Broadseed Rock Cress Plant Care

Boechera platysperma (A.Gray) Al-Shehbaz

Updated · Sources · How we source care data

Boechera platysperma, the pioneer rockcress or broad-seeded rock-cress, is a perennial plant in the family Brassicaceae found in western United States mountains.

🌱Herbs
Water

Every 7–10 days

Light

Full sun to partial shade

Temp

50–75°F

Humidity

40–60%

At a glance

How do you care for Broadseed Rock Cress?

Plant Broadseed Rock Cress in full sun to partial shade (USDA zones 12a) and water a young shrub every 7–10 days until it is established. It tolerates temperatures of 50–75°F (10–24°C). Fertilize it every 6 months during the growing season.

Where Is the Broadseed Rock Cress Native To?

Native range1 country

What Is the Broadseed Rock Cress?

Broadseed Rock Cress (Boechera platysperma) belongs to the Brassicaceae family within the Boechera genus. Broadseed Rock Cress is native to western United States mountains. Broadseed Rock Cress is also known as Wide-seeded Rock Cress.

Broadseed Rock Cress displays a low rosette, clumping growth habit, reaching up to 0.5 ft tall with a spread of approximately 0.5 ft. Broadseed Rock Cress produces small white or purple flowers in clusters.

Leaf size: approximately 2 inches.

How Often Should You Water a Broadseed Rock Cress?

Water a young or newly planted Broadseed Rock Cress 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 Broadseed Rock Cress Need?

Broadseed Rock Cress thrives in full sun to partial shade.

Light Requirement

Full sun to partial shade

What Temperature and Humidity Does the Broadseed Rock Cress Prefer?

Boechera platysperma tolerates temperatures of 50–75°F. Broadseed Rock Cress prefers humidity levels of 40–60%.

Temperature

50–75°F

Humidity

40–60%

What Soil Mix Works Best for a Broadseed Rock Cress?

Well-draining sandy loam with added organic matter. Good drainage is essential for Broadseed Rock Cress to prevent waterlogging, which leads to root rot and fungal issues.

How Often Should You Fertilize a Broadseed Rock Cress?

Feed Broadseed Rock Cress 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 Broadseed Rock Cress?

Choose a spot with full sun to partial shade and well-draining sandy loam with added organic matter. Avoid low spots where water collects after rain.

Broadseed Rock Cress 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 Broadseed Rock Cress?

Broadseed Rock Cress can spread to about 1 ft (0.2 m) and reach about 1 ft (0 m) tall. Space plants about 1 ft (0.2 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 Broadseed Rock Cress?

Prune Broadseed Rock Cress 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 Broadseed Rock Cress in Winter?

Broadseed Rock Cress 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 Broadseed Rock Cress?

Broadseed Rock Cress can be propagated through seeds, division of clumps. Similar propagation techniques also apply to boechera breweri plant care, which shares the same genus.

Is the Broadseed Rock Cress Toxic to Pets and Children?

Pet safety not verified

The ASPCA does not list Broadseed Rock Cress, 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 Broadseed Rock Cress?

Broadseed Rock Cress is susceptible to aphids, cabbage worms, flea beetles. 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 Broadseed Rock Cress Need?

Broadseed Rock Cress grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Broadseed Rock Cress is native to western United States mountains. In cooler regions, grow Broadseed Rock Cress as a houseplant or bring it indoors before the first frost.

Hardiness Zone

Zone 12a

Keep exploring plants

Broadseed Rock Cress 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 Boechera genus — compare its care with other Boechera species on PlantoScan.

Boechera is part of the Brassicaceae plant family — browse all Brassicaceae genera and species.

Broadseed Rock Cress thrives in bright light and direct sun — see other bright-light plants.

More Boechera Species

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

Sources

  • Scientific name & taxonomy: Boechera platysperma (A.Gray) Al-Shehbaz, family Brassicaceae (first published in Novon 13: 388 (2003)) — World Flora Online record, IPNI name record.
  • Pet toxicity: Pet safety not verified: the ASPCA does not list Broadseed Rock Cress, 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.

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