Thunberg's Geranium Plant Care

Thunberg's Geranium (Geranium thunbergii) belongs to the Geraniaceae family within the Geranium genus. Thunberg's Geranium is also known as Thunberg's Cranesbill.

Thunberg's Geranium displays an upright, bushy shrub growth habit, reaching up to 1.5 ft tall with a spread of approximately 1.5 ft. Thunberg's Geranium produces clusters of colorful, five-petaled flowers in various shades.

Leaf size: approximately 3 inches.

Water a young or newly planted Thunberg's Geranium 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.

Thunberg's Geranium thrives in full sun to part shade.

Geranium thunbergii tolerates temperatures of 50–80°F. Thunberg's Geranium prefers humidity levels of 40–60%.

Well-draining soil with a mix of loam, sand, and perlite. Good drainage is essential for Thunberg's Geranium to prevent waterlogging, which leads to root rot and fungal issues.

Feed Thunberg's Geranium every 4 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 part shade and well-draining soil with a mix of loam, sand, and perlite. Avoid low spots where water collects after rain.

Thunberg's Geranium 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.

Thunberg's Geranium can spread to about 2 ft (0.5 m) and reach about 2 ft (0 m) tall. Space plants about 2 ft (0.5 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 Thunberg's Geranium 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.

Thunberg's Geranium 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.

Thunberg's Geranium can be propagated through stem cuttings, division, seeds. Similar propagation techniques also apply to spiny geranium plant care, which shares the same genus.

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

Thunberg's Geranium is susceptible to aphids, spider mites, whiteflies. 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.

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