Heliotropium, Genus, anomalum, Species,
- Genus & species
Hinahina
Hawaiian Islands and tropical Pacific coasts
Overview
Heliotropium anomalum is a low, mat-forming evergreen perennial in the Boraginaceae, 4-12 inches (10-30 cm) tall and spreading 24-48 inches (60-120 cm) across from a woody base. Stems radiate outward along the ground and turn upward at the tips. Leaves are linear to spoon-shaped, 0.5-1.5 inches (1.5-4 cm) long and 0.1-0.3 inch (3-8 mm) wide, crowded into rosette-like clusters at the branch ends, and covered on both surfaces with dense silky hairs that give a silver-gray colour. Flowers are white with a yellow throat, 0.2-0.3 inch (5-8 mm) across, five-lobed, and carried in coiled clusters that unroll as the flowers open; they carry a light scent. Fruit is a dry drupe about 0.1 inch (3 mm) across that splits into corky nutlets buoyant in seawater. A taproot reaches 24-36 inches (60-90 cm) into sand within the first two years. Plants withstand salt spray and wind-blown sand directly on the shoreline. Lifespan runs 3-5 years, and plants rot at the crown within one season in soil that holds moisture or in shade under 6 hours of direct sun.
Native Range
Native to the Hawaiian Islands, growing on coastal sand dunes, beach strand, and coral rubble from sea level to about 100 feet (30 m). It is recorded from Kauai, Niihau, Oahu, Molokai, Lanai, Maui, Kahoolawe, and the Northwestern Hawaiian Islands. The wider species range covers atolls and coastal strand across the tropical Pacific.Suggested Uses
Planted on coastal dunes, sand berms, and beachfront banks at 18-24 inch (45-60 cm) spacing, where the spreading stems hold loose sand within one season. Used in dryland and coastal restoration on Hawaiian shorelines, and grown in containers of 3 gallons (11 L) or larger in a sand-based mix. The silvery foliage is gathered for lei, and the plant is the island emblem of Kahoolawe.How to Identify
Appearance
Size & Dimensions
Height4" - 1'
Width/Spread2' - 4'
Bloom Information
Flowering runs from February through October on Hawaiian coasts, with scattered flowers in other months where winter temperatures stay above 65 degrees F (18 degrees C). Coiled clusters open from the base outward, and a single cluster releases flowers across 3-4 weeks. Individual flowers last 1-2 days. Flowering slows for 4-6 weeks after storm surge buries plants in fresh sand.
Detailed Descriptions
Flower Description
white with a yellow throatFoliage Description
silvery gray-greenGrowing Conditions
Sun Requirements
Requires 8-12 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
Plants grow from seed, which germinates in 2-6 weeks, or from 3-4 inch (8-10 cm) tip cuttings that root in coarse sand within 3-5 weeks. Water twice weekly for the first 8-12 weeks, then stop; established plants live on 8-15 inches (200-380 mm) of annual rainfall and decline under regular irrigation. Soil must drain sharply, with coral sand, beach sand, and cinder all carrying the species at pH 7.0 to 8.5. Overhead watering and enclosed positions bring on stem rot and grey mould within a single wet season. Eight or more hours of direct sun holds the growth compact; under 6 hours the stems lengthen and the silver colour fades toward green. Plants are replaced every 3-5 years as the woody base opens out.Pruning
Stems are trimmed back by 2-4 inches (5-10 cm) in late winter to hold the mat dense, cutting only where leaves remain on the stem. Cuts into bare woody centres regrow slowly and often not at all. Stems buried by drifting sand root at the nodes and are lifted and separated as new plants. Dead stems at the centre are cut out annually as the plant ages.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
early spring
Container Growing
Suitable for container growing
Minimum container size: 3 gallons
