Planting pampas grass is an easy way to add drama to your landscape. The tall stalks tend to grow together, and the fluffy fronds offer an attractive alternative to privacy hedges or fences. It also spreads easily, making it an economical choice for border plantings. Like many types of ornamental grass, it is low maintenance and remarkably unbothered by most pests and diseases.
If you are planting a row or other grouping, leave at least 6 feet between each pampas grass plant. To encourage rapid growth, dig a hole large enough that you can gently separate the root ball, and the roots can spread out. Work some organic material, such as compost or peat moss, into the soil from the hole. Adding organic matter loosens the soil and helps the plant's roots expand. Place it back around the root ball after planting.
Pampas grass prefers well-drained, loamy soil, though it does tolerate other types and can do well in less-than-ideal planting conditions. If your soil is naturally compacted and holds water or is poor quality and dry, use organic matter to improve drainage and add nutrients. Pampas grass is not particular about whether the soil is acidic or alkaline.
Pampas grass does best when planted in full sun, which means at least 6 hours of sunlight daily. It will tolerate partial shade but will not thrive. This grass originated in South America and prefers warmer climates. It is hardy to USDA zone 7 and can survive in zone 6 if you provide winter protection.
When pampas grass is young, it needs supplemental water — plan to water it every day for several weeks after planting. If it seems to be flourishing after this point, water twice a week. Continue this through its first year. The following growing season, you shouldn't need to water it at all unless conditions are particularly dry.
Though pampas grass is remarkably resistant to most pests and diseases, it is not completely safe. Aphids feed on the sap of many types of garden plants, including this one. Left unchecked, they can eventually kill the grass. Look for aphids by examining the underside of the grass blades. If you notice the leaves turning yellow, the grass may have a mite infestation. These pests are too small to see with the naked eye, but their damage is apparent. They feed by sucking juices from the plant. Insecticidal soap spray will take care of both aphids and mites.
Few diseases plague pampas grass. Powdery mildew causes problems for many types of plants and grasses. In the early stages, the leaves look like they are covered in cobwebs. As the fungus progresses, the leaves look dusted with flour. Pampas grass, when affected by powdery mildew, will lose its leaves. This affliction is most likely to take hold of grasses planted in partial shade or in areas with high humidity.
While pampas grass tolerates a range of soil conditions, it does best in areas with rich soil. If your garden lacks nutrients, regular applications of fertilizer or top dressing organic matter are beneficial. Pruning ensures you preserve the visual impact of this grass. Leave the growth in place over the winter months. After the danger of frost has passed, prune the stalks, leaving about 6 to 8 inches of old-growth. In warmer climates, the grass may not fall dormant at all. In these situations, all you need to do is trim the grass in late spring.
Pampas grass is divided to create additional plants, and this should be done in the spring. After pruning the grass, dig it up. Use a shovel to divide the clump in two. Return one half to the existing hole, and plant the other elsewhere. Identifying the male and female pampas grass allows you to propagate the more showy female, which blooms with full plumes of silky hair, creating an impressive show late in the summer.
Pampas grass is a showy and easy-to-grow plant. It is useful as a background plant in the garden or as a stand-alone feature in the landscape. Its late-summer plumes are popular additions to cut-flower arrangements. As attractive and beneficial as the grass is, it also has its drawbacks. In the right growing conditions it spreads aggressively, and some states consider it an invasive species. For example, it grows wild across California where it acts as fuel for wildfires while pushing out native species.