How to grow morning glory
Overview
Morning glory (Ipomoea purpurea) is a fast-growing annual vine native to tropical America, prized for its rapid coverage of trellises, fences, and arbors with heart-shaped leaves and trumpet-shaped flowers. It thrives in full sun and warm weather, and will self-seed readily in Australian gardens, making it both a delightful and potentially invasive climber.
Varieties
- Heavenly Blue — Classic variety with large, sky-blue flowers; vigorous and reliable in Australian gardens.
- Grandpa Ott's — A heritage variety with deep purple flowers and a pronounced red star in the centre.
- Crimson Rambler — Produces rich red flowers with a white throat; excellent for warm climates.
- Pearl Gates — White flowers with soft pink centres; creates a cool, elegant display.
Soil Preparation
Morning glory grows best in well-drained, moderately fertile soil with a pH of 6.0–7.0. Dig in some compost before planting, but avoid excessive organic matter as it can delay flowering. Tolerates poorer soils but growth will be reduced.
Growing Guide
Direct sow seeds after the last frost in spring, soaking them overnight to improve germination. Sow 1 cm deep and space 30 cm apart, providing a sturdy trellis or support from the start. Pinch out the growing tips when the vine is 30 cm tall to encourage branching and more flowers. Keep the soil consistently moist but not waterlogged, and avoid high-nitrogen fertilisers which promote lush foliage at the expense of blooms.
Sowing
Sow seeds directly in the garden after the last frost, 1 cm deep and spaced 30 cm apart. Nicking the seed coat or soaking in warm water for 24 hours greatly improves germination, which takes 5–14 days. You can also start seeds in pots for earlier blooms, but transplant carefully to avoid root disturbance.
Care
Feed monthly with a balanced liquid fertiliser during the active growing season. Train young stems onto their support regularly and pinch out tips to promote bushiness. Remove spent flowers if you want to limit self-seeding and keep the plant tidy.
Companion Planting
Morning glory pairs well with other quick-growing annual climbers like sweet peas (Lathyrus) and nasturtiums (Tropaeolum) for a colourful summer screen. Avoid planting it near valuable food crops, as its self-seeding habit can become weedy, and it can compete aggressively for space and nutrients.
Common Pests & Risks
Aphids and spider mites are common on morning glory, especially in dry weather. Control them with a strong jet of water or insecticidal soap. Powdery mildew can appear in humid, still conditions; improve air circulation and avoid overhead watering to prevent it.
Troubleshooting
Yellow leaves: often overwatering or poor drainage; let soil dry out before watering again. No flowers: too much shade or high nitrogen; move to full sun and switch to a low-nitrogen fertiliser. Powdery mildew: white fungal coating on leaves in humid, crowded conditions; thin foliage and apply a sulfur-based fungicide. Stunted growth: cold soil or poor nutrition; wait for warm weather and enrich soil with compost. Self-seeding: unwanted seedlings can be easily pulled; remove spent flowers before seeds drop.