How to grow impatiens
Overview
Impatiens walleriana is a tender herbaceous perennial grown as an annual for its abundant, colourful flowers and glossy foliage. It thrives in moist, shaded conditions and is ideal for filling gaps in garden beds or containers.
Varieties
- Impatiens walleriana 'Accent' — Compact, early-flowering series with a wide colour range, ideal for Australian garden beds.
- Impatiens walleriana 'Super Elfin' — Spreading habit, excellent for hanging baskets and shade borders; very heat tolerant.
- Impatiens walleriana 'Fiesta' — Double flowers in pink, red, and white; good for containers and moist shade.
Soil Preparation
Impatiens prefers slightly acidic soil (pH 6.0–6.5) rich in organic matter. Before planting, work in compost or well-rotted manure to improve moisture retention and drainage. Avoid heavy clay soils that stay waterlogged; add sand or perlite if needed.
Growing Guide
Plant impatiens in a bright, sheltered spot with dappled shade, avoiding deep dry shade or direct afternoon sun. Space plants 20–30 cm apart in well-draining, moisture-retentive soil enriched with organic matter. Water regularly to keep the root zone consistently moist but not waterlogged. In cooler zones, wait until after the last frost to plant out; in subtropical areas, plant in autumn for a winter–spring display. Pinch out early growing tips to encourage bushiness and delay flowering until the plant is well established.
Sowing
Sow seeds on the surface of a fine seed mix, barely covering, as they need light to germinate. Keep at 21–24°C and moist; seedlings emerge in 10–14 days. Transplant when 5–8 cm tall. Direct sowing is not recommended in most climates.
Care
Feed monthly with a balanced liquid fertiliser (e.g., 10-10-10) during active growth. Pinch back leggy stems to maintain a compact shape and remove spent flowers regularly to extend the blooming period. Cut back hard in late summer if plants become straggly.
Companion Planting
Good companions include begonias, coleus, ferns, and hostas, which share similar shade and moisture requirements. Avoid planting near heavy feeders like tomatoes or in dry, sunny spots where impatiens will struggle.
Common Pests & Risks
Downy mildew is the most serious disease, causing leaf yellowing and collapse; improve air circulation and avoid overhead watering. Aphids and slugs can be controlled with insecticidal soap or organic pellets. Remove affected foliage promptly to prevent spread.
Troubleshooting
Yellow leaves: overwatering or poor drainage; let soil dry slightly. Brown leaf edges: low humidity or sun scorch; move to shadier spot. Leggy growth: insufficient light; pinch back and relocate. Flower drop: heat stress or drought; maintain steady moisture. Downy mildew: white fuzz on leaf undersides; remove affected plants and improve air flow.