Miscanthus nepalensis

Ornamental grasses - Grow Guide

Find out all you need to know about growing ornamental grasses, including planting, dividing and cutting back in spring.

Ornamental grasses have seen a huge increase in popularity over the last decade. They’re highly valued as low-maintenance plants and many grow well in poor soil. They provide interest for most, if not all of the year. Grasses are hardy, resistant to pests and diseases and are quick growing.

Discover five combinations of grasses and flowers.

There is an ornamental grass for nearly every garden situation. Plants can be evergreen or deciduous and range in height from 30cm to about 4m. They are often used to create a breathing space in busy flower borders, for container displays or as specimen plants.

Although grown primarily for their foliage