Pampas Grass Care – How To Grow Pampas Grass
By: Nikki Tilley, Author of The Bulb-o-licious Garden
Most people are familiar with the large clumps of lush, grass-like foliage and creamy white feathery plumes of pampas grass (though pink varieties are available too). Pampas grass (Cortaderia) is an attractive ornamental grass that is popular in many landscapes. While they’re extremely easy to grow, however, it’s important to know what you’re getting into before planting pampas grass around the home. Don’t be so quick to plant it simply because it looks good. It’s actually a very fast grower and can become quite large, anywhere from 5 and 10 feet (1.5-3 m.) high and wide, and even invasive.
How to Grow Pampas Grass
Before growing pampas grass, be sure to put it somewhere in the landscape where it has plenty of room to grow, especially when planting more than one. When mass planting pampas grass, you’ll have to space them about 6 to 8 feet (2 m.) apart.
Pampas grass enjoys areas with full sun but will tolerate partial shade. It also tolerates a wide range of soil types but prefers moist, well-draining soil. Another plus side to growing pampas grass is its tolerance of drought, wind, and salt sprays—which is why you commonly see the plant along coastal regions.
The grass is hardy in USDA zones 7 through 11, but in well protected areas, it can even be grown in Zone 6. It’s not suited for cold regions unless grown in pots and brought indoors over winter and replanted outdoors in spring. Due to its large size, however, this isn’t really practical.
How to Care for Pampas Grass
Once established, pampas grass care is minimal, requiring little maintenance other than watering in extreme drought. It should also be pruned each year to the ground. This is usually performed in late winter or early spring. Due to the plant’s sharp foliage, the task of pruning should be done with great care using gloves and a long-sleeved shirt.
However, with appropriate measures taken (for clumps well away from homes and buildings), you can also burn the foliage down to the green growth without any harm to the plant.
While not required, pampas grass can be given a balanced fertilizer following pruning to help stimulate regrowth.
Propagating Pampas Grass
Pampas grass is usually propagated through division in spring. Pruned clumps can be sliced through with a shovel and replanted elsewhere. Normally, only female plants are propagated. Pampas grass bears male and female plumes on separate plants, with females being the most common among varieties grown. They are much showier then their male counterparts with fuller plumes (flowers) of silk-like hairs, of which the males do not have.
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Gardening 101: Pampas Grass
The majestic plumes of perennial pampas grass have inspired poets—and provoked the scorn of environmentalists. For good reason, in both cases.
First, what’s good about pampas grass? The poet Edna St. Vincent Millay bemoaned the cold, dark days of late autumn when the “feathered pampas-grass rides into the wind, like aged warriors westward, tragic, thinned of half their tribe.” In other words, when resilient pampas grass starts to look tired in a landscape, winter is upon us. In other seasons, 13-foot-high clumps wave buoyant snowy plumes and create as much visual interest as any small specimen tree. (One of our favorite examples of this is in magical English garden Saint Timothee.)
What are the drawbacks to pampas grass? The biggest negative: Pampas grass is invasive in some climates, notably on the US West Coast and in Australia and New Zealand, where it is a rampant weed and crowds out native species and tree seedlings. (This behavior does not occur in its native South American environments, where “Cortaderia selloana grows on river plains where part of the year the crown is under water while the rest of the year the plant is stressed by drought,” as Pacific Horticulture notes.)
Not all pampas grass is equally invasive, however. Read on to learn how to tell the difference between “bad” pampas grass and “safe” pampas grass before you plant it in a landscape:
Above: Pampas grass. Photograph by Tony Hisgett via Flickr.
One species of Cortaderia is much more invasive. If you happen to see pampas grass at a plant nursery, run—don’t walk—away from Cortaderia jubata, a weedy species that has none of the good looks of Cortaderia selloana. Jubata grass, which has “harsh, cutting leaves” also has “dun-colored plumes that look like old dishrags on sticks,” according to Pacific Horticulture writer John Madison, is Public Enemy No. 1 on the California Invasive Plant Council’s list.
The plant council also includes C. selloana on the invasive plants list. But experienced horticulturalists can contain it. “C. selloana is a dioecious plant, with male and female flowers on separate plants. The hairs on the ovary fluff up the plumes, making the female plants the desirable horticultural specimens. If only females are planted, there will be no pollen and no seed and the plumes will remain fluffed up for some time,” writes Madison. “Anyone buying a plant of pampas grass should ascertain beyond all doubt that it is a female plant of C. selloana.”
Above: Photograph by Jin Kemoole via Flickr.
