Acmispon tomentosus var. glabriusculus (Heermann’s Lotus, Heermann’s Bird’s-Foot Trefoil, Prostrate Woolly Lotus) is a low-growing California native perennial in the pea family. It has also been treated in older references and the nursery industry as Acmispon heermannii var. heermannii and Lotus heermannii var. heermannii. Native to California and northwestern Baja California, it occurs in dry washes, riverbanks, chaparral openings, coastal sage scrub, and other well-drained native habitats. This species is grown for its prostrate to spreading habit, fine-textured foliage, yellow to reddish pea-like flowers, and value in dry native plantings where seasonal change and dormancy is acceptable.
Quick Facts:
Botanical Name: Acmispon tomentosus var. glabriusculus
Common Name: Heermann’s Lotus, Heermann’s Bird’s-Foot Trefoil, Prostrate Woolly Lotus
Plant Type: California native perennial herb; seasonal groundcover
Mature Size: Approximately 6–12 inches tall and 1–2 feet wide, depending on site conditions
Exposure: Full sun to part sun
Water: Low once established; occasional irrigation during establishment
Soil: Well-drained sandy, rocky, gravelly, decomposed granite, alluvial, and native soils
Bloom Season: Spring through summer, with flowering sometimes extending later under favorable conditions
Flower Color: Yellow, often aging or marked with red, orange, maroon, or burgundy tones
Foliage Color: Gray-green, often with a soft or hairy texture
Seasonality: Summer-deciduous or summer-dormant under dry conditions
Wildlife Value: Supports native bees, butterflies, moths, and other pollinators
Origin: California and northwestern Baja California
California Native: Yes
Landscape Uses: Native gardens, dry slopes, informal groundcover plantings, habitat gardens, pollinator gardens, coastal sage scrub plantings, chaparral plantings, restoration projects, containers, and low-water landscapes. Not suitable for most large scale commercial applications.
Habit & Size: Heermann’s Lotus forms a low, spreading to prostrate perennial, typically remaining under 1 foot tall and spreading approximately 1–2 feet wide. The foliage is fine textured, green to gray-green, and may have a soft or hairy appearance. Flowers are pea-like and usually yellow with red, orange, maroon, or burgundy tones developing as they age. Flowering is heaviest in spring and can continue into summer or later where moisture and temperature remain favorable. Under dry late-summer conditions, plants may thin, become sparse, or go dormant.
Cultural Requirements: Acmispon tomentosus var. glabriusculus performs best in full sun to part sun with well-drained soil. Occasional irrigation during establishment is appropriate, but mature plants generally perform best with low water particularly in the summer months. In heavier soils or irrigated landscapes, avoid frequent summer watering and prolonged wet conditions. Summer dormancy or seasonal thinning is normal and should not automatically be interpreted as plant failure or the need for more water.
Landscape Uses: Useful as an informal California native groundcover, seasonal filler, slope plant, pollinator plant, or restoration species. It is best suited to naturalistic landscapes, coastal sage scrub-inspired plantings, chaparral gardens, habitat gardens, and other low-water areas where a consistently dense, year-round groundcover is not required. It may also be useful in containers or small specialty native gardens where its flower color and fine texture can be appreciated up close.
Identification Note: Acmispon tomentosus var. glabriusculus is distinguished by its low, spreading to prostrate habit, fine-textured foliage, and yellow pea-like flowers that often show red, orange, maroon, or burgundy tones. It has been widely referenced under the names Acmispon heermannii and Lotus heermannii, so various references may use those names. It should not be confused with Acmispon glaber (Lotus scoparius), commonly known as Deerweed, which is typically a much taller, more upright subshrub.
Pests and Cultural Considerations: Generally low maintenance when grown in well-drained soil with limited irrigation. The most common problems are cultural rather than pest-related, especially excessive irrigation, poor drainage, or expectations that the plant will remain lush through summer.
Frequently Asked Questions: Is Acmispon tomentosus var. glabriusculus native to California? Yes. It is native to California and also occurs in northwestern Baja California.
What is the common name for Acmispon tomentosus var. glabriusculus? Common names include Heermann’s Lotus, Heermann’s Bird’s-Foot Trefoil, and Prostrate Woolly Lotus. Other references may list it as Acmispon heermannii or Lotus heermannii.
Is this the same plant as Acmispon heermannii? In current taxonomy, material commonly known as Acmispon heermannii var. heermannii is treated as Acmispon tomentosus var. glabriusculus. Because the older name is still common in nursery and restoration references, both names may be encountered.
How large does Heermann’s Lotus grow? It is a low-growing perennial, typically about 6–12 inches tall and 1–2 feet wide, depending on site conditions and irrigation.
What color are the flowers? Flowers are pea-like and usually yellow, often aging or marked with red, orange, maroon, or burgundy tones.
When does Heermann’s Lotus bloom? Flowering is typically heaviest from spring into summer, with bloom sometimes extending later where conditions remain favorable.
Is Heermann’s Lotus evergreen? No. It is best treated as a seasonal perennial that may become summer-deciduous or summer-dormant under dry conditions.
Is Acmispon tomentosus var. glabriusculus drought tolerant? Yes. Once established, it is drought tolerant and adapted to low-water native landscapes.
Does Heermann’s Lotus attract pollinators? Yes. The flowers support native bees, butterflies, moths, and other pollinators.
How should this plant be used in the landscape? Use it in native gardens, dry slopes, informal groundcover plantings, restoration projects, coastal sage scrub plantings, chaparral gardens, habitat gardens, containers, and low-water landscapes where seasonal dormancy is acceptable. Particularly interesting in California native only gardens that have room for a more unique item that surely will be discussed.
Is Heermann’s Lotus a good formal groundcover? No. It is better used as an informal, seasonal native groundcover or restoration plant rather than as a formal evergreen groundcover expected to remain dense year-round.
What problems should be avoided? Avoid heavy irrigation, poorly drained soils, overly rich conditions, and expectations of year-round lush growth. It should be planted around other plants that will provide interest during its dormant period.
