Threadgrass: You Can Grow That

It sounds too good to be true: an ornamental grass that loves heat and looks beautiful all year gently swaying in the wind. But threadgrass (Nasella tennuissima) fits the bill — and is waterwise. This pretty low-water plant also is called silky thread grass or Mexican feather grass.

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Can you spot the tightrope-walking lady bug on this threadgrass?

Texture and movement can add to a garden’s design nearly as much as shape and color. Threadgrass has a delicate, windswept form that serves as an attractive backdrop to low-growing flowering plants like sedums or verbena. In summer, the grass is a nice green with feathery ends. In winter, the airy flower heads take on a golden, wheat-like appearance. Threadgrass is deer resistant, has no known diseases or pests, and is a native plant that grows in zones 5 through 10.

Planting Threadgrass

Plant threadgrass in spring, summer or fall. Because it likes heat, you might be able to fill in a summer bare spot with threadgrass after weather is too hot for most garden plants. If you want a swaying meadow effect, you’ll need to plant a few, and then wait for them to reseed. If you want immediate effect, plant several. Just keep in mind the plant grows to about 12 inches wide.

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Young threadgrass plants that came up next to their mother plant.

Your threadgrass plants should reach about 18 to 24 inches high when fully grown, sometimes higher when blooming. Plant it in full sun and in most any kind of soil. When you first plant or transplant your threadgrass, give it a little extra water, especially in high heat.

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You also can bunch threadgrass for a meadow effect, like the grass in this Austin area garden.

Caring for Threadgrass

Once threadgrass is established, it should need nothing but rain water to grow and set seed. The plant is  a short-lived  perennial and should come back several years in a row, assuming typical low temperatures for the lower zones. It also reseeds (see below), creating new plants nearby. You can leave these to eventually replace the established ones, or dig them up and transplant them to another spot in your garden. They are easy to recognize.

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Tiny seedlings of threadgrass are easy to spot around other plants. Depending on where they show up and where you live, they are either free plants or invasive ones.

Each spring, as you begin pruning other plants in your garden, gently comb the grass blades with a fine rake and trim them for shape.

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How perfect is the texture of the fine stems of threadgrass as part of this xeric plant grouping!

Caution for Some Gardeners

The fact that threadgrass replaces itself by sprouting tiny plants from seed is a bonus to me. We get just enough seedlings to move around our garden, without them being a problem. But in some areas, threadgrass can be invasive, reseeding in places where it interferes with other plants. In fact, the  plant is prohibited in California because it is so invasive there and can crowd out grasses native to coastal areas. It also can crowd out pasture grasses. We have had no problems with that, however, and have only seen the plants pop up near mature ones.

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Ornamental grass like threadgrass is great for lining pathways.

Not sure yet? Check out the short video of the grass moving in the winter breeze I posted on Southwest Gardening Blog’s Instagram page.

Enjoy growing threadgrass and other ornamental grasses in your low-water garden!

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