Photo courtesy of John Hoffman
It was already my favorite grass, and then the photo from Piet Oudolf's garden grabbed me and wouldn't let go. The photo shows a large, metal trough filled with Mexican Feather Grass. John Hoffman captured the shot in the fall of 1996 while visiting Piet's garden in the Netherlands. The grass in the photo looks so lush, soft and inviting that I wanted to walk into the photo and touch it. "I've got to have that grass," I thought.
Name: Nassella tenuissima
Common name: Mexican Feather Grass
Hardiness: Zones 7 to 10
Mature height: 1½ feet; 2 feet with flower
Mature spread: 1½ to 2 feet
Classification: Native grass
Landscape use: Rock gardens, scree gardens,
xeric landscapes and containers. Works well in
mixed perennial plantings and in color beds or
containers where not hardy.
Ornamental characteristics: Fine-textured,
lime-green foliage and blonde seed heads.
Graceful, upright habit with flowing foliage tips
that create movement in the landscape.
Working at a nursery that specializes in ornamental and native grasses, I've seen a lot of varieties. Nothing else looks and moves like Nassella tenuissima. Its ultra-fine foliage catches the tiniest hint of a breeze and comes alive with motion. The flowing habit has a softness and texture that is both visual and tactile. When we take it to trade shows, it's the plant everyone touches.
Mexican Feather Grass is native to dry, rocky slopes and open grasslands in the south-central U.S., northern Mexico and southern South America. With a background like that, it is adapted to drought and thrives in well-drained soils. Conversely, it does not tolerate water-logged soils; cold hardiness drops in poorly drained soils, particularly in colder climates. This grass is a sun lover. It can take very light shade, but full sun produces the best flowering and form.
Interestingly, Nassella tenuissima is a cool season grass. It has a flush of lime-green foliage in early spring, followed by silvery inflorescences in late spring (early summer in cooler climates). With rising temperatures, Mexican Feather Grass enters a period of dormancy, which it handles gracefully. The foliage turns straw-colored, and the form, texture and flowing habit remain appealing. I find that combing out the spent blooms prevents matting. As temperatures cool down in fall, N. tenuissima gets another flush of growth that carries into winter.
The fountain-like, flowing habit on Mexican Feather Grass is accentuated by its unusual inflorescences. They're borne on the tips of the foliage, where they emerge silvery-gold and age to a wheat-straw blonde. The blooms aren't stiff and upright; rather, they weep gracefully. Nassella tenuissima may re-seed under hospitable conditions but can be controlled in managed landscapes.
Photo courtesy of Shannon Currey
I tend not to cut back Mexican Feather Grass until necessary. I like the mingling of green and blonde foliage. At some point, the blonde foliage will dominate, and a cutback will rejuvenate it. Do so right before a flush of growth - late winter or late summer.
Nassella tenuissima looks particularly at home in rock gardens and xeric landscapes. Its wispy, threadlike foliage contrasts beautifully with stones and hardscape, and the flowing habit spills fetchingly over walls or container edges. Because it's my favorite, I have it planted throughout my Zone 7 landscape. It looks fantastic in my raised bed full of sun-loving, drought-tolerant perennials, where it softens the hard, brick edges. In climates where Mexican Feather Grass isn't hardy, I think it's worth planting for a single growing season. It thrives in the well-drained media of containers - I'm lucky enough to use it year-round in combination planters.
That brings me back to the picture of Piet Oudolf's trough. I love it because it captures the enormous appeal of Mexican Feather Grass. And now, after looking at the photo for years, I've decided it's time to follow through with a really spectacular planting. Anyone have a spare trough?
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