeks during active growth with a balanced liquid fertiliser (e.g., 10-10-10). In late summer, cut back leggy stems by one-third to refresh the plant. Remove any faded or damaged leaves to keep the display tidy.
Companion Planting
Coleus pairs well with shade-loving begonias, impatiens, and ferns. Avoid planting near heavy feeders like tomatoes that may compete for moisture. In containers, combine with trailing lobelia or ivy for a cascading effect.
Common Pests & Risks
Watch for mealybugs and aphids on new growth and leaf undersides. Treat with a soft spray of water or insecticidal soap. Spider mites can appear in dry conditions; increase humidity by misting. Slugs and snails may damage young leaves; use iron-based pellets or hand pick at dusk.
Troubleshooting
Leggy growth: caused by insufficient light or not pinching tips. Move to brighter spot and pinch regularly. Leaf drop: often from overwatering or cold draughts. Let soil dry slightly and protect from wind. Faded colour: too much direct sun. Shift to more shade. Yellow lower leaves: natural ageing or nitrogen deficiency. Feed with liquid fertiliser.