Pampas grass (Cortaderia selloana) is a magnificent ornamental grass prized for its striking, feather-like plumes that provide dramatic texture and height to a landscape. Native to South America, this perennial forms large, dense tussocks of foliage with flower stalks that bloom from late summer into winter. Cultivating this vigorous plant requires specific care practices focused on establishment, annual maintenance, and seasonal cutbacks.
Establishing Pampas Grass
Successful establishment begins with careful site selection, as pampas grass is long-lived and difficult to move once rooted. The plant demands a location that receives full sunlight for optimal growth and plume production, needing at least six hours of direct sun daily. While it tolerates a range of soil types, excellent drainage is required to prevent crown rot. Amend heavy clay soils with organic matter like compost or coarse sand.
Planting is best performed in the spring or early summer after the danger of frost has passed, or in the early fall. This timing allows the roots time to settle before winter. Dig a planting hole twice the width of the root ball but no deeper, ensuring the top of the root ball sits slightly above the surrounding soil level. Since mature plants can reach up to eight feet in height and width, space individual plants at least six to eight feet apart for proper air circulation.
Year-Round Routine Care
Once established, pampas grass becomes notably low-maintenance regarding its water and nutrient requirements. Newly planted grass needs deep, consistent watering during its first growing season to encourage a strong root system. This initial heavy irrigation helps the plant acclimate to its new environment.
After the first year, pampas grass is highly drought-tolerant and rarely requires supplemental watering, relying on natural rainfall. Overwatering is a common mistake that can lead to disease, so only irrigate during periods of prolonged and extreme drought. Fertilization is minimal; established plants typically do not need it. However, a light application of a balanced fertilizer, such as a 10-10-10 formula, in early spring can boost a sluggish plant or encourage robust plume development.
Essential Seasonal Pruning
Pruning is the most important annual maintenance task and must be timed correctly to avoid damaging new growth. The ideal time for this aggressive cutback is late winter or very early spring, just before new shoots emerge from the base. Waiting until this period allows the old foliage to protect the plant’s crown from harsh winter cold and provides visual interest during the dormant season.
Before beginning, gather the entire clump of dry foliage and tie it tightly together with rope or twine; this makes the subsequent removal of the bulky material easier. Cut the plant back aggressively to a height of six to twelve inches above the ground, completely removing the previous year’s growth. This pruning clears out dead material, promotes healthy air circulation, and makes way for fresh foliage and plumes.
A serious safety precaution must be observed during this process due to the sharp, serrated edges of the leaves, which can inflict painful cuts. Wear heavy-duty leather gloves, long sleeves, and protective eyewear to shield the hands, arms, and face from the foliage. Using sharp loppers, hedge shears, or even a power trimmer will make the task less strenuous.
Preparing for Winter and Managing Growth
In colder climates, preparation helps ensure the pampas grass survives the winter without crown damage. Leaving the dry foliage intact serves as a natural insulation layer, protecting the sensitive growing point from freezing temperatures. In regions with heavy snow or ice, tying the foliage together in a bundle before the first hard frost prevents the plant from splaying open and suffering damage.
While pampas grass is resilient, the center of the clump can eventually die out, reducing the plant’s vigor and appearance. To manage size and rejuvenate an aging plant, division is necessary every three to five years. This task is arduous due to the dense, tough root system, often requiring specialized tools like a sharp spade, a heavy-duty saw, or an axe to cut through the woody mass.
The best time to divide pampas grass is in the spring before the new season’s growth begins, allowing the divisions the entire growing season to establish new roots. Dig up the entire clump and use a sharp tool to divide it into smaller, viable sections. Ensure each piece retains a portion of the roots and some new growth buds. Replant the healthy sections immediately in well-prepared soil, discarding the dead, woody center of the original plant.