Pentaglottis sempervirens: complete guide

Overview

Pentaglottis sempervirens, commonly known as evergreen bugloss or green alkanet, is an energetic plant native to southwestern Europe. This established ground cover is ideal for difficult spots with part shade, and equally at home in full sun. The name refers to the five (penta) languages (glottis) in which it's known across Europe.

The plant grows low and spreading, typically 30-50 cm tall and regularly extending 1-2 metres or more across. It's a vigorous grower, occasionally even too vigorous, but ideal if you need substantial ground coverage without fuss.

Appearance and flowering

The plant forms a dense mat of large, dark-green, bristly leaves. These leaves remain visible year-round, hence the name "sempervirens" (evergreen). The leaves are lance-shaped to oval, heavily bristled, and give the plant a robust, rustic appearance.

From April through June, countless tiny deep-blue flowers appear in spiralling spikes. These flowers are truly stunning - an intense blue that practically jumps from the green foliage. After flowering, small seeds develop.

Ideal location

Evergreen bugloss grows anywhere you plant it, from part shade to full sun. The real advantage is that it's one of the few ground covers tolerating part shade beautifully - perfect under trees or against north-facing walls. In full sun it flowers slightly more abundantly, but splendid results appear even under trees.

The plant is remarkably adaptable and unfussy about location.

Soil

Pentaglottis grows in almost any soil, from heavy clay to sand. It tolerates both dry and wet soil. Organic matter is helpful (adds nutrients) but unnecessary. The pH can be anything from acidic to alkaline.

Important: ensure reasonably well-drained soil - not permanently waterlogged, otherwise roots may rot during very wet winters.

Watering

Once established, evergreen bugloss is extremely drought-tolerant and requires almost no watering. Water only during extreme summer drought or when the plant is very young. Normal rainfall usually suffices.

The plant also tolerates wet soil well, provided it's not permanently waterlogged.

Pruning

Pruning isn't really necessary. The plant maintains itself admirably. If the plant becomes too vigorous (which can happen with success), you can cut it back after flowering (June) or in early spring (March). Remove dead foliage in early spring.

The plant self-seeds easily, which is sometimes an advantage (free plants) and sometimes a challenge if it produces too many seedlings.

Maintenance calendar

January-March: Remove dead leaf material. Pruning possible for shape.

April-May: Flowering period. Enjoy the blooms. No feeding needed.

June-July: Flowers finish. Plant can be cut back for neatness.

August-September: Growth and preparation. Seedlings may appear.

October-November: Plant slows. No care needed.

December: Winter rest in northern climates.

Winter hardiness

Evergreen bugloss is extremely winter-hardy to at least -15 degrees Celsius. It regrows from the roots if top growth is damaged by frost. Throughout northern Europe (including the UK and beyond) it overwinters perfectly outdoors.

Companion plants

Evergreen bugloss looks lovely mixed with other early-flowering ground covers: forget-me-nots (Myosotis), hellebores (winter roses), glory-of-the-snow (Chionodoxa), Pulmonaria, and speedwell (Veronica). Or plant it alone for uniform blue spring flowering.

In full sun it combines beautifully with other blue flowers: Veronica, delphiniums, and blue phlox. In shade: forget-me-nots and hellebores.

Closing thoughts

Pentaglottis sempervirens is a highly practical, easy ground cover you can plant almost anywhere. The combination of robust nature, year-round foliage, and stunning spring flowers makes it valuable in any garden. It's a workhorse you needn't worry about - plant it and forget it. You'll find potted plants at most garden centres.