Hypericum sampsonii Plant Care

Hypericum sampsonii (Hypericum sampsonii) belongs to the Hypericaceae family within the Hypericum genus.

Hypericum sampsonii displays an upright, bushy shrub growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Hypericum sampsonii produces bright yellow, star-shaped flowers with prominent stamens.

Leaf size: approximately 4 inches.

Water a young or newly planted Hypericum sampsonii 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.

Hypericum sampsonii thrives in full sun to partial shade.

Hypericum sampsonii tolerates temperatures of 50–80°F. Hypericum sampsonii prefers humidity levels of 40–70%.

Well-draining loamy soil with added organic matter for moisture retention. Good drainage is essential for Hypericum sampsonii to prevent waterlogging, which leads to root rot and fungal issues.

Feed Hypericum sampsonii 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.

The PlantoScan app can remind you when to water and when to fertilize each plant.

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.

Hypericum sampsonii 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.

Hypericum sampsonii 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.

Prune Hypericum sampsonii 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.

Hypericum sampsonii 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.

Hypericum sampsonii 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.

See all plants toxic to cats and plants toxic to dogs.

Hypericum sampsonii 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.

Hypericum sampsonii grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. In cooler regions, grow Hypericum sampsonii as a houseplant or bring it indoors before the first frost.