Ajuga, also called Carpet Bugle or Bugleweed, makes an excellent groundcover. It is vigorous and adaptable, even doing well in partial shade. It develops a fast-growing, tidy mat of tightly-knit rosettes of colorful foliage, punctuated in the spring with stalks of perky flowers. A perennial, its roots survive winter cold. In some regions its foliage is semi-evergreen, persisting over the winter.
Similar to many fellow members of the mint family, ajuga is sometimes invasive, enthusiastically taking over whole garden beds and sneaking into the lawn. However, the small effort required to control this plant is well worth it. It is otherwise carefree and easy to grow. There are several forms of ajuga that share its virtues. Ajugas are exceptionally hardy, thriving as far north as the Canadian border (zone 3). They are not suited to the climate of the very deep South.
Size: Ajuga grows low to the ground, its leaves forming a mat of individual whorls of leaves from 2 to 4 inches tall. They send out stems which creep above the ground to form new clumps of foliage. In May they send up flower spikes 4 to 6 inches above the foliage. Ajuga spreads as far as it is permitted by means of underground root runners. One version of this plant, Ajuga pyramidalis, does not spread as readily.
Foliage: Ajuga leaves are typically about 4 inches long. They are narrowly oval and glossy. Crinkles in their surface give them an interesting texture. Virtually evergreen, they remain on the plant year round, although they may be dull and dried by late winter. Various ajugas have leaves that are medium green, bronze, pewter, shades of purple and red, or variegated with splashes of cream. They cluster together in rosettes, the leaves of green varieties turning an attractive purple in the fall.
Flower: Ajuga flowers bloom from May to mid-June. The tiny horn, or bugle-shaped, blossoms are tightly ranged along 4 to 6 inch stalks. They are bright blue-purple, rosy-pink, or white, depending on the ajuga variety.
‘Atropurpurea' and ‘Giant Bronze' have bronzy-brown foliage.
‘Burgundy Glow' has variegated red-purple, green and cream leaves, and
‘Alba’ is a white-flowered form.
‘Jungle Beauty Improved’ has large, oval, slightly lobed, semi-evergreen leaves that are glossy, purplish-mahogany and blue flowers. Zones 3-8.
‘Pink Beauty' shows pink flowers on stems of 4 or 5 inches rising from green foliage.
‘Catlin’s Giant’ has large 8 inch long bronze-green leaves, blue flowers.
‘Metallica Crispa' has small crinkled leaves, their purple color having a metallic sheen.
Ajuga genevensis: forms clumps more readily and is therefore less rampant than other ajugas.