Orophaca proimantha (Astragalus proimanthus)

Photo: Charmaine Delmatier / Bureau of Land ManagementPublic domainvia Wikimedia Commons

Orophaca proimantha Plant Care

Astragalus proimanthus Barneby

Updated · Sources · How we source care data

Astragalus proimanthus is a species of flowering plant in the legume family known by the common name precocious milkvetch. It is a narrow endemic, occurring in an area of less than 320 acres near the town of McKinnon in southwestern Sweetwater County, Wyoming. It has four known populations, including one large population of more than 20,000 individuals, and is classified by NatureServe as G1 (critically imperiled) "because of extreme rarity".

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Water

Every 7–10 days

Light

Full sun to partial shade

Temp

60–80°F

Humidity

40–60%

At a glance

How do you care for Orophaca proimantha?

Plant Orophaca proimantha in full sun to partial shade (USDA zones 13a) and water a young shrub every 7–10 days until it is established. It tolerates temperatures of 60–80°F (16–27°C). Fertilize it every 8 months during the growing season.

What Is the Orophaca proimantha?

Orophaca proimantha (Astragalus proimanthus) belongs to the Fabaceae family within the Astragalus genus.

Orophaca proimantha displays a low spreading ground cover growth habit, reaching up to 0.5 ft tall with a spread of approximately 2 ft. Orophaca proimantha produces small pea-like flowers in shades of purple, pink, or white.

Leaf size: approximately 1 inches.

How Often Should You Water a Orophaca proimantha?

Water a young or newly planted Orophaca proimantha every 7–10 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 7–10 days

Until established; then in dry spells

What Light Does the Orophaca proimantha Need?

Orophaca proimantha thrives in full sun to partial shade.

Light Requirement

Full sun to partial shade

What Temperature and Humidity Does the Orophaca proimantha Prefer?

Astragalus proimanthus tolerates temperatures of 60–80°F. Orophaca proimantha prefers humidity levels of 40–60%.

Temperature

60–80°F

Humidity

40–60%

What Soil Mix Works Best for a Orophaca proimantha?

Well-draining sandy soil mix with added perlite for extra drainage. Good drainage is essential for Orophaca proimantha to prevent waterlogging, which leads to root rot and fungal issues.

How Often Should You Fertilize a Orophaca proimantha?

Feed Orophaca proimantha every 8 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 8 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 Orophaca proimantha?

Choose a spot with full sun to partial shade and well-draining sandy soil mix with added perlite for extra drainage. Avoid low spots where water collects after rain.

Orophaca proimantha is suited to USDA Zone 13a.

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 Orophaca proimantha?

Orophaca proimantha can spread to about 2 ft (0.6 m) and reach about 1 ft (0 m) tall. Space plants about 2 ft (0.6 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 Orophaca proimantha?

Prune Orophaca proimantha 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 Orophaca proimantha in Winter?

Orophaca proimantha is frost-tender (hardy to USDA zone 13). 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 Orophaca proimantha?

Orophaca proimantha can be propagated through seeds, division of root ball. Similar propagation techniques also apply to aragallus acutirostris plant care, which shares the same genus.

Is the Orophaca proimantha Toxic to Pets and Children?

Pet safety not verified

The ASPCA does not list Orophaca proimantha, 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 Orophaca proimantha?

Orophaca proimantha is susceptible to aphids, spider mites, leafhoppers. 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 Orophaca proimantha Need?

Orophaca proimantha grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. In cooler regions, grow Orophaca proimantha as a houseplant or bring it indoors before the first frost.

Hardiness Zone

Zone 13a

Keep exploring plants

Orophaca proimantha 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 Astragalus genus — compare its care with other Astragalus species on PlantoScan.

Astragalus is part of the Fabaceae plant family — browse all Fabaceae genera and species.

Orophaca proimantha thrives in bright light and direct sun — see other bright-light plants.

More Astragalus Species

Other Astragalus species in PlantoScan's care catalogue share similar watering, light, and soil preferences:

Sources

  • Scientific name & taxonomy: Astragalus proimanthus Barneby, family Fabaceae (first published in Mem. New York Bot. Gard. 13(2): 1154 (1964)) — World Flora Online record, IPNI name record.
  • Pet toxicity: Pet safety not verified: the ASPCA does not list Orophaca proimantha, 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.
  • Photo: Charmaine Delmatier / Bureau of Land Management, Public domain, Wikimedia Commons — original.
  • Hardiness zone: USDA Zone 13a, 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.

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