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© Donald Hobern from Canberra, Australia, some rights reserved (CC-BY) · Wikimedia Commons
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Hypericum gramineum
small St John's wort
Australia, New Zealand, and the Pacific
Overview
Hypericum gramineum, the small St John's wort, is a slender native perennial herb in the family Hypericaceae found in Australia, New Zealand, and nearby Pacific regions. Wiry, upright stems 4-16 inches (10-40 cm) tall carry pairs of small, narrow, stalkless leaves 0.2-0.6 inch (5-15 mm) long, marked with tiny translucent gland dots that show when held to light. From spring into summer the stems bear small, five-petalled yellow flowers about 0.3-0.5 inch (8-12 mm) across, opening a few at a time and followed by small reddish capsules. The plant grows in grassland, open woodland, and damp depressions on loam, sand, and clay soils, often among other low herbs. It is a short-lived perennial that also behaves as an annual on disturbed ground and self-seeds freely. Like other Hypericum spp., the foliage contains hypericin, a compound that can cause photosensitisation in grazing animals that eat large amounts. Its small size and open habit make it easy to overlook except when flowering.
Native Range
Hypericum gramineum is native to Australia, New Zealand, New Caledonia, and parts of South-East Asia. In Australia it occurs in all states, growing in native grassland, grassy woodland, and seasonally damp ground on a range of soils.Suggested Uses
Grown in native grassland plantings, meadow mixes, and damp rockeries, and in revegetation of grassy ground. Suited to informal, sunny, seasonally moist sites among other low herbs. Spaced 6-10 inches (15-25 cm) apart in drifts.How to Identify
Appearance
Size & Dimensions
Height4" - 1'4"
Width/Spread4" - 8"
Bloom Information
Detailed Descriptions
Foliage Description
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 full sun to light shade on loam, sand, or clay soils that stay moist through the growing season. Even moisture supports steady growth and flowering, while prolonged drought cuts it back early. The plant is short-lived but renews itself by self-seeding on open ground, so it persists as a colony rather than as long-lived individuals. Light feeding in spring supports flowering. It needs open, uncrowded ground, as dense competition shades it out. Cutting back after seeding tidies the clump and limits unwanted spread.Pruning
Trimming spent stems after flowering keeps the clump tidy and reduces self-seeding where it is not wanted. No structural pruning is needed. Old stems can be cut to the base as the plant dies down.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
summer
Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons