Mexican Feather Grass: Plant Care & Growing Guide

Mexican feather grass has its pros and cons. On the plus side, its stems have a delicate beauty—they grow 18 inches to about 2 feet tall—a beauty enhanced when they sway gracefully in the wind with their feathery flower panicles.

Its benefits are practical and aesthetic since this moderate-growing ornamental grass is drought-tolerant once it matures, loving the full sun and tolerating partial shade. Mexican feather grass seedlings do best when planted in the spring. This plant is a perennial in USDA zones 7 through 10, returning year after year. And in its most ideal zones, it self-seeds.

On the negative side, Mexican feather grass is invasive in some regions and is officially listed on the invasive species list for California. In areas where the plant is invasive, growing Mexican feather grass requires a great deal of landscape maintenance because you will need to continually remove the seedlings from spots in your yard where you do not want them growing.

Mexican Feather Grass Care

The dense, fountain-shaped clumps of Mexican feather grass stems have a fuzzy appearance; they soften hardscape features in the landscape and make them more welcoming. For this purpose, growing several plants in a line is especially effective for forming a border (for example, along a patio). Its light color (the leaves are a silvery green to lime-green) makes it a good foil for darker plants, for which the plant can be used as a backdrop. It is also a good plant to use in borders for cottage gardens.

Although Mexican feather grass does flower, treat it like any other foliage plant, complementing it with flowering plants. As a plant primarily grown for its foliage, it offers visual interest across multiple seasons, including winter. When treated as an annual north of zone 7, the plant will die but still has winter interest with big brown tufts. It goes dormant in winter in zones 7-10 and will eventually send up new green growth in spring.

Many homeowners with slopes to plant choose to grow Mexican feather grass because it helps control erosion.

Light

While the plant can survive in partial sunlight, Mexican feather grass performs best in full sunlight.

Soil

Plant Mexican feather grass in loamy soil since it needs good drainage. If your soil is not loose enough, loosen it up by using sand and organic matter.

Water

Mexican feather grass has low-to-average water needs. Once established, it is drought-tolerant. Mexican feather grass copes with droughts by going into dormancy.

Temperature and Humidity

Mexican feather grass isn't a great lover of hot summery weather. It doesn't die out, but it tends to lose color in the warmest, most humid months. Mexican feather grass is winter hardy, tolerating cold temperatures to about 0 degrees Fahrenheit; however, any colder than that for a sustained amount of time will kill the grass.

Fertilizer

Fertilize Mexican feather grass annually with a good layer of compost.

How to Get Rid of Mexican Feather Grass

If growing conditions are right, Mexican feather grass can overgrow in an area and overtake your other plants. Once it's established, the problem is challenging to control. Two ways to remove Mexican feather grass are physical and chemical removal. You can physically remove it by hand weeding or strategic grazing. Mowing has the opposite effect; it becomes a seed dispersal method versus removal.

Chemical control methods include potent herbicides like glyphosate or hexazinone, which have a 76 to 100% success rate and might need more than one application. According to the Texas A&M extension service, research from Australia shows success when individual plants are foliar sprayed with glyphosate at 1.5 percent or soil-applied hexazinone at 2 ml per plant.

Pruning

Mexican feather grass doesn't need pruning, but you may want to trim away dead flowers and overgrown stems at the end of the season, as you tidy them up for dormancy. Use a clean, sharp garden shears and clear away the debris, so the detritus doesn't accidentally reseed.

Propagating Mexican Feather Grass

Mexican feather grass can be propagated by sowing seeds or division. Division is best done in the spring before your grass sends up any new shoots of growth. Dividing is an excellent way to break up large clumps. Here's how to propagate Mexican feather grass.

1. You will need a shovel or trowel to lift out the plant and a clean, sharp spade to divide the plant, and compost.
2. Measure about an inch from the outer edge of the clump and dig a circle around the entire clump, going at least 6 inches down. Using the shovel, dig out the whole clump with its root ball.
3. Place the clump on its side, and cut it into half or thirds using a sharp spade, depending on how large it is.
4. Pick the new spot, dig a hole twice the size of the root ball, and line the bottom with compost. Put the rootball in the hole with the plant's crown lying just below the soil line. Fill in the hole with soil.
5. Water well.

How to Grow Mexican Feather Grass From Seed

Nassella tenuissima does well when planted from seed if you start your seeds indoors in the early spring. Place on a layer of potting mix, then cover with a thin layer of the same potting mix, soil, or sand. Water regularly; plant outside when sturdy.

Potting and Repotting Mexican Feather Grass

You can also grow Mexican feather grass in a large container mixed with other plants. Given its height, it is most effective as the central plant in a mixed planting. Surround it with shorter plants that enjoy full sun and sharp drainage. Be especially careful to avoid overwatering Mexican feather grass when grown in a container.

Overwintering

Mexican feather grass will not survive in areas that experience frosty winters. You can keep it alive If it's in a container and can move to a frost-free area or under a cold frame for the winter. Some animals may forage from Mexican feather grass if you leave it in the ground over the winter.

Common Pests and Plant Diseases

The plant is not often bothered by diseases or insect pests, although aphids and leaf spot occasionally plague it. Deer and rabbits tend to leave it alone.

Common Problems With Mexican Feather Grass

Mexican feather grass is a low-maintenance, easy grower. It doesn't have too many problems, resisting most diseases and pests.

Overgrowing an Area

One of the biggest complaints with this plant is that it can overtake an area of foliage or other plantings. To manage it by hand, pull up Mexican feather grass plants in the spring, right before it begins creating new green shoots. Herbicides are another remedy. Also, if you like the look of this plant, but are worried about having a spreading plant in your garden or lawn, buy it from nurseries as an "infertile cultivar." It will produce sterile seeds.

Grasses Laying Flat

If your Mexican feather grass starts falling flat or "lodging," it could be a sign of insufficient water, entering dormancy in the winter season, or overfertilization (too much nitrogen in the soil). If it's the active growing season, water the grass, although ensure the soil drains well and is not soggy. Also, feed these grasses only once per growing season; springtime is usually best. If the grasses have grown too big or the clump is too dense, usually after three years or so, divide the clump.

Grass Turning Brown

As temperatures cool, you may notice browning beginning to occur on the tips. It is starting to die back in preparation for going dormant. If during the growing season, it can also be a sign that the temperatures are too hot, and the plant does not have enough water to prevent scorching.