Plant Answers

Weekly Express-News Article
Saturday, April 1, 2006
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist
“Groundcovers for the Shade”

Groundcovers are an important part of a low water use landscape. They take less water and less maintenance than lawn grass. Use groundcovers for the part of your landscape that you want a planting where there will not be much traffic. A flagstone or brick path (without mortar) winding through the groundcover allows you to easily traverse the planting and is an attractive landscape feature.

We often turn to groundcovers in landscapes where there is too much shade for lawn grass. Asiatic jasmine, English ivy, dwarf ruellia, monkey grass and liriope make good low groundcovers for shade. For a taller groundcover consider Texas gold columbine, shrimp plant, Turks cap, and blue plumbago.

Asiatic jasmine is the favorite groundcover for sun or shade. If it is allowed to grow untrimmed, it forms rolling mounds 12 to 18 inches tall. The plant is very versatile, however, and can be managed with a string mower to have a manicured look with straight edges at any height from 4-18 inches tall. The evergreen leaves are shiney dark green, and the planting becomes so thick that weeds are not a problem. Live oak suckers that emerge look so much like Asiatic jasmine that they only need be trimmed out once per year. Asiatic jasmine does not have any disease or insect pests. Deer will usually not eat from an established bed. In some cold winters the foliage may burn but a run through with the lawn mower at its highest setting in early spring (now) will remove damaged leaves.

If Asiatic jasmine has a negative characteristic it is that it is relatively difficult to get it established in the landscape. Inexpensive rooted cuttings are available but it can take 3 growing season before you have the solid planting that you desire. A good strategy is to use one gallon plants placed 2 feet apart to achieve a thick planting after 1 growing season. Water at the same rate you would for your lawn that first year. After the initial year, supplemental water is not required. Fertilize with slow release lawn fertilizer in April and September for a fast start.

In years past we used to think that replacing a lawn with groundcover required that the sod be dug up, including the roots. There is a better way. Spray the actively growing lawn grass with Round-up or Finale this spring and then plant the groundcover into the killed sod. The sod gradually decomposes but for part of the first growing season it serves as a good mulch to reduce weed growth while the jasmine establishes itself.

English ivy grows much faster than Asiatic jasmine. Rooted cuttings planted on 2 foot centers, fertilized and irrigated at the rate recommended for jasmine will fill in the area by the end of the first growing season. Deer love ivy so only use it where the hungry pests are not present. In wet years English ivy will sometimes also develop foliage diseases. The planting usually recovers after the weather dries.

Monkey grass and its larger cousin, liriope, make spectacular groundcovers for deep shade. They look like turf but do not require mowing, watering (after establishment), or pesticide applications. A planting of liriope around a shade tree surrounded by a bed of Asiatic jasmine pruned flat has a very neat and formal look.

Dwarf ruellia is a blooming groundcover. The Katy selection has quarter size tubular purple-blue blooms and Belinda has pink blooms. There is also a white blooming selection. The plant makes a 12 inch tall groundcover for sun or shade. The more sun, the more bloom, but even with reduced bloom it is still an attractive groundcover in the shade. Four inch plants planted on 1 foot centers will fill in a bed within the first growing season. Dwarf ruellia is not a favorite deer food but they will eat it in a drought, especially if it is irrigated.

If you have a large shady area to cover consider using one of several larger groundcovers for part of the planting. Texas gold columbine is especially spectacular under deciduous trees. It has yellow “shooting star” blooms in the spring and soft green foliage (18 inches) the rest of the year.

Shrimp plant, Turks cap and blue plumbago also make good tall groundcovers for the shade. They bloom from spring through late autumn. The hummingbirds will visit your columbine, Turks cap and shrimp plant groundcovers. Plumbago is a special favorite of butterflies.