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Philydrum spp.
Frogsmouth
Australia, New Guinea, Southeast Asia, and temperate East Asia
Overview
Philydrum is a genus in the family Philydraceae, represented by the emergent aquatic herb Philydrum lanuginosum, which ranges across freshwater wetlands of Australia, New Guinea, Southeast Asia, southern China, Korea, and Japan. Plants form erect clumps 12-60 inches (30-150 cm) tall, growing from a short rhizome rooted in saturated mud or shallow standing water. The leaves are arranged in two ranks, flattened in one plane like those of an iris, linear to sword-shaped, and 8-24 inches (20-60 cm) long. A single unbranched flowering stem rises above the foliage, clothed in dense woolly white hairs, and carries small yellow flowers arranged spirally along its upper portion. Each flower has two larger and two smaller perianth segments and a single stamen. Flowering occurs mainly in the warmer months, after which dry capsules release numerous small seeds. Philydrum grows in seasonally flooded swamps, pond margins, ditches, and rice-field edges, tolerating conditions from waterlogged soil to about 12 inches (30 cm) of standing water. It withstands seasonal drying once established but does not tolerate hard frost, which kills exposed top growth. In cultivation it is limited to pond margins and bog gardens in frost-free to lightly frosted climates, and it is not suited to dry borders.
Native Range
Philydrum lanuginosum, the sole widely recognized species, occurs from Australia and New Guinea through Southeast Asia to southern China, Korea, and Japan. It grows in lowland freshwater wetlands, swamp margins, and seasonally flooded ground.Suggested Uses
Used in pond margins, bog gardens, and rain-garden basins where soil stays wet. Also grown in containers standing in water as a vertical accent among other marginal aquatics.How to Identify
Appearance
Size & Dimensions
Height1' - 5'
Width/Spread8" - 2'
Bloom Information
Flowering occurs chiefly in spring and summer, with yellow flowers opening in succession up the woolly spike over several weeks. In tropical parts of the range scattered flowering can continue through much of the year. Dry, three-valved capsules follow and split to release numerous small seeds.
Detailed Descriptions
Foliage Description
GreenGrowing 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
Care & Maintenance
Care Guide
Grow in full sun to light shade in a permanently moist to flooded position, such as a pond margin, bog bed, or container standing in a saucer of water. Philydrum accepts most soil textures provided the root zone stays saturated, and it spreads slowly by short rhizomes to form clumps. Water needs are constant, and the root zone should not dry out during active growth. It grows in warm conditions and stops growing below about 50F (10C), with frost killing exposed foliage. In climates with hard freezes, plants are overwintered as rhizomes in frost-free water or moved under cover as container subjects. Routine feeding is minimal, and an annual top-up of aquatic compost in spring maintains steady growth.Pruning
Remove spent flowering stems and frost-damaged or yellowing leaves at the base to keep clumps open. Cut back old foliage in late winter before new growth emerges. No structural pruning is required.Container Growing
Suitable for container growing
Minimum container size: 3 gallons