Planting ornamental grasses

As a group, grasses are the most versatile of plants. Species can be found that will thrive in wet or dry locations, in full sun or dense shade, in acidic or alkaline soils. These steps will walk you through choosing, buying and planting the best ornamental grass for your lawn.

Attractive as their foliage is, most ornamental grasses are grown for their interesting, and usually decorative, flower spikes and the resulting seed heads. Many are excellent ground covers, some make good container specimens, while others add stature and height to a mixed border where their stately plumes bend and sway in the slightest breeze.

Whether it is the white woolly stems of cotton grass (Eriophorum), only 45 centimetres (18 inches) tall, or the towering three-metre (10-foot) spikes of pampas grass (Cortaderia), it is the seed heads that are important.

As well as the tall plumes of seed heads that are so prominent in the fall garden, many grasses have interesting pendulous seeds. Wild oats (Chasmanthium) have diamond-shaped, flattened seed heads in hanging clusters, while those of Job's tears (Coix) are hard enough to string and use as beads. All grasses spread slowly and gradually increase in size, but some are more aggressive and spread rapidly.

In most catalogues, grasses are listed as clumping or running.

• Clumping grasses stay in one place and will not suddenly appear some distance away; ones that increase very slowly are referred to as bunch grasses.
• Running grasses spread rapidly by underground roots (stolons) or stems (rhizomes) and can become a major problem if left unchecked. They make excellent ground covers and are an ideal choice for planting on a bank to stabilize the soil.

Most of the commonly grown species are very adaptable and will grow in soils ranging from heavy clay to fast-draining and infertile sands, although their performance will differ greatly. Winter survival in cold climates may depend on good drainage, and species like blue fescue (Festuca glauca) may die if planted in poorly drained soil. Grasses that spread underground can be overly aggressive in a rich soil, but quite manageable in a poor one. Most soils benefit from the addition of compost to increase their moisture-holding capacity, but the use of nutrient-rich manures should be avoided.

The most important consideration in preparing a soil for grasses is the removal of perennial weeds, especially perennial grasses, such as couch grass (also known as twitch). This grass spreads by underground stolons, which can grow into the middle of clump-forming ornamental grasses and be almost impossible to remove.

Potted plants can be planted any time the soil is not frozen, but early spring is best. Avoid buying plants that are in full growth - they do not transplant as well and have probably become root-bound. Small potted plants are preferable to large ones in big containers. They establish better and often outgrow a larger plant.

1.  Stand potted grasses in a container of water for an hour or two before planting to soak their root balls all the way through.
2. Dig a hole large enough to take the root ball and work a little bone meal into the base of the hole to stimulate root production.
3. Fill in around the roots and firm the soil in place with your fingers to avoid air pockets.
4. Leave the top of the root ball just slightly below soil level so that the plant sits in a slight depression to retain water.
5. Give the area a good soaking and be prepared to water frequently for the first few weeks. Grasses are very drought-tolerant but they need a little pampering at first.