Ornamental grasses, which are perennial plants prized for their fine texture and movement, offer a dynamic element to any landscape. They provide year-round interest, often displaying striking foliage color and form long after flowering plants have faded. Successful placement requires aligning the plant’s needs with the specific conditions of a location. Understanding the environmental factors, the desired design function, and the long-term growth habits of these plants is necessary for achieving the best results in the garden.
Matching Environmental Needs to Location
The first step in determining where to plant an ornamental grass is a thorough assessment of the site’s existing environmental conditions. Sunlight exposure is a primary determinant of a grass’s health, color, and ability to produce feathery flower plumes. Most varieties thrive in full sun, requiring a minimum of six hours of direct sunlight daily to maintain vibrant foliage color and encourage robust flowering. Conversely, deep shade can lead to weak, floppy growth, though some types, such as Black Mondo Grass (Ophiopogon planiscapus) or Japanese Forest Grass, are adapted to handle less intense light.
Soil composition and drainage are equally important factors, as the majority of ornamental grasses will not tolerate perpetually wet feet. Poor drainage causes roots to sit in saturated conditions, often leading to root rot and plant failure. Soil must drain at a rate of approximately one inch per hour to be suitable for most grasses; if the site consists of heavy clay, incorporating organic matter like compost improves the percolation rate.
While many grasses are celebrated for their drought tolerance once established, water availability is still a consideration during the first growing season. Newly planted specimens require frequent watering, sometimes every other day for the first few weeks, to encourage deep root growth. After this establishment period, most mature grasses can rely solely on natural rainfall. However, supplemental watering every few weeks during extended dry spells prevents stress and foliage browning, particularly in varieties with dark-colored leaves.
Functional Placement in Garden Design
Beyond meeting the plant’s basic needs, the location should be chosen based on the functional role the grass will play within the overall garden scheme. Taller varieties, such as certain switchgrasses or Miscanthus, are frequently used to create naturalistic privacy screens or hedges along property lines. These vertical forms act as a soft, fast-growing barrier, providing seclusion without the imposing appearance of a solid fence. They should be positioned where their mature height will adequately block the view, often serving as the structural backdrop of a perennial border.
Shorter, clumping grasses are suited for defining the edges of walkways, patios, or garden beds. Compact varieties like Blue Fescue (Festuca glauca) or dwarf fountain grasses create a neat, mounding border that softens the transition between hard surfaces and planted areas. This placement helps to visually anchor the garden while the fine texture softens the impact of hardscaping, such as retaining walls and concrete edges.
Placing grasses as accent plants or focal points leverages their unique form and movement. A single, large specimen of an arching grass can be used in a prominent location, such as near a garden entrance or at the corner of a house. This solitary placement allows the plant’s full architectural shape and seasonal color changes to be appreciated, and they are also excellent choices for container gardening in smaller spaces.
The robust root systems of many ornamental grasses make them effective for stabilizing soil on hillsides and banks. Planting grasses on slopes prone to erosion helps bind soil particles together, reducing runoff and loss of topsoil. This functional placement utilizes the plant’s natural tenacity in challenging areas, making them ideal for filling in dry spots or rocky soil where maintenance is difficult.
Long-Term Considerations for Grass Selection and Spacing
Selecting the correct grass for a location involves planning for the future dimensions of the plant and its ability to survive the local climate. Hardiness zones dictate whether a specific grass will reliably return each year as a perennial or must be treated as a seasonal annual. Choosing a variety rated for the local winter temperatures ensures the plant will establish and provide its intended function for many years.
Proper spacing is a common oversight that impacts the long-term health and aesthetic of the planting. A general rule for many upright grasses is that the mature width will be approximately half of the mature height. Failing to account for this final size, such as giving a six-foot grass less than a three-foot diameter of space, results in overcrowding, restricts air circulation, and can lead to the center of the plant dying out.
A significant distinction for placement is the difference between clumping and running varieties, which relates directly to their growth habit. Clumping grasses grow in compact tufts that slowly increase in diameter, making them easy to manage in confined garden beds. Running grasses spread aggressively through underground stems called rhizomes or above-ground stolons, requiring a location where their lateral spread will not interfere with nearby plants, paving, or boundaries.