On a lighter note, pampas grass also has gotten some recent bad press in the UK. Some homeowners have stopped planting it in their front gardens because its presence has become associated suburban sex scandals. How did pampas grass earn an X rating? “Plant sellers says sales have plummeted—in no small part due to the plant being regarded as a secret signal to passersby that its owners are happy to indulge in swinging,” notes the Telegraph. For the record, you can still find dwarf pampas grass among the offerings of more than 4,000 plants from Crocus plant nursery (£14.99 for a 2-liter pot of Cortaderia Selloana ‘Pumila’).
Above: Pampas grass steals the show at water’s edge. See more of this landscape in Magic in Maidenhead: An English Garden That Glows in the Winter. Photograph by Britt Willoughby Dyer.
Pampas Grass: A Field Guide
Statuesque pampas grass behaves well in its native South American climes and in such European countries as England and Ireland (but then, what plants don’t thrive in those spectacularly temperate conditions)? Few plants have as much theatrical presence as airy clumps of Cortaderia in a landscape. But in other parts of the world—notably Australia and the US—gardeners must be more judicious about their use of this perennial grass, which is invasive if special care is not taken.
First, know the difference between species. Showy Cortaderia selloana, 13 feet tall and sporting pure white plumes that look like feather dusters, can be controlled much more easily than dun-colored Cortaderia jubata, which has sharp, unfriendly foliage and a dangerous predilection for choking out nearby plants. A dwarf pampas grass cultivar, C. selloana ‘Pumila’, is a good compromise it will reach heights of 6 feet with showy plumes (but will not run rampant like a weed).
Mixed grasses make a lovely landscape. If you are looking for a tall, back-of-the-border perennial grass, consider Maiden Grass, particularly Miscanthus x giganteus (which will grow to heights of 12 feet and won’t behave like a thug). See dozens more of our favorite perennial grasses in our Grasses 101 guides.
It’s up to you whether you want to keep the leafage and blooms in winter or not, because it can either be trimmed and evened out, or simply kept as is.
But since Pampas grass can quickly turn invasive if nothing is done, here is our advice on trimming it:
- Cut back the plant to the shortest at the end of fall, when the blades of grass and flowers have dried up.
- Mulch the foot of the plant with dried leaves if the winter is very harsh in your area.
- In areas with mild climates, simply cut the grass back to 20 inches (50 cm), no need to protect the base of the grass shoots.
Although it may seem like a hands-off plant, some routine maintenance is necessary to keep it looking good and in good health. In late winter or early spring each year, prune the foliage back just above ground level. Be sure to protect yourself with long sleeves, gloves, and safety glasses for this project. Bundle the foliage together with twine, and use power hedge shears or a chainsaw to cut it off 10 to 12 inches above the ground.
After three or four growing seasons, the plant will have become quite large. So large, in fact, that you may notice while cutting it back that the interior is becoming hollow. The outside roots continue to grow outward, but the interior root crown is dying from a lack of sunlight. This is a good time to dig up the entire plant. Use a sharp garden spade to cut away the good parts into about four healthy divisions. Then remove the dead portion of the crown. Replace the original with one of the divisions. Plant the others elsewhere, share them with friends, or compost them.
How to Maintain Pampas Grass
Once you have established your plantation for this ornamental grass, you will need to care for and maintain it. Generally, it needs very little care.
- Protect it from Cold – In cooler areas, during the end of the growing season, wear your gloves and protective gear. It is the season of tying the leaves of the plant together! This will help protect the plant against shock that is caused by cold. If you live in areas that freeze, you might need to cover your pampas grass when the temperatures drop to below freezing point.
- Pampass Grass Pruning – Early spring, prune and burn the dead stalks of your plant to the ground. This will not damage the plant or its roots. The pruning of all the dead stalks makes way for fresh new growth. During pruning wear protective gear to avoid being badly cut when handling the grass. The leaves are blade-like, razor-sharp, and can easily inflict injury if you don’t protect yourself.
- Fertilizing the Pampas Grass – Pampas grass does very well with little or no fertilizer. You can choose to either use fertilizer or not. If you choose to use some, give it a bit of balanced fertilizer in the springtime right after pruning to stimulate the springtime growth.
- Propagating Pampas Grass – After pruning your ornamental grass, it’s time to separate and replant the huge chunks of grass growing together. Slice the roots into clumps with a sharp shovel. Dig up a shovel of roots and plant them in a new hole that has the same height and length of the root system. You can use your hands to separate the roots. Place some fertilized potting soil in the hole before planting the new grass. Water the grass well to reduce transplant shock. Soon you will have a whole new plant.