1 / 7
Overview
A rhizomatous, colony-forming, deciduous herbaceous perennial in the family Asparagaceae, native to coastal temperate rainforests, moist conifer forests, and streamside habitats from Alaska south through British Columbia, Washington, and Oregon to northern California — often the single dominant herbaceous groundcover in Sitka spruce and western hemlock forests. The specific epithet dilatatum means 'spread wide' or 'expanded,' referring to the broadly expanded, heart-shaped leaf bases. Plants grow 4–14 inches (10–35 cm) tall, with each stem bearing 1–3 broadly heart-shaped to arrow-shaped, shiny, dark green leaves 2–4 inches (5–10 cm) long with prominently cordate (heart-shaped) bases and a distinctly pleated, prominently veined surface. From May through June, each stem tip produces a dense, upright, cylindrical raceme 1–3 inches (2.5–8 cm) long of small, white, four-parted (not six-parted) flowers — the four tepals are diagnostic and distinguish this species from the six-parted flowers of Maianthemum racemosum and M. stellatum. Berries ripen from mottled green-white with red spots to solid bright red by late summer and are consumed by thrushes, grouse, and bears. Berries are mildly toxic to humans in quantity. Spreads aggressively by creeping rhizomes and can form extensive, dense colonies in suitable conditions.
Native Range
Native to coastal temperate rainforests, moist conifer forests, and streamside habitats from Alaska south through British Columbia, Washington, and Oregon to northern California.Suggested Uses
Planted as a native woodland groundcover for large-scale or naturalistic Pacific Northwest shade gardens and coastal forest restorations, allowing 18–24 inch (45–60 cm) spacing for spread. Among the most characteristic and ecologically dominant groundcovers of coastal PNW conifer forests. The shiny heart-shaped leaves, white flower racemes, and red berries provide multi-season interest. Combines with Oxalis oregana, Achlys triphylla, Gymnocarpium disjunctum, and Cornus unalaschkensis in cool, moist, acidic conifer forest floor plantings. Best where spreading is permitted.How to Identify
Appearance
Size & Dimensions
Height4" - 1'2"
Width/Spread1' - 3'
Bloom Information
Blooms May through June for 3–4 weeks, producing dense, upright cylindrical racemes of small white four-parted flowers at each stem tip. The four-tepaled flowers (not six) are diagnostic for the species within the genus. Berries begin as mottled green-white with red spots and ripen to solid bright red by August–September, providing food for thrushes, grouse, bears, and other wildlife.Detailed Descriptions
Flower Description
white; small four-parted flowers (4 tepals — diagnostic: distinguishes from M. racemosum and M. stellatum which have 6 tepals); dense upright cylindrical raceme 1–3 inches; May–June; berries mottled green-white to bright red by Aug–SeptFoliage Description
shiny dark green; broadly heart-shaped to arrow-shaped, 2–4 inches with prominently expanded cordate base (dilatatum = 'spread wide') and pleated prominently veined surface; 1–3 per stemGrowing Conditions
Sun Requirements
Tolerates up to 3 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
Plant in partial to full shade in moist to wet, humus-rich, acidic soil with a pH of 4.5–6.5. Replicates naturally in cool, moist, shaded conditions — thrives under western hemlock, Sitka spruce, and red alder in coastal PNW settings. Spreads aggressively by rhizome in suitable conditions and may overtake smaller companions. Can be invasive within cultivated garden beds — best in wilder, naturalistic plantings or as a woodland groundcover where spreading is acceptable. No fertilizer needed.Pruning
No pruning required. Remove dead stems in late winter. Divide spreading colonies with a spade in early spring to manage spread. Rhizomes are vigorous — use a physical barrier if adjacent to formal plantings.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
early spring