Milkwort Jewelflower Plant Care

Streptanthus polygaloides A.Gray

Updated · Sources · How we source care data

Streptanthus polygaloides is a species of flowering plant in the mustard family known by the common name milkwort jewelflower. It is endemic to serpentine soils of the Sierra Nevada foothills of California, where it found in chaparral, grassland, and clearings in oak woodland.

🌱Herbs
Water

Every 7–10 days

Light

Full sun to partial shade

Temp

50–80°F

Humidity

40–60%

At a glance

How do you care for Milkwort Jewelflower?

Plant Milkwort Jewelflower 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 50–80°F (10–27°C). Fertilize it every 6 months during the growing season.

What Is the Milkwort Jewelflower?

Milkwort Jewelflower (Streptanthus polygaloides) belongs to the Brassicaceae family within the Streptanthus genus. Milkwort Jewelflower is native to chaparral, grassland, and clearings in oak woodland.

Milkwort Jewelflower displays an upright, branching growth habit, reaching up to 1.5 ft tall with a spread of approximately 1 ft. Milkwort Jewelflower produces small, tubular flowers in shades of purple, pink, or white.

Leaf size: approximately 3 inches.

How Often Should You Water a Milkwort Jewelflower?

Water a young or newly planted Milkwort Jewelflower 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 Milkwort Jewelflower Need?

Milkwort Jewelflower thrives in full sun to partial shade.

Light Requirement

Full sun to partial shade

What Temperature and Humidity Does the Milkwort Jewelflower Prefer?

Streptanthus polygaloides tolerates temperatures of 50–80°F. Milkwort Jewelflower prefers humidity levels of 40–60%.

Temperature

50–80°F

Humidity

40–60%

What Soil Mix Works Best for a Milkwort Jewelflower?

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

How Often Should You Fertilize a Milkwort Jewelflower?

Feed Milkwort Jewelflower 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 Milkwort Jewelflower?

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.

Milkwort Jewelflower 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 Milkwort Jewelflower?

Milkwort Jewelflower can spread to about 1 ft (0.3 m) and reach about 2 ft (0 m) tall. Space plants about 1 ft (0.3 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 Milkwort Jewelflower?

Prune Milkwort Jewelflower 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 Milkwort Jewelflower in Winter?

Milkwort Jewelflower 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 Milkwort Jewelflower?

Milkwort Jewelflower can be propagated through seeds. Similar propagation techniques also apply to streptanthus anceps plant care, which shares the same genus.

Is the Milkwort Jewelflower Toxic to Pets and Children?

Pet safety not verified

The ASPCA does not list Milkwort Jewelflower, 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 Milkwort Jewelflower?

Milkwort Jewelflower 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 Milkwort Jewelflower Need?

Milkwort Jewelflower grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Milkwort Jewelflower is native to chaparral, grassland, and clearings in oak woodland. In cooler regions, grow Milkwort Jewelflower as a houseplant or bring it indoors before the first frost.

Hardiness Zone

Zone 12a

Keep exploring plants

Milkwort Jewelflower 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 Streptanthus genus — compare its care with other Streptanthus species on PlantoScan.

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

Milkwort Jewelflower thrives in bright light and direct sun — see other bright-light plants.

More Streptanthus Species

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

Sources

  • Scientific name & taxonomy: Streptanthus polygaloides A.Gray, family Brassicaceae (first published in Proc. Amer. Acad. Arts 1: 519 (1865)) — World Flora Online record, IPNI name record.
  • Pet toxicity: Pet safety not verified: the ASPCA does not list Milkwort Jewelflower, 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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