Lythrum hyssopifolia
hyssop loosestrife
Europe, western Asia, and North Africa (naturalized in Australia)
Overview
Lythrum hyssopifolia is a slender annual to short-lived perennial herb growing 4-24 inches (10-60 cm) tall, with erect, four-angled stems that branch from the base and may be green or red-tinged. The leaves are narrow, oblong to linear, 0.4-1.2 inches (1-3 cm) long, stalkless, and arranged alternately or in opposite pairs along the stem. Small pink to pale purple flowers, each about 0.2 inch (5 mm) across with five to six petals, sit singly in the leaf axils along the upper stem from late spring through autumn. The fruit is a small cylindrical capsule enclosed in the persistent flower tube, releasing numerous tiny seeds. Plants grow quickly in seasonally wet ground and complete flowering and seeding within a single season in many sites. It spreads readily by seed and colonizes damp, disturbed, and bare ground. In some regions it has been linked to a photosensitivity disorder in grazing sheep that eat large amounts of the plant.
Native Range
Native to Europe, western Asia, and North Africa, and widely naturalized in Australia, New Zealand, and North America. Grows in damp, seasonally flooded ground such as ditches, dam edges, wetland margins, and disturbed sites in a range of soils.Suggested Uses
Rarely grown by choice; it appears mainly as a volunteer in wetlands, channel banks, and damp pasture. It has occasional use in wetland and damp-ground revegetation within its native range. In Australia and North America it is regarded as a naturalized weed rather than a garden plant.How to Identify
Appearance
Size & Dimensions
Height4" - 2'
Width/Spread3" - 10"
Bloom Information
Flowers from November to May in Australia, mainly through summer and autumn, with timing tied to soil moisture. Individual flowers are small and short-lived, but plants flower over many weeks as stems extend. Flowering and seeding overlap, so a single plant carries flowers and ripe capsules at the same time.
Detailed Descriptions
Flower Description
pink to pale purpleFoliage Description
green, sometimes red-tingedGrowing Conditions
Sun Requirements
Requires 6-10 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