Ornamental grasses can be a wonderful addition to almost any garden or landscape. Thanks to their structural qualities, ability to add graceful movement to a garden, and their colorful and variegated leaf forms, these plants have so much to offer.

Garden of Grasses

An exuberant garden of grasses is quite a sight.

Photo Credit: Mark A. Miller

Mulch around ornamental grass

Wood chips make a nice mulch.

Photo Credit: Wayne Handlos

Ornamental Grass need to be cut back

Here’s an untidy grass clump before it’s cut back.

Photo Credit: Wayne Handlos

Cut back ornamental grass

Here’s the same clump afterward. Stems have been cut back to 4 inches.

Photo Credit: Wayne Handlos

Grasses have the same basic requirements as other garden plants: appropriate light, well-drained soil, an adequate water supply and periodic trimming. They should be planted the same way you would plant any perennial or shrub: Choose a location with adequate light for the needs of the plant, loosen the soil, don’t bury the crown and water well.

The following tips should help keep your ornamental grasses thriving in your garden:

Soil and Fertilizer

Amendments and fertilizers are not usually necessary. If either is added, they may stimulate the grass to grow too fast and the plant will fall over.

Watering

Grasses native to Mediterranean climates (such as ruby grass, autumn moor grass, giant needle grass and all the California native grasses) need extra watering only in their first year to help them get established. Once they are, supplemental watering during dry periods of winter is helpful and would be all that’s needed.

Grasses from other regions (such as Calamagrostis, Miscanthus and Muhlenbergia) benefit from occasional watering – especially during hot, dry periods – for their entire garden life. When watering such grasses, water thoroughly and infrequently – probably not more than once a week.

Mulch

Your grass plantings should be mulched to help conserve water and prevent weed growth. As organic mulches decompose, they’ll release an adequate supply of nutrients for most grasses.

Trimming/Cutting-Back

Many ornamental grasses produce abundant flower stalks that go dormant in winter, and the plants normally benefit from a yearly trim. Trimming can be done anytime. If the flower stalks become unsightly, break apart or fall over, they should be removed at whatever time that happens. In spring, cut back plants just before – or as soon as – new growth appears. The plants should be cut back to within 4-6 inches of the soil level.

Those grasses and grasslike plants that remain green year-round normally don’t need to be cut back except to remove old, dead foliage.


Dividing

If plant clumps become too large, they can be dug up and divided into smaller, more manageable clumps and then replanted. Similarly, if the center of a clump dies out, dig up the clump, divide it and replant the healthy portions.

Pests and Diseases

Ornamental grasses tend to be remarkably free of pests and diseases. Aphids, if they appear, can be unsightly, but they won’t normally cause any serious damage to your plants. They can be controlled with diluted soapy water (1 Tablespoon of dish detergent to 1 gallon of water) or a strong spray of water from the hose.

Gophers and voles may find certain grasses palatable. Control vermin by standard methods, grow the grasses in gopher-proof baskets, or plant species that are unpalatable.

In poorly drained locations, grasses may succumb to crown or root rots. To stop this problem, either improve the drainage with French drains or choose plant varieties tolerant of poor drainage, like Glyceria, Hakonechloa, Molinia and Sesleria caerulea.

Rarely, a grass may develop rust – orange patches on the leaves. If this is a regular occurrence, year after year, switch to another species of grass.

Overall, the better ornamental grasses are remarkably carefree and will provide years of striking beauty in your garden and landscape – give them a try!