Bugle Weed (Ajuga reptans)

Ajuga, Blue Bugle, Bugleherb, Bugleweed, Bugle Weed, Carpet Bugle

With a wide variety of foliage colors, usually in the rich deep burgundy realm and sometimes with cream and pink edges, ajuga (Ajuga reptans) makes a beautiful groundcover. The foliage is generally crinkled and very glossy as well. However, if you think this is just a foliage plant, you will get quite the surprise as spring eases into summer. Then, ajuga is covered in little spikes of bright blue, purple, pink or white blossoms.

I. Appearance and Characteristics 

Ajuga reptans is commonly known as bugle, blue bugle, bugleherb, bugleweed, carpetweed, carpet bugleweed, and common bugle, and traditionally however less commonly as St. Lawrence plant. It is an herbaceous flowering plant in the mint family Lamiaceae, native to Europe. It is invasive in parts of North America. It is also a component of purple moor grass and rush pastures, a Biodiversity Action Plan habitat in the United Kingdom.

Ajuga reptans is a sprawling perennial herb with erect flowering stems and grows to a height of about 10 to 35 cm (4 to 14 in). The stems are square in cross-section with hairs on two sides. The plant has runners that spread across the surface of the ground. The purplish-green, stalked leaves are in opposite pairs.

The leaf blades are hairless and are elliptical or ovate with a rounded tip and shallowly rounded teeth on the margin. The inflorescence forms a dense raceme composed of whorls of blue flowers, each with dark veins on the lower lip. The calyx has five toothed lobes and the corolla forms a two-lipped flower about 14 to 17 mm (0.6 to 0.7 in) long with a short tube. The upper lip of each flower is short and flat with a smooth edge, and the lower lip is three-lobed, the central lobe being the largest, flat with a notched tip. There are four stamens, two long and two short, which are longer than the corolla and are attached to the tube. The ovary is superior and the fruit is a schizocarp with four chambers.

II. How to Grow and Care

Sunlight

Picking the right site for your ajuga can be variety specific, especially depending on the color of the foliage, Many prefer to grow in shade, but in general, it can handle locations from sunny to shady. The deep, shiny burgundy foliage varieties are a bit more dull and may take on some green in full shade, but they’ll still grow just fine. Overall, the color of the fancy foliage is at its best with a half day of sun.

Temperature and Humidity

Bugleweed does well in a wide range of temperatures, but in very hot, humid areas, it requires good air circulation to prevent crown rot.

Watering

Bugleweed prefers moist soil, so while new plants are becoming established, give them one to two inches of water per week including rainfall. Once established, plants can tolerate some dryness but one inch of water per week should be sufficient. Water whenever the top one to two inches of soil becomes dry.

Soil

Bugleweed prefers medium moisture, well-drained soils with a good amount of organic matter. It will tolerate moderately dry soil.

Fertilizing

Feeding is rarely necessary unless the plant is growing in poor soil. When it is needed, apply an all-purpose granular fertilizer. Or, use a water-soluble fertilizer at a rate of 1 tablespoon per 1 gallon of water. Morning feeding is best, and make sure to rinse off any fertilizer granules from the leaves.

Planting Instructions

Ajugas should be planted in early spring in areas with rich soil that receive either full shade or partial shade (they grow best in partially shady areas). Plants should be spaced 8–15 inches apart. Caution should be used to avoid planting Ajugas too deeply or covering the crown with soil to prevent the crown from rotting. After planting, immediately mulch your ajuga with a layer of shredded bark to keep weeds from smothering these young plants. The space between the plants should fill in within a year or two.

Ajuga is especially ideal for rounding out a pot with other plants because it fills in gaps well. Use a well-draining container and place the plant in an area with good air circulation. Ajuga can form colorful pairs with other perennials like yarrow, campanula, coreopsis, geraniums, or primroses. Since ajuga plants are partially resistant to dry conditions, you can consider companion plants like thrift, creeping thyme, sedum, or hens and chicks.

Pruning

Pruning helps to keep bugleweed under control. Rigorously prune runners twice a year. Be sure to remove any runners escaping the desired planting area. In addition, cut off the flower spikes in late summer after the flowers have faded. To shear back a large area of bugleweed, use a lawnmower set to a high blade height.

If the planting area becomes crowded, thin out the plants in the fall by digging up the entire clump and replanting half of the roots. To control it in your garden beds, stay vigilant about pulling it out from where it doesn’t belong or it will gain a toehold and become a nuisance.

Propagation

Division

Bugleweed is one of the easiest plants to propagate by division. This is best done in spring or fall when there is no chance of frost. Bugleweed spreads by underground runners that form new plants around the parent plant. When the plant colonies become overcrowded or are spreading too aggressively, dig them up, divide and transplant them. Here’s how:

  • Dig up the entire mother plant and surrounding offshoot plants.
  • Separate the plant clumps into individual plants by hand or with a sterilized sharp knife.
  • Discard brown or withered plants.
  • Plant the individual plants in new locations.

