Silverleaf Phacelia Plant Care

Silverleaf Phacelia (Phacelia argentea) belongs to the Boraginaceae family within the Phacelia genus. Silverleaf Phacelia is native to the coastline of southwestern Oregon and far northwestern California.

Silverleaf Phacelia displays a low rosette, spreading growth habit, reaching up to 1.5 ft tall with a spread of approximately 1 ft. Silverleaf Phacelia produces small, bell-shaped flowers in shades of blue, purple, or white.

Leaf size: approximately 2 inches.

Water a young or newly planted Silverleaf Phacelia 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.

Silverleaf Phacelia thrives in full sun to partial shade.

Phacelia argentea tolerates temperatures of 50–80°F. Silverleaf Phacelia prefers humidity levels of 40–60%.

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

Feed Silverleaf Phacelia 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 sandy loam with added organic matter. Avoid low spots where water collects after rain.

Silverleaf Phacelia 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.

Silverleaf Phacelia 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.

Prune Silverleaf Phacelia 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.

Silverleaf Phacelia 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.

Silverleaf Phacelia can be propagated through seeds. Similar propagation techniques also apply to phacelia adenophora plant care, which shares the same genus.

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Silverleaf Phacelia is susceptible to aphids, spider mites, thrips. 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.

Silverleaf Phacelia grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Silverleaf Phacelia is native to the coastline of southwestern Oregon and far northwestern California. In cooler regions, grow Silverleaf Phacelia as a houseplant or bring it indoors before the first frost.