Mexican Feather Grass Plant Profile

The Pros and Cons of a Popular Ornamental Grass

Mexican feather grass backlit by the sun.

Christopher Fairweather/Getty Images 

Mexican feather grass has its pros and cons. On the plus side, its stems have a delicate beauty, a beauty enhanced when it sways gracefully in the wind with its feathery flower panicles. But its benefits are practical as well as aesthetic since this ornamental grass is drought-tolerant once it matures. On the negative side, Mexican feather grass is invasive in some regions.

Botanical Name Nassella tenuissima (formerly, Stipa tenuissima)
Common Name Mexican feather grass, Mexican feathergrass, Mexican needle grass, Mexican wiregrass, pony tails, silky thread grass, Texas tussock
Plant Type Perennial ornamental grass
Mature Size 24 inches tall, with a slightly greater spread
Sun Exposure Full sun to partial sun
Soil Type Loamy
Soil pH Slightly acidic to slightly alkaline
Bloom Time Mid-summer
Flower Color Begins greenish, matures to a golden-brown, fades to a tan 
Hardiness Zones 7 to 10
Native Area South America, Central America, parts of the American Southwest

How to Grow Mexican Feather Grass

This ornamental grass spreads readily by seed in some climates. If you live in a climate where it does not spread so easily, you can propagate Mexican feather grass (if you desire more of it for free) by dividing the rootball on a mature plant in mid-spring. 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.

In regions 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. Avoid applying too thick a layer of mulch around its base, as this may cause rot in the plant.

Light

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

Soil

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

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.

Fertilizer

Fertilize annually with compost.

Uses for Mexican Feather Grass in the Landscape

Because 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, it is especially effective to grow several of the plants in a line to form 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 as you would 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 even into winter. In zones 7 to 10, it goes dormant in winter, but the dried stems remain behind. When treated as an annual north of zone 7, this ornamental grass, even though it is dead, furnishes some winter interest.

You can also grow Mexican feather grass in a large container, mixed with other plants. Give its height, it is most effective as the central plant in such 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 it is being grown in a container. But many homeowners with slopes to plant choose to grow Mexican feather grass in the ground because it is helpful in controlling erosion.

Detracting from its usefulness is the fact that Mexican feather grass is an invasive plant in certain parts of the United States (in California, for example, where it is also a fire hazard), even though it is native to other parts of the United States (New Mexico and Texas). Check with your local county extension before planting it to see if it is invasive in your particular region.