How to Grow and Care for Feather Reed Grass

Unlike many other ornamental grasses that tend to flop after they bloom, feather reed grass looks tidy and upright all year round. It grows in dense clumps of erect, narrow, green leaves that can reach around 3 feet long. Pinkish-purple, feathery flower spikes rise a couple of feet above the leaves in the summertime and gradually turn to tan or golden seeds, which can last into winter. The ornamental grass has a moderate growth rate and can be planted in the spring or fall.

Feather Reed Grass Care

Feather reed grass (Calamagrostis x acutiflora) is a popular perennial ornamental grass that comes from a hybrid cross between Calamagrostis arundinacea and Calamagrostis epigejos. Plant the feather reed grass root ball in the ground or a container at the same depth it was growing in its original container. Once established, this ornamental grass is fairly low maintenance. Regular maintenance will primarily be watering when the soil begins to dry out. Plan to cut the grass to the ground as part of your garden clean-up after winter. Feed annually, if your soil is poor.

Light

Feather reed grass grows best in full sun, meaning at least six hours of direct sunlight on most days. However, it does appreciate some shade from the harsh afternoon sun, especially in the warmer parts of its growing zones. But if it gets too much shade, it won’t flower as profusely, the leaves can get floppy, and the plant overall will be on the smaller side.

Soil

The grass tolerates a wide range of soil types. While rich, consistently moist, well-draining soil is best, it can tolerate heavy clay soil and wet areas of the landscape such as on the bank of a pond. 

Water

Feather reed grass has moderate water needs. So water it, but not too deeply, whenever the soil feels dry about an inch or two down. Watering once or twice a week will suffice, but water a bit more in extreme heat. Mature ornamental grasses do have some drought tolerance, but soil that is too dry will result in a plant that doesn’t reach its full growth potential.

Temperature and Humidity

The plant is regarded as a cool-season grass and doesn't care for intense heat. It should be planted when the temperature is below 75 degrees Fahrenheit, so it has time to establish a root system to take in moisture before the hot weather arrives. Feather reed grass can survive temperatures below freezing. However, in the northern parts of its growing zones, it can be helpful to put a layer of mulch over the plant to insulate it over the winter. Humidity typically isn’t an issue for feather reed grass, as long as there is good air circulation around the plant.

Fertilizer

Feather reed grass typically doesn’t require any supplemental fertilizer. But organic mulch and compost mixed into the soil can be beneficial for added nutrients. If you have poor soil, apply a balanced all-purpose plant food in the spring following label instructions. 

Types of Feather Reed Grass

There are a few popular varieties of feather reed grass:

• Calamagrostis x acutiflora 'Karl Foerster' is known for its neat vertical growth habit and pinkish-purple to reddish-bronze flower spikes.
• Calamagrostis x acutiflora 'Overdam' has white variegated leaves and white flowers, and it grows 2 to 3 feet tall.
• Calamagrostis x acutiflora 'Avalanche' has yellow variegated leaves and golden-brown flowers and also grows 2 to 3 feet tall.
  

Pruning

Since this grass still looks neat into winter and can provide interest with the seed heads, most growers wait until late winter or early spring to cut their feather reed grass to the ground. Shear it back just before new growth appears, so you don’t accidentally prune any new foliage. Use sterilized pruning shears or a hedge trimmer to cut the previous season’s growth to a few inches above the soil line.

Propagating Feather Reed Grass

Feather reed grass is usually not grown or propagated from its seeds. Because the plant is a hybrid, the seeds are sterile and they won't germinate. Sterile seeds also mean that you won’t have problems with your feather reed grass spreading invasively.

While feather reed grass won’t spread uncontrollably in the landscape, a clump will continue to get larger through the rhizomes that spread underground. The clump will need to be divided once it’s so large that sunlight and airflow won’t reach its center. Every three to five years in the spring before new growth appears, dig up the clump and gently pull it apart keeping as many roots intact as possible. Replant your divided clumps wherever you’d like.

Potting and Repotting Feather Reed Grass

Feather reed grass is a good ornamental grass for containers, and it can easily become a focal point on a patio or deck that is protected from the harsh sun. Regardless of whether the pot is glazed or unglazed, make sure the soil is well-draining and there are adequate drainage holes in the container. Make sure the pot is wide and deep enough for the root system and to accommodate a few years of growth before the need to repot a large plant.

Common Pests and Plant Diseases

Feather reed grass rarely has issues with pests or diseases. You may encounter aphids or mites, which are easily eliminated with insecticidal soap.

Watch out for fungal rust, which appears as discoloration on the foliage and can arise from long rainy spells. A fungicide can be helpful, but prevention by ensuring good air circulation around the grass is key.

Common Problems With Feather Reed Grass

Although feather reed grass is one of the easiest ornamental grasses to grow and maintain, there could be a couple of issues to watch for. Here are two problems you may encounter.

Browning Tips

If the tips of your feather reed grass turn brown, the plant may be underwatered or overfertilized. It is likely not overwatered as this type of grass usually doesn't mind boggy soil.

No Plumes

If your feather reed grass is not growing gorgeous plumes, it's not getting enough sunlight. Another reason for grass without plumes may be because the soil has too much nitrogen. Amend the soil with high phosphorus fertilizer or bone meal.