March / 2009
At Home in the Garden

Breaking the rules with groundcover
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Is it a perennial or is it a groundcover? Are all groundcovers perennials?

In my dictionary, the word plant is never mentioned when you look up the definition of perennial. Officially, we should be saying perennial flower or perennial plant to differentiate.

Groundcover, on the other hand, in my dictionary is defined specifically as a plant that is low-growing; it may form a dense cover and can grow extensively.

I do on occasion use what is officially considered a perennial flower as a groundcover or an official groundcover as a perennial. The spot has to be just right and I always have a reason for breaking the rules of tradition.

Ajuga or bugle weed
One very popular groundcover is ajuga or bugle weed. It is traditionally always found in the groundcover section at your local garden store, and is almost always used as a groundcover in the garden. However, in my garden, ajuga is used in small groupings like a perennial flower.

Ajuga reptans is most often called ajuga and does make a beautiful and impressive groundcover display. Ajuga grows only 4 to 10 inches tall, and depending on the cultivar it can spread extensively in its preferred habit of partial shade and well-drained soils.

One way I have found of keeping it in check in my garden is by planting it in deep shade, which is also typically very dry. I have also used a small planting of ajuga near a stone walk where the color is an excellent contrast to the stone. It stays in bounds because it is bordered by a dense planting of other perennials.

The leaves are simple, can be glossy and often dark green with highlights of purple, and the leaves are somewhat lettuce-like in habit and texture. Many of the cultivars I have observed are not quite as vigorous as the species, so they tend to not be as aggressive in their spreading habit, which I consider a plus.

Flowers of ajuga add an additional 4 to 6 inches in height to this groundcover when present, and can range in color from violet blue to pink and white, depending on cultivar. It begins to bloom in mid to late May or June, making an impressive show in the garden before most of the other perennial flowers bloom. I do not have huge masses of ajuga in my garden, so I deadhead the flowers once flowering is complete to remove the potential for seed production, but mainly because it just looks better in my garden.

You can also use ajuga as an unusual filler foliage in container gardens and window boxes in the summer or fall with pansies and ornamental kale. I especially like the texture and colors of the ajuga in a fall container display, where the displays are a little simpler and it doesn’t get so lost.

Planting ajuga
Well-drained soils are a must when planting ajuga because crown rot can be a big problem where the soils are constantly or periodically wet. Ajuga can also be considered expensive in my opinion in comparison to other groundcovers, and in the beginning it spreads rather slowly. So if you are planting it in large masses, make sure the areas in which you are planting it are prepared properly in order to protect your investment.

Paying attention to garden rules is a good thing when you are considering the cultural requirement to grow plants in your garden. The design and placement of these plants is where breaking all the rules is the best way to have a garden that is both beautiful and uniquely your own.