Ornamental grasses look good throughout the seasons and provide texture and movement in the garden too. Grasses are selected for their attractive foliage, distinctive form, and/or showy flowers and seedheads. Make sure that the grass selected fits into the landscape plan. It must be the right size, shape, color, and needs to bloom in the correct season. Here is an overview of how to plant and grow ornamental grasses successively in the garden as well as a list of ornamental grass varieties that would be good to plant for great autumn color.
When: The best time to plant grasses is spring, so they will be established by the time hot summer months arrive. Container-grown grasses can be planted during the summer as long as adequate moisture is supplied. Cool-season grasses can be planted in early fall, but plenty of mulch should be used to protect fall plantings from winter kill.
Soil: Most grasses will grow in good or heavy clay soils. Those that have special soil requirements should be found on the print label when purchased.
Spacing: A general rule is to place plants as far apart as their eventual height. Grasses that have a mature height of 3 feet may be placed 3 feet apart from center to center. If quick cover is desired, and your budget allows, plant closer.
Planting: Keep the following guidelines in mind when planting ornamental grasses.
- Always try to match the original soil line of the plant.
- Do not plant too high or too low below the crown.
- Newly planted grasses are susceptible to drying out, so water them immediately after planting, and keep them well watered until they are established.
Mulching: Mulching is important to get your grass plant off to a good start. Mulch reduces weeds, conserves soil moisture, reduces soil temperature, and provides winter protection. A two-to-three-inch later of organic mulch is best.
Watering: Except in extreme periods of drought, most established grasses should receive enough rainfall in Kentucky without supplemental water. Drip irrigation, applied directly to the root zone, is best during flowering because overhead irrigation may cause rapid decline of flowers.
Cutting back foliage: Ornamental grasses should be cut back just before or as the new season’s growth begins to appear. For most grasses in Kentucky, cut back ornamental grasses in late February or March. This will allow you to enjoy the attractive tan and reddish foliage during the winter months Most grasses should be cut back to a few inches above the ground. A pair of hand pruners or string trimmers will work for most plants. However, most species that grow more than 10 feet tall will have large, woody stems that can be cut only with a string trimmer blade attachment, pruning saw, or chainsaw.
Dividing and transplanting: Grasses may need to be divided or transplanted to propagate more plants, renew older clumps that tend to die within the center of the clump, or move plants to a better location. Warm-season grasses should be divided in late fall, winter, or early spring. Divide the plants into good-sized divisions with multiple tillers (stems). They can be divided into smaller divisions, but these require more time to reach mature size. Keep newly divided plants moist and shaded until planted in their new location.
For more information on ornamental grasses for the Kentucky Landscape, contact your local Extension Office.
Information from this article was taken from Ornamental Grasses for Kentucky Landscapes, HO-79.