Ajuga

( ah - JEW - guh )

At-A-Glance Information

Also called Carpet Bugle, Ground Pine, Bugleweed, or just Bugle, this genus of low-growers is best in full sun in cooler climates, partial shade in warmer ones, and needs regular water. Ajuga can also take full shade, though the leaves may be a bit more green than purple in lower light conditions. Native to Europe, Africa, Australia and southwestern Asia, these plants form a solid foliage carpet via spreading stolons and bloom from spring through summer. These plants enjoy well-draining soil, and will invade lawn areas if left unbounded. Deer-resistant Ajuga is great for woodland plantings or naturalized areas due to this spreading habit, and is also perfect for smothering weeds or as an erosion-control plant on banks and slopes. The flowers can attract hummingbirds and butterflies to your garden.

Ajuga Species and Varietals

Ajuga is a genus of 40 species in the family Lamiaceae, which makes it a relative of Mint. Ajuga grows best in USDA hardiness zones 3-10 or Sunset growing zones A2, A3 and 1-24. To find your zone, click here: Zone Map.

Ajuga australis (Austral Bugle, Australian Bugle)
This species isn't often seen cultivated in gardens, and is native to eastern Australia. It was first described in 1810 by Scottish botanist Robert Brown, published in his tome Podromus Florae Novae Hollandiae et Insulae Van Dieman. Individual plants reach up to about 6 inches tall and have a spreading habit.

Ajuga boninsimae (Shima-Kako-So, Ogasawara Islands Kako Weed)
This rare species is native to the Bonin Islands of Japan, and reaches 8-12 inches tall. Flowers are white and bloom between December and March. This species was first formally described in 1888.

Ajuga chamaepitys (Ground Pine, Yellow Bugle, Chian Bugle)
This species is similar to Ajuga reptans, Leaves resemble those of rosemary, and are small and thin. This species is native to Europe, the eastern Mediterranean, and North Africa. It reaches between 4 and 16 inches tall, and has yellow flowers which bloom in late springtime. The seeds of these plants can stay alive but dormant in soil for upwards of 50 years.

Ajuga decumbens (Japanese Bugle, Decumbent Bugle)
This species is native to Japan, China, and Korea and is found in lightly forested sunny areas in meadows and along roadsides. This is a groundcover-type Bugle, the leaf layer not exceeding more than 4 inches tall. Flowers bloom between April and June, and are white or purple.

Ajuga genevensis (Upright Bugle, Blue Bugle, Geneva Bugleweed, Blue Bugleweed)
This evergreen European-native plant reaches between 4 and 12 inches tall, and has shallowly lobed or toothed leaves. Flowers can be violet-blue (most commonly), pink, or white. This species commonly interbreeds with Ajuga pyramidalis and Ajuga reptans to produce offspring with quite unique characteristics. Varieties include 'Pink Beauty' (with pink flowers) and 'alba' (with white flowers).

Ajuga iva (Southern Bugle, Herb Ivy, Musky Bugle, French Groundpine, Xantkura)
This species reaches just 2 inches tall on average, and varieties include Ajuga iva iva and Ajuga iva pseudoiva (with yellow flowers). Flowers are purple-pink in the straight species.

Ajuga japonica
This species of Bugle is endemic to Japan, and grows in its native range as a forest-floor groundcover. It is often seen growing in large clusters, due to its ability to self-seed and spreading habit. These plants produce stolons that allow it to grow along the ground and spread. This species reaches between 3 and 8 inches tall and flowers between late April and May. Blooms are very light purple-blue.

Ajuga lupulina
This species is native to grasslands and rocky crevices alongside rivers in the Himalayan Mountain ranges. It grows at an elevation of between 4,200 and 14,500 feet. This interesting-looking species looks a bit like Ajuga pyramidalis, with flowers sandwiched between leaves.

Ajuga orientalis (Oriental Bugle, Eastern Bugle)
This plant is native to the eastern Mediterranean, where it is found in lightly forested areas along the coastline. Usually evergreen, this species can be briefly deciduous in particularly cold winters. These plants reach 1.5 feet tall and wide after between 2 and 5 years of growth. Tubular flowers are white and violet, and leaves are dark grey green.

Ajuga piskoi
First formally described in 1896, this species is native to Greece, northern Macedonia, and Albania, and is found in sunny areas within deciduous forest and scrubland. Flowers are pink, blooming in June and July. This is an endangered species due to deforestation in its native area. It has a sprawling habit.

Ajuga pyramidalis (Pyramidal Bugleweed, Pyramidal Ajuga)
This plant has an upright, mounding habit that gets to 2-10 inches tall and 1.5 to 2 feet wide. This species does not spread by runners. Stems have gray hairs and many round leaves. Violet-blue flowers are not showy, hiding behind the large leaves. Variety 'Metallica Crispa' has reddish-brown leaves that have a metallic glint.

Ajuga reptans (Bugleherb, Bugleweed, Carpetweed, Common Bugle, St. Lawrence Plant)
This is a popular groundcover with dark green leaves that gets to 4 inches high and sprouts 6-inch spikes of blue flowers in spring and summer. Plant these varieties in spring or early fall, about 1 foot apart. These are popular varieties, but are sensitive to root rots and fungal diseases when drainage or air circulation is poor. Deadhead after flowers fade to encourage rebloom and clean up the look of the plant.

'Alba'
This is a white blooming form.

'Atropurpurea'
('Purpurea')
With bronze-tinted green leaves.

