How to Identify and Remove Purple Pampas Grass

Purple pampas grass is a tall, graceful tufted perennial that can add some dramatic form and even privacy to the garden landscape. Introduced from South America as an ornamental and sculptural specimen plant, you should think twice before planting any variety of pampas grass because it reseeds itself prolifically and it is highly invasive. It will eventually overtake an entire garden bed, crowding out other plants and creating hard-to-remove root systems. In colder climates where purple pampas grass won't survive the winter, it can be grown as an annual. However, because the grass reaches reproductive maturity in its first year, growing it as an annual, even in a container, does not resolve the issue of it spreading aggressively from seed.

Invasiveness of Purple Pampas Grass

Purple pampas grass is a tough plant. It isn't very fussy about soil, it is fairly tolerant to drought, frost, intense sunlight, and salt (unlike other grasses). Also, it is mostly immune to pests or diseases. All of these factors enable the plant to establish itself where other plants may struggle, eventually taking over entire habitats. Purple pampas grass can grow in many different habitats and is particularly threatening to coastal habitats and dunes where it can eradicate endangered plant species. It also grows on roadsides, grasslands, and disturbed areas.

Each plant produces thousands of seeds per year that are dispersed by wind, water, animals, and humans, especially when the inflorescence is used in dried flower arrangements. Pampas grass not only affects biodiversity by outcompeting other plants, it also poses a physical hazard for birds, other wildlife, and humans due to its sharp leaf blades.

What Does Purple Pampas Grass Look Like

Purple pampas grass is a large, tufted, perennial grass. Its leaves are basal and spreading further up, bright green in color, and sharply serrated.

Pampas grass blooms in the late summer or early fall. The feathery plumes rise above the tufts. Their color varies; some cultivars have pinkish-white plumes, while others have silvery-white plumes. The color of the plumes changes as the season progresses. Purple plumes fade to pink or creamy-white. There are also pampas grass cultivars with variegated foliage and dwarf cultivars.

Pampas grass has male and female flowers on separate plants. Because female plants are the ones with the showier, large plumes, and the tiny flowers covered with silky hairs, plants sold in the nursery trade are always female. However, when pampas grass spreads from seed, the plants can be either female or male. The male flowers are smaller and don't have any silky hair on the plumes.

How to Get Rid of Purple Pampas Grass

The earlier you remove pampas grass, the better, as the mature plants have tough roots that are difficult to eradicate.

Young small plants can be simply hand-pulled. If the grass is larger, cut it down to the ground and dig the clump out using a shovel. For grasses that are very large and where you cannot dig out the entire root system, additional treatment with a broad-spectrum herbicide may be required to prevent it from regrowing. Remove as much of the grass as you can, then keep an eye on it and spray it with herbicide as it starts to regrow. If it keeps growing, repeat the treatment a few weeks later.

When handling purple pampas grass, always wear protective gear, including gloves, eye protection, and long pants and sleeves, as the blades of grass are very sharp.

How to Prevent Purple Pampas Grass from Spreading

If the infestation is so large that you cannot remove all the plants with their roots, at least make sure to cut the grass back early in the season so it won't send out plumes with flowers and cannot reseed itself.

If the grass already has plumes, in the late summer or early fall, do not throw them on the compost but dispose of them in the trash to prevent the seeds from dispersing.