Big muhly is a suitably named ornamental grass. This dramatic member of the muhly grasses can make a big statement in desert landscapes. Here’s how to grow and care for this Texas native.
Big muhly (Muhlenbergia lindheimeri), as the name implies, is a sizeable ornamental grass. It has foliage that ranges from light green to blue-green, which is why it is also called blue muhly. In the fall, it sends up elegantly arched seed stalks covered in creamy white flowers that gradually fade to tan.
This grass is most effective when planted in drifts, but also makes an impressive specimen plant if you only have room for one. It gives a cooling effect to the garden and softens the harshness of boulders, cactus, and other spiky plants.
If you love the look of dramatic ornamental grasses, big muhly is a good alternative to pampas grass (Cortaderia selloana) or fountain grass (Pennisetum setaceum), both of which are considered invasive in the southwest.
Why I Like This Plant
- Beautiful cream-colored plumes
- Low water use and low maintenance
- Birds build nests with the foliage
- No thorns, non-toxic, non-invasive
Optimal Growing Conditions
If you’re thinking of adding big muhly to your garden, you need to find a suitable place that will keep your plant healthy and looking good… while minimizing maintenance for you.
Here are the key factors to keep in mind.
Temperature
Big muhly should be grown in USDA Hardiness Zones 7 – 11. It is cold-hardy down to around -10°F and, as a native to Texas and Mexico, easily handles extreme heat.
Sun Exposure
Big muhly performs best in full sun but tolerates some light shade.
Size and Growth Rate
Big muhly is a fast grower that reaches a size of 5 feet tall and 4 feet wide, usually within the first two years. Its seed stalks can grow up to 6 feet tall. It’s one of the largest landscape muhly grasses, so be sure to give this plant plenty of room so that it can reach its full potential.
Soil
Big muhly is not fussy and grows in sandy, rocky, or clay soil, provided it’s well-draining. As a southwest native, it tolerates alkaline limestone soils.
Other Location Considerations
Since it has no thorns and produces minimal litter, it’s a plant you can feel comfortable placing near a pool or sidewalk, or anywhere it might come in contact with pets and people. The wispy inflorescences are not spiky, irritating, or toxic. But note that it will be messy when it comes time to remove old dead growth.
If you like the look of big muhly but are concerned it may be a little large for the space you have in mind, consider deer grass (Muhlenbergia rigens). It looks like a somewhat smaller version of big muhly.
Big Muhly:
The Essentials
| Common Name | Big muhly |
| Scientific Name | Muhlenbergia lindheimeri |
| Origin | Texas, Mexico |
| Plant Type | Bunch grass |
| USDA Zones | Zones 7 – 11 |
| Cold Hardy | To -10℉ |
| Flower Color | Cream |
| Flower Season | Late summer, fall |
| Mature Size | 5’ high x 4’ wide |
| Growth Rate | Fast |
| Sun Tolerance | Full sun |
| Water Needs | Low to moderate |
| Pests & Diseases | None |
| Garden Friendly | No thorns, non-toxic, not invasive |
| Wildlife | Attracts birds Deer resistant |
How to Plant
The rule of thumb when planting any ornamental grass is to dig a hole three times as wide as the root ball but no deeper. Amending the soil is not recommended. Counterintuitively, backfilling with the same native soil you just dug up helps your plant develop a stronger root system.
When to Plant
The best time to plant big muhly is in the fall. This gives your grass three seasons to grow roots and get established before the following summer.
The second best time is in spring, the earlier the better. This still gives your plant time to get established before the intense heat of June arrives.
Fun Fact!
Big muhly seeds are so small it takes
2.5 million of them to make a pound.
How to Care for Big Muhly
Whether you’ve recently planted big muhly or have an existing plant in your yard, here’s how to take care of it to keep it healthy and looking its best.
How to Water New Plants
As a southwest native, big muhly needs very little water once established, but it does need regular watering after being planted.
Here is the recommended watering schedule for new ornamental grasses.
| Weeks 1 & 2 | Every 3 – 4 days |
| Weeks 3 & 4 | Every 6 – 7 days |
| Weeks 5 & 6 | Every 7 – 10 days |
| Weeks 7 & 8 | Every 10 – 14 days |
How to Water Established Plants
Once your big muhly is established, water it deeply every few weeks during the summer. These plants will brown out during the summer when they don’t get enough water. They are drought resistant but in their native habitat they are a riparian species, and so look their best with occasional watering during the summer.
Since plants go dormant in the winter, they only need water once a month, which is typically provided by winter rains.
Should You Fertilize?
There is no need to fertilize big muhly since it gets all the nutrients it needs from native soil.
Rake, Don’t Prune
It’s generally recommended that you prune ornamental grasses hard once in late winter or early spring. And while you can do that with big muhly, it’s not the best way to remove old growth. The Native Plant Society of Texas recommends that you rake this plant hard instead, since some plants struggle to rebound after a hard prune.
Big Muhly Cultivar
Muhlenbergia lindheimeri ‘Autumn Glow‘ is a cultivar that is more adaptable than the parent plant. It tolerates full sun to nearly full shade, and most soil types. It’s a good choice for retention basins or other areas that receive periodic flooding.
Plant Lover Facts
Big muhly (Muhlenbergia lindheimeri) has a few alternative common names including Lindheimer’s muhly grass, Lindheimer’s muhly, Lindheimer muhly, and blue muhly.
The genus, Muhlenbergia, was named after the German botanist Gotthilf Muhlenberg, who is credited with classifying and naming at least 150 plant species.
Muhlenbergia is a genus of 175 grasses, mostly native to the desert southwest. But only a handful are used as landscape plants.
The species was named after Ferdinand Jacob Lindheimer, a botanist who is known as the “father of Texas botany.”
Have you grown this plant?
Was it a “hit” or a “miss” in your garden?
Please share your experience in the comments below!
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for 15 years.
