How to Grow Sweet Pea Shrub
Polygala myrtifolia
Sweet Pea Shrub thrives in full sun to partial shade in well-drained, moderately fertile soil. It flowers prolifically from spring through autumn with vivid purple-pink blooms. In frost-prone climates, grow in a container and bring under glass before winter. Water freely during summer and feed with a balanced fertiliser each spring. Tip-prune lightly after flowering flushes to keep growth compact and bushy.
In your Leaftide garden 
- Height
- 200 cm
- Spread
- 180 cm
- Flowers
- May - August
- Light
- Full sun to part shade
- Water
- Moderate
- Feed
- Balanced feed in spring
- Prune
- Tip-prune after flowering flushes
Yearly Lifecycle
Care Essentials
Spring, with a balanced all-purpose fertiliser. Avoid excess nitrogen, which promotes leafy growth at the expense of flowers.
Watch For
- Aphids (especially under glass)
- Whitefly (under glass)
- Root rot in waterlogged or poorly drained soil
Companions
Agapanthus, Lavender, Cistus, Osteospermum
Care Requirements
Light
Full sun to partial shade; sheltered from cold winds
Prefers full sun but tolerates morning sun with afternoon shade. Avoid deep shade, which reduces flowering. Always choose a sheltered spot protected from frost and cold winds.
Watering
Moderate; water freely in summer, reduce in winter
Water freely during the growing season, especially in containers. Reduce watering significantly in winter to prevent root rot. The plant is fairly drought-tolerant once established in the ground.
Fertilizing
Balanced feed in spring; avoid excess nitrogen
Apply a balanced all-purpose fertiliser once in spring. Avoid high-nitrogen feeds which promote leafy growth at the expense of the prolific flowering. Container plants benefit from a dilute liquid feed monthly through summer.
Pruning
Tip-prune after flowering flushes; hard prune if leggy
Lightly trim stem tips after each flush of flowers to maintain a bushy, compact habit. Remove frost-damaged shoots in spring. If the plant becomes woody and bare at the base, cut back hard in spring — it regenerates well from old wood.
Spacing
150–200 cm apart
Space plants 150–200 cm apart to allow for mature spread of up to 180 cm. In containers, use a pot at least 40 cm wide. Allow good air circulation around the plant.
Support
None required; free-standing shrub
Polygala myrtifolia is a self-supporting, free-standing shrub that does not require staking or tying in under normal conditions.
Growing Tips
Tip-prune after flowering
Lightly pinch or trim stem tips after each flush of flowers. This keeps the plant bushy rather than leggy and encourages the next wave of blooms.
Protect from frost
This South African shrub is frost-tender. In cool climates, grow in a container so you can move it under glass or indoors before the first frost of autumn.
Sharply drained soil is essential
Polygala myrtifolia dislikes waterlogged conditions. Plant in free-draining soil amended with grit or coarse sand, and avoid overwatering in winter.
Hard rejuvenation pruning
If the plant becomes woody and bare at the base, cut it back hard in spring. It regenerates well from old wood and will flush with new growth.