Seed

Bugleweed plants are easy to grow from seed. Start seeds indoors in the early spring. Here’s how:

  • Fill small pots with a seed-starter mix.
  • Cover the seeds with a thin layer of compost and keep moist but not soggy; They will sprout within a month.
  • When the seedlings are viable, pot them up into larger containers.
  • Once robust, transplant the seedlings into the garden.

Pests and Diseases

Mostly free of pests and diseases, the only insect that truly likes bugleweed is the aphid, which can be sprayed off the plant with a garden hose.

The other common problem bugleweed could encounter is crown rot, a soil-borne disease that can affect overcrowded plants with poor air circulation. In the South, crown rot is also called Southern blight, and it is caused by a fungus (Sclerotium rolfsii).

This is a problem in humid areas or when the plant is growing in heavy soils. You can prevent crown rot by planting in well-drained soil. If plants succumb to the fungus, they will quickly wilt and die.

III. Types of Bugleweed

  • A. reptans ‘Atropurpureum’ has bronze-purple foliage.
  • A. reptans ‘Chocolate Chip’ has darker leaves than the species plant, including a hint of chocolate brown.
  • A. reptans ‘Burgundy Glow’ has burgundy tri-colored variegated foliage (white, pink, and green).
  • A. reptans ‘Dixie Chip’ is another variety with tri-color variegated foliage (creamy-white, deep-rose, and green) and produces a mat that grows 2 to 4 inches tall.
  • A. reptans ‘Black Scallop’ has perhaps the darkest foliage of all the cultivars with almost-black, scalloped leaves, and deep blue flower spikes. It produces a mat that grows 3 to 6 inches tall. The darkest foliage color is achieved when plants are located in full sun.

IV. Uses and Benefits 

  • Ornamental uses

The carpetweed is adaptable, vigorous plants and useful as ground covers.

They quickly fill bare spots under trees, along garden walks, and tumble from nooks in rock walls and stone steps.

The common bugle is used for erosion control in many areas for its extensive root system which can prevent soil loss.

Ajuga pairs well with Coralbells, the semi-evergreen lobed foliage ground cover plants, and looks good in rock gardens.

  • Other uses

Numerous cultivars have been selected, of which ‘Catlin’s Giant’ has gained the Royal Horticultural Society’s Award of Garden Merit.

Bugle is also known as “carpenter’s herb” for its supposed ability to stem bleeding.

Bugle is a primary nectar source of the pearl-bordered fritillary and the small pearl-bordered fritillary. It is a secondary nectar source of the brimstone, checkered skipper, common blue, cryptic wood white, dingy skipper, Duke of Burgundy, green-veined white, grizzled skipper, heath fritillary, holly blue, large blue, large skipper, large white, marsh fritillary, orange-tip, painted lady, small white, and wood white butterflies.

Ajuga reptans herb has been used in traditional Austrian medicine internally as a tea for the treatment of disorders related to the respiratory tract.

V. Ajuga Companion Plants

Coralbells

Exciting new selections with incredible foliage patterns have put coralbells on the map. Previously enjoyed mainly for their spires of dainty reddish flowers, coralbells are now grown as much for the unusual mottling and veining of their different colored leaves. The low clumps of long-stemmed evergreen or semi-evergreen lobed foliage make coralbells fine groundcover plants. They enjoy humus-rich, moisture-retaining soil. Beware of planting them in areas with very cold winters.

Fothergilla

A North American native, fothergilla deserves a place in every shade garden for its honey-sweet, brushy blooms, fiery fall foliage, and open, airy habit. The tangled branch structure intrigues in winter landscapes. Easy to care for, fothergilla requires no pruning. The leathery leaves have lighter undersides and turn shades of red, orange, and bright yellow in fall.

Bleeding Heart

You’ll quickly realize the origin of bleeding heart’s common name when you look at its heart-shaped pink or white blooms, each with a protruding tip at the base of the blossom. They grow best in partial to full shade in moist, well-drained soil. Some types bloom only in the spring, while others bloom in spring, summer, and fall, provided temperatures aren’t too high.

Bugle Weed (Ajuga reptans) Details

Common name Ajuga, Blue Bugle, Bugleherb, Bugleweed, Bugle Weed, Carpet Bugle
Botanical name Ajuga reptans
Plant type Ground Cover
Hardiness zone 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b
Growth rate Fast
Harvest time Fall
Height 0 ft. 6 in. - 1 ft. 0 in.
Width 0 ft. 6 in. - 1 ft. 0 in.
Sunlight Dappled Sunlight (Shade through upper canopy all day)
Soil condition Clay
Flower color Blue
Leaf color Gray/Silver