Ornamental grasses have experienced a huge surge in popularity over the past decade. They are highly valued as low-maintenance plants, and many grow well even in poor soils. They are interesting almost all year round. Grasses are hardy, resistant to pests and diseases, and grow quickly. There is an ornamental grass for almost any garden situation. Plants can be annuals or perennials, evergreen or deciduous, and can reach heights from 30 inches to about 4 feet. They are often used to create a breathing space in busy flower borders, for containers or as specimen plants. How to plant grasses and what to consider, read on!
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Types of grasses
Ornamental grasses include both true grasses and grass-like plants such as sedges, which are used for similar purposes in the garden. Most ornamental grasses are perennials that live for two or more years. Annual plants only last one growing season due to their natural growth habit or they are not hardy in our climate.
Plants grow either clumpy or spreading. Spreading grasses spread rapidly by above or below ground stems. Care should be taken when planting spreading grasses as they can crowd out unwanted plantings. Clump or bunch grasses grow in a clump that gradually increases in diameter.
Planting grasses: How to do it right
When to plant grasses. Plant ornamental grasses in the spring or fall. There are many species, all with different site requirements – some do best in moist but well-drained soil, while others prefer dry or water-holding soil. Most plants do best in sun, but some tolerate shade. Be sure to grow the right grass for the right location.
Dig a planting hole, place the plant in the hole so that it is at the same depth as in the original pot, fill it in and tighten. Water the plants well. Plants do not need to be fed regularly. Deciduous grasses should be cut back in early March. Tidy up any evergreen grasses by pulling the old shoots from the plant. Wear gloves when “combing” grasses as some grasses are sharp.
Tips for caring for the plants
- Watering: once grasses are established, moisture needs vary depending on grass species, soil type, temperature and other factors. Most ornamental grasses grow best when they receive at least one inch of water per week through rain or irrigation. Drip irrigation is an excellent method for watering grasses. It conserves water by delivering it directly to the roots and reduces the risk of foliar diseases. For plants that do best in dry soil, improve drainage by incorporating horticultural grit before planting.
- Fertilization: Most ornamental grasses require very little fertilizer. It is best to base fertilization on the results of a soil test. Too much nitrogen in the soil can cause disease susceptibility, vigorous growth, and weak stems that cause the plant to fall over.
- Cut back: Cut back plants before the new season begins. Because many grasses are attractive in the winter garden, they are usually cut back in late winter or early spring. Cut stems to a few inches above the ground for best appearance. There are several ways to cut back grasses. They can be cut back by hand, with pruning shears or hedge trimmers, electric hedge trimmers, or a weed trimmer with a clearing blade. Some evergreen grasses, such as sedges (Carex) or flag weed (Acorus), do not recover quickly from pruning. Comb the foliage of these plants in spring with gloved hands to remove old leaves.
- Divide: Most plants should be divided every 3 to 4 years. If ornamental grasses are not divided, they will thin or die in the center over time. It is best to divide grasses while they are still a manageable size. Overgrown grasses are very difficult to dig up and divide. Dig up warm-season grasses in early spring, just before new growth begins. Divide cool-season plants in early fall. Most grasses have tough, strong root systems and may need to be divided with a shovel, saw or ax. Hose down the soil to make it easier to work the roots. Then sever the vigorous growth at the outer edges of the clump and replant. Replant in a timely manner and do not allow the roots to dry out.
How to plant grasses from seedlings.
You can also grow ornamental grasses from seed. Ornamental grasses are expensive to buy. So why not try growing them from seed? Some grasses, like Nassella tenuissima, self-seed easily. Look for the seedlings and plant them. Here’s how easy it is to plant grasses.
Plant grasses in a pot
- Find a suitable shallow container with good drainage.
- Cover the bottom of the container with about half an inch to an inch of gravel or small pebbles to help with water drainage.
- Sprinkle the soil with the grass seeds.
- Use your spray bottle to lightly water the seeds until the soil is moist.
Great varieties to plant
- Micanthus ‘Flamingo’ – a popular deciduous grass with late summer pink flower plumes. Ideal for a sunny spot. Reaches 2 m.
- Acorus variegatus – an attractive evergreen variegated grass. Grows well in medium to moist soil in sun or partial shade. Height 25 cm.
- Briza ‘Golden Bee’ – stunning flower heads in summer. A golden, semi-evergreen grass that thrives in sun or partial shade. Reaches a height of 50 cm.
- Calamagrostis x acutiflora ‘Karl Foerster’ – a showy deciduous grass with a wonderful architectural habit. Lush flowering stems that hold up well without support. Ideal for a sunny spot. Height 1.8 m.
- Stipa tenuissima (now Nassella tenuissima) – a popular evergreen grass with soft, fine foliage and flowers. Moves well in the wind. Prefers a sunny, well-drained spot. Height 50 cm. Self-seeds easily.
- Pennisetum villosum – a deciduous perennial grass with rabbit tail-like flowers that you just have to pet. Height 60 cm.