Pentaglottis sempervirens (Green Alkanet)

Pentaglottis spp.

Attracts Pollinators Attracts Butterflies Deer Resistant

SunPart Shade – Full Shade

HardinessZones 6–9

Overview

Pentaglottis spp. is a genus in the borage family represented chiefly by Pentaglottis sempervirens, a coarse, bristly evergreen perennial native to southwestern Europe. Plants form a basal rosette of large, oval to lance-shaped leaves 4-16 inches (10-40 cm) long, roughly textured with stiff white hairs, from which branched flowering stems rise 24-39 inches (60-100 cm) tall. From spring into summer the stems carry small five-lobed flowers about 0.4 inch (10 mm) across, vivid blue with a white center, resembling those of forget-me-not and borage. The genus grows from a thick, deep black taproot that stores reserves and resprouts after the top is cut. Pentaglottis spp. grows in partial shade and moist, fertile soil along hedge banks, woodland edges, and shaded roadsides. Beyond its native range in Spain, Portugal, and southwestern France it has naturalized widely across the British Isles and other parts of temperate Europe, where it persists in gardens and waste ground. Seed is set freely and the brittle taproot snaps when pulled, so established colonies regrow from root fragments and spread steadily. The bristly foliage can irritate skin on contact. The blue flowers draw bees and other long-tongued insects through the cooler months of the growing season.

Native Range

Pentaglottis spp. is native to southwestern Europe, in Spain, Portugal, and southwestern France. It has naturalized across the British Isles and other parts of temperate western Europe, where it grows on hedge banks, woodland margins, and shaded disturbed ground.

Suggested Uses

Pentaglottis spp. is used in shaded wildlife and cottage plantings, on hedge banks, and in informal woodland-edge borders where early bees forage. Its spreading, self-seeding habit suits naturalized rather than formal settings.

How to Identify

Look for a rosette of large, rough, bristly oval leaves and upright branched stems to about 39 inches (100 cm). The small five-lobed flowers are bright blue with a white throat, borne in coiled sprays through spring and summer. A thick black taproot and stiff white hairs on the foliage separate it from true forget-me-nots.

Appearance

Size & Dimensions

Height2' - 3'3"

Width/Spread1'6" - 2'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~12 weeks

Spring Summer

Flowering runs from mid spring into summer, roughly April through July, with scattered later blooms. The blue, white-eyed flowers open a few at a time along coiled cymes that uncurl as they mature. Bees and other long-tongued insects visit the flowers.

Detailed Descriptions

Flower Description

blue with a white center

Foliage Description

dark green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Tolerates up to 6 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)

357912

Soil Types

clay loam silt

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

1-2 years from seed

Care & Maintenance

Care Guide

Pentaglottis spp. grows in partial shade to full shade and moist, fertile soil, tolerating a wide range of conditions including heavy clay. The genus is drought-sensitive in full sun but otherwise needs little care once established. The deep taproot makes mature plants hard to move or remove, since severed roots regenerate. Plants self-seed freely and can spread beyond their intended area in cool, moist gardens. Cutting back after flowering reduces seeding. The bristly foliage and stems can cause skin irritation on contact.

Pruning

Cut flowering stems back after bloom to limit self-seeding and tidy the rosette. Remove faded foliage as needed through the season. Plants regrow from the crown and taproot after cutting.

⚠️ Toxicity Warning

Unknown

Perennial