Smallflower St John's Wort Plant Care

Hypericum mutilum L.

Updated · Sources · How we source care data

Hypericum mutilum is a species of St. John's wort known by the common name dwarf St.

Water

Every 7–10 days

Light

Full sun to partial shade

Temp

50–80°F

Humidity

40–70%

At a glance

How do you care for Smallflower St John's Wort?

Plant Smallflower St John's Wort 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.

Where Is the Smallflower St John's Wort Native To?

Native range3 countries

What Is the Smallflower St John's Wort?

Smallflower St John's Wort (Hypericum mutilum) belongs to the Hypericaceae family within the Hypericum genus. Smallflower St John's Wort is native to parts of North America. Smallflower St John's Wort is also known as Dwarf St John's Wort.

Smallflower St John's Wort displays an upright, bushy shrub growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Smallflower St John's Wort produces bright yellow, star-shaped flowers with prominent stamens.

Leaf size: approximately 4 inches.

How Often Should You Water a Smallflower St John's Wort?

Water a young or newly planted Smallflower St John's Wort 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 Smallflower St John's Wort Need?

Smallflower St John's Wort thrives in full sun to partial shade.

Light Requirement

Full sun to partial shade

What Temperature and Humidity Does the Smallflower St John's Wort Prefer?

Hypericum mutilum tolerates temperatures of 50–80°F. Smallflower St John's Wort prefers humidity levels of 40–70%.

Temperature

50–80°F

Humidity

40–70%

What Soil Mix Works Best for a Smallflower St John's Wort?

Well-draining loamy soil with added organic matter for moisture retention. Good drainage is essential for Smallflower St John's Wort to prevent waterlogging, which leads to root rot and fungal issues.

How Often Should You Fertilize a Smallflower St John's Wort?

Feed Smallflower St John's Wort 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 Smallflower St John's Wort?

Choose a spot with full sun to partial shade and well-draining loamy soil with added organic matter for moisture retention. Avoid low spots where water collects after rain.

Smallflower St John's Wort 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 Smallflower St John's Wort?

Smallflower St John's Wort can spread to about 2 ft (0.6 m) and reach about 3 ft (1 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 Smallflower St John's Wort?

Prune Smallflower St John's Wort 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 Smallflower St John's Wort in Winter?

Smallflower St John's Wort 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 Smallflower St John's Wort?

Smallflower St John's Wort can be propagated through softwood cuttings, seeds. Similar propagation techniques also apply to addington's st. john's wort plant care, which shares the same genus.

Is the Smallflower St John's Wort Toxic to Pets and Children?

Pet safety not verified

The ASPCA does not list Smallflower St John's Wort, 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 Smallflower St John's Wort?

Smallflower St John's Wort is susceptible to aphids, scale insects, 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 Smallflower St John's Wort Need?

Smallflower St John's Wort grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Smallflower St John's Wort is native to parts of North America. In cooler regions, grow Smallflower St John's Wort as a houseplant or bring it indoors before the first frost.

Hardiness Zone

Zone 12a

Keep exploring plants

Smallflower St John's Wort 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 Hypericum genus — compare its care with other Hypericum species on PlantoScan.

Hypericum is part of the Hypericaceae plant family — browse all Hypericaceae genera and species.

Smallflower St John's Wort thrives in bright light and direct sun — see other bright-light plants.

More Hypericum Species

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

Sources

  • Scientific name & taxonomy: Hypericum mutilum L., family Hypericaceae (first published in Sp. Pl. : 787 (1753)) — World Flora Online record, IPNI name record.
  • Pet toxicity: Pet safety not verified: the ASPCA does not list Smallflower St John's Wort, 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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