Mearns' Bird's-foot Trefoil Plant Care
Acmispon mearnsii (Britton) Brouillet
Updated · Sources · How we source care data
Acmispon mearnsii, synonym Lotus mearnsii, is a species of flowering plant in the legume family endemic to Arizona in the United States. It known by the common name Mearns' bird's-foot trefoil.
Every 7–14 days
Full sun to partial shade
50–85°F
30–60%
At a glance
How do you care for Mearns' Bird's-foot Trefoil?
Plant Mearns' Bird's-foot Trefoil in full sun to partial shade (USDA zones 12a) and water a young shrub every 7–14 days until it is established. It tolerates temperatures of 50–85°F (10–29°C). Fertilize it every 6 months during the growing season.
Where Is the Mearns' Bird's-foot Trefoil Native To?
What Is the Mearns' Bird's-foot Trefoil?
Mearns' Bird's-foot Trefoil (Acmispon mearnsii) belongs to the Fabaceae family within the Acmispon genus. Mearns' Bird's-foot Trefoil is native to Arizona in the United States. Mearns' Bird's-foot Trefoil is also known as Mearns' Lotus.
Mearns' Bird's-foot Trefoil displays a low spreading shrub growth habit, reaching up to 1.5 ft tall with a spread of approximately 3 ft. Mearns' Bird's-foot Trefoil produces small yellow flowers in clusters.
Leaf size: approximately 2 inches.
How Often Should You Water a Mearns' Bird's-foot Trefoil?
Water a young or newly planted Mearns' Bird's-foot Trefoil every 7–14 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established shrubs mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.
Watering Frequency
Every 7–14 days
Until established; then in dry spells
What Light Does the Mearns' Bird's-foot Trefoil Need?
Mearns' Bird's-foot Trefoil thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Mearns' Bird's-foot Trefoil Prefer?
Acmispon mearnsii tolerates temperatures of 50–85°F. Mearns' Bird's-foot Trefoil prefers humidity levels of 30–60%.
Temperature
50–85°F
Humidity
30–60%
What Soil Mix Works Best for a Mearns' Bird's-foot Trefoil?
Well-draining sandy soil with good organic content. Good drainage is essential for Mearns' Bird's-foot Trefoil to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Mearns' Bird's-foot Trefoil?
Feed Mearns' Bird's-foot Trefoil every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established shrubs in good soil often need little extra feeding, so let weak growth or pale foliage guide you.
Stop feeding by late summer so new growth can harden before winter.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
Where Should You Plant a Mearns' Bird's-foot Trefoil?
Choose a spot with full sun to partial shade and well-draining sandy soil with good organic content. Avoid low spots where water collects after rain.
Mearns' Bird's-foot Trefoil is suited to USDA Zone 12a.
Plant container-grown or balled-and-burlapped shrubs in spring or early autumn, setting the root flare at soil level, and water well after planting.
How Far Apart Should You Plant a Mearns' Bird's-foot Trefoil?
Mearns' Bird's-foot Trefoil can spread to about 3 ft (0.9 m) and reach about 2 ft (0 m) tall. Space plants about 3 ft (0.9 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.
Planning a row or hedge? Try the plant spacing calculator.
How Do You Prune a Mearns' Bird's-foot Trefoil?
Prune Mearns' Bird's-foot Trefoil while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.
If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the shrub in one year.
How Do You Care for a Mearns' Bird's-foot Trefoil in Winter?
Mearns' Bird's-foot Trefoil is frost-tender (hardy to USDA zone 12). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.
How Do You Propagate a Mearns' Bird's-foot Trefoil?
Mearns' Bird's-foot Trefoil can be propagated through seeds, division. Similar propagation techniques also apply to american bird's-foot trefoil plant care, which shares the same genus.
Is the Mearns' Bird's-foot Trefoil Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Mearns' Bird's-foot Trefoil, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Mearns' Bird's-foot Trefoil?
Mearns' Bird's-foot Trefoil is susceptible to aphids, whiteflies, spider mites. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Mearns' Bird's-foot Trefoil Need?
Mearns' Bird's-foot Trefoil grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Mearns' Bird's-foot Trefoil is native to Arizona in the United States. In cooler regions, grow Mearns' Bird's-foot Trefoil as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Mearns' Bird's-foot Trefoil is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Acmispon genus — compare its care with other Acmispon species on PlantoScan.
Acmispon is part of the Fabaceae plant family — browse all Fabaceae genera and species.
Mearns' Bird's-foot Trefoil thrives in bright light and direct sun — see other bright-light plants.
More Acmispon Species
Other Acmispon species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Acmispon mearnsii (Britton) Brouillet, family Fabaceae (first published in J. Bot. Res. Inst. Texas 2: 391 (2008)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Mearns' Bird's-foot Trefoil, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