'Black Scallop'
Black/purple foliage with scalloped edges.

'Burgundy Glow'
('Burgundy Lace')
Reddish-purple foliage variegated with white and pink.

'Chocolate Chip'
('Valfredda')
Narrow, brown leaves on a slow-growing dwarf plant.

'Giant Bronze'
Deep metallic bronze leaves are very crispy-looking. Grows to 6 inches tall in the sun, 9 inches tall when grown in the shade.

'Giant Green'
Bright green leaves, 6-9 inches tall.

'Jungle Beauty'
Clumps of large, rounded wavy bronze leaves. Flower spikes to 10 inches high.

'Multicolor' ('Rainbow')
Leaves are green, blended with white and pinkish purple.

'Rosea'
With pink blossoms.

'Variegata'
Dense, slow grower with grey green leaves edged and splashed with creamy yellow.

Ajuga turkestanica (Turkistan Bugleweed)
This plant, native to central Asia, usually reaches between 16 and 24 inches tall. Flowers are small and purple, nestled between leaves, and bloom between May and June.

Caring for Ajuga

To plant, choose a spot in the garden that receives full sun or partial shade (the more shade the better if you live in a warm climate). They perform best in the landscape when they get at least a half day of sun, especially varieties with darker leaves. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 4.5 and 7.5 (acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, Ajuga plants appreciate consistent waterings that keep the soil moist but not soggy. As a general rule of thumb, water whenever the top inch of soil feels dry to the touch.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Pruning is not required, though deadheading will help to encourage more blooms and prevent the plant from self-seeding in areas where it is unwanted. Divide plants every few years for health, especially if they are being grown in a cramped area or a container. For instructions on how to successfully divide Ajuga plants, see the Propagation section below. Ajuga plants will live for between 3 and 10 years in the landscape, depending on the variety grown.

Growing Ajuga in Containers
Ajuga, or Bugle plants, can grow either in the ground or in containers. They are compact plants that can be used as filler at the base of a potted arrangement, in a window box mixed with taller plants, or on their own. Choose a container that has adequate drainage holes on the bottom and fill it with a well-draining soil amended with organic matter and perlite. Apply a layer of mulch to the top of the soil to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Ajugas planted in containers will need more frequent irrigation than those grown in the ground; as a general rule of thumb, water whenever the top inch of soil feels dry to the touch and do not allow soil to dry out between waterings. Divide plants every few years for health. For instructions on how to successfully divide Ajuga plants, see the Propagation section below.

Propagation

Ajuga can be propagated either by division or by seed. Simply follow the instructions below to propagate your Ajuga plants.

Propagating Ajuga by Division
Division is probably the easiest way to propagate these plants, and can be done in spring or fall. The idea behind this method is that you are taking an existing clump of live plants and breaking it into smaller segments. This is something you will want to do whether or not you are looking to propagate, as they need to be divided every few years to keep them healthy; otherwise, the roots will become too crowded. To use this method, you will need a clean shovel, clean pruning saw or scissors, extra pots, and well-draining soil to fill the pots. To propagate your Ajuga by division, follow the instructions below:

Identify the area of plants you're going to divide. Start by loosening the soil around the plant with your shovel, working your way inward to avoid causing damage to the roots. Once you've gotten your clump out of the ground, lay it out on its side.
Divide the clump into segments, either with your shovel or with a pruning saw, as many as you'd like as long as there are at least three 'shoots' per segment. Ajuga spreads by underground stolons, so you'll see these runners when you dig them up.
Fill your pot(s) with potting soil and water to ensure that they are draining well. Dig a hole large enough to accommodate the root ball of your division, and place your new plant in the soil. Water generously. Place the pot in a sunny location until you are ready to plant it in the ground the following summer.

Propagating Ajuga by Seed
Before trying this method, keep in mind that propagation by seed does not ensure that you will end up with the exact same plant as you harvested the seed from. If you are looking for an exact clone of the parent plant, propagate your Ajuga by division. To complete this propagation method, you will need to allow the flowers to stay on the plant long enough to come to seed, so do not completely deadhead all of your flowers. Seeds will be mature and ready to harvest in summer or fall, when the flowers have dried and are brown in color. Cut the flower heads off of your plant at this time, and take the seeds out of their pods. To grow Ajuga from seed, follow these directions:

Gather your materials. You will need a pot or seed tray, a spray bottle filled with water and potting soil.
If you are growing just a few seeds, you can use a pot, though if you are growing more than just a few, use a growing tray. Prepare your pot or growing tray by filling it with potting soil.
Place your seeds on top of the potting mix, spaced about 4- 6 inches apart. Sprinkle potting medium over the top until the seeds are covered. As the seeds are starting out, it is best to use a spray bottle to add moisture to avoid uncovering their light soil topping. Keep the soil moist as the seeds develop, using a seed tray cover or plastic to cover your pot to keep moisture in and humidity high.
Continue to monitor for moisture and adequate soil covering until the seeds start to sprout, which should take less than a month, and pot up when they begin to outgrow their containers. Once the chance of frost has passed by, seedlings can be transplanted to a sunny area of the garden in the following spring. Keep the soil moist as the plant develops and enjoy watching your Ajuga spread.

Problems and Pests

The main issue with Ajuga is that it can spread in the garden; to curb this issue, these plants can be contained with edging, which will not allow the underground stolons to migrate any further into areas where they are unwanted. Pests and diseases that can affect these plants include: