Keeping Ornamental Grasses Happy

Ornamental grasses leave little room for complaints in the maintenance department. These few simple steps will keep them looking their best year after year.
Hakonechloa The yellow foliage of Hakonechioa
'Aureola' turns red in fall.

If you don't have an abundance of time to maintain your garden, ornamental grasses are a perfect plant choice. Most species are not picky about soil, though they appreciate good drainage, as do most plants. Once they're established, grasses tend to be fairly drought tolerant, and are susceptible to few pests. Even deer don't find most of them palatable.


Planting Basics

The best time for planting grasses is in the spring or fall. Choose a site with well-drained soil and a sunny exposure. Plant a clump-forming ornamental grass as you would any perennial, giving it a boost of compost or fertilizer and a deep watering. Use 2 to 4 inches of shredded bark as mulch around your plants to help maintain soil moisture.

The planting technique is different for running (or invasive) grasses like banner grasses, European dune grass, giant reed, prairie cord grass, ribbon grass, and basket grass. That's because running grasses venture far and wide by underground and aboveground stems. Though this trait makes them excellent choices for controlling erosion on hillsides, it can wreak havoc in a formal bed. If space is at a premium, plan to restrict running grass growth in some way, such as the method below.

1. Prevention is the best cure for a would-be roving grass. Simply give it close quarters at planting time. Start with a spade, scissors, and a plastic two-gallon nursery container.

2. Dig a hole that is large enough to accommodate the two-gallon pot with its rim situated at soil level. Water the planting spot. Then, cut away the pot bottom and position the pot in the hole.

3. Plant the grass in the bottomless pot (no deeper than the plant was situated in its original container), then firm soil in and around the pot and grass. Water the newly planted grass deeply.

Annual Chores

Leave your grasses standing through winter, then cut them back in spring before the new growth gets going. That way you can have a fourth season of enjoyment from your grasses, which may attract birds to the seed heads in winter.

A sturdy pair of handheld shears makes easy work of pruning smaller grasses. Use electric or gas-powered hedge trimmers for larger grasses or where the clumps have grown dense. Shear off the foliage so that you have at least 2 to 3 inches of the clump remaining for smaller grasses, 4 to 5 inches for larger grasses.

Every 3 to 4 Years

After a few years in the garden, even the slower-growing grasses may grow out of their intended home. By spading off pieces of the parent plant, you can whittle it down to a more manageable size. Plus, you now have additional plants to spread around the garden or give to neighbors.

Divide grasses in early spring before the plant has put on much new growth. Start by shearing off last year's growth, if you haven't already. Using your spade, make a cut in the soil about an inch or so away from the clump. Then make several cuts straight down through the clump to portion off a piece. Lift out the new portion of grass, roots and all. Plant the new piece as soon as possible and fill in the hole you left by the parent plant with a mix of compost and soil.

Grass clumps may die out in the center as the plant ages. Periodic division, as described above, may prevent this, but if not, dig up the clump (in early spring before growth begins) and divide it. Split off a healthy piece of the clump and replant in the original growing site. The remainder of the clump can be broken up and planted elsewhere.