Polygala myrtifolia
sweet pea shrub
Overview
Polygala myrtifolia is an evergreen shrub in the milkwort family reaching 3-8 feet (1-2.5 m) tall and 3-6 feet (1-1.8 m) wide, with an upright, rounded, densely branched form. Leaves are oval to oblong, 0.6-1.6 inches (1.5-4 cm) long, grey-green and slightly leathery. The pea-like flowers, 0.6-1 inch (15-25 mm) across, are magenta to purple (occasionally white), each with two wing-like sepals and a keel petal tipped with a fringed brush of threads. Flowering occurs over most of the year, peaking in spring. Flowers are followed by flattened winged capsules holding a few seeds. Growth is fast, and plants reach full size in 2-3 years. The species seeds freely and is naturalised in many warm-temperate regions, where it is classed as an environmental weed.
Native Range
Native to South Africa, in coastal scrub and fynbos of the southern and eastern Cape. Naturalised in parts of Australia, New Zealand, California, and the Mediterranean, where it grows on coastal slopes, bushland, roadsides, and disturbed sites. It is listed as an environmental weed in several Australian states, including Victoria, South Australia, and Western Australia.Suggested Uses
Grown in coastal and low-water gardens, on banks, and as an informal hedge or screen, spaced 3-5 feet (0.9-1.5 m) apart. The long flowering season suits mixed shrub borders in mild climates. Its weed status and heavy self-seeding limit its use near bushland.How to Identify
Appearance
Size & Dimensions
Height3' - 8'
Width/Spread3' - 6'
Reaches mature size in approximately 3 years
Bloom Information
Flowers through most of the year in mild climates, with a strong peak in spring and early summer from September to December. Scattered flowers appear in other seasons. Each flush lasts several weeks, and overlapping flushes give an almost continuous display. Cool or dry conditions slow flowering.
Detailed Descriptions
Flower Description
magenta to purpleFoliage Description
grey-greenGrowing Conditions
Sun Requirements
Requires 5-9 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grows in well-drained sandy or loamy soil in full sun to part shade, tolerating coastal exposure, salt, and dry conditions once established. Water through the first season; mature plants need little extra water. The shrub seeds heavily and self-sown seedlings appear readily, so it can spread into surrounding bushland. Few pests or diseases trouble it. Plants are short-lived, often declining after 6-10 years. Its weed status restricts planting in several regions.Pruning
Prune after the main spring flush to keep a compact shape and remove spent seed capsules, which also limits self-seeding. Plants reshoot well from older wood after moderate cutting. Removing developing capsules reduces unwanted seedlings. Light trimming several times a year maintains density.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
summer
Container Growing
✓ Suitable for container growing
Minimum container size: 5 gallons