Green Alkanet Plant Care

Green Alkanet (Pentaglottis sempervirens) belongs to the Boraginaceae family within the Pentaglottis genus. Green Alkanet is native to southwestern Europe, in northwest Iberia and France. Green Alkanet is also known as Evergreen Alkanet, Alkanet.

Green Alkanet displays a low rosette, spreading ground cover growth habit, reaching up to 0.5 ft tall with a spread of approximately 1 ft. Green Alkanet produces small, bell-shaped blue flowers in clusters.

Leaf size: approximately 2 inches.

Water a young or newly planted Green Alkanet every 5–7 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.

Green Alkanet thrives in full sun to partial shade.

Pentaglottis sempervirens tolerates temperatures of 50–80°F. Green Alkanet prefers humidity levels of 40–70%.

Well-draining, fertile soil with good organic content. Good drainage is essential for Green Alkanet to prevent waterlogging, which leads to root rot and fungal issues.

Feed Green Alkanet 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, fertile soil with good organic content. Avoid low spots where water collects after rain.

Green Alkanet is suited to USDA Zone 5a – 8b.

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.

Green Alkanet can spread to about 1 ft (0.3 m) and reach about 1 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.

Prune Green Alkanet 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.

Green Alkanet is hardy down to USDA zone 5a, so once established it can stay outdoors through winter in that zone and warmer ones.

Water deeply in late autumn before the ground freezes, and spread a 5–8 cm (2–3 in) layer of mulch over the root zone, keeping it away from the trunk.

Young and container-grown shrubs need extra protection: roots in a pot freeze much more easily than roots in the ground.

Green Alkanet can be propagated through seeds, division of rootball.

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

Green Alkanet is susceptible to aphids, spider mites, snails. 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.

Green Alkanet grows outdoors in USDA Zone 5a – 8b. It survives winters down to planting zone 5a. Green Alkanet is native to southwestern Europe, in northwest Iberia and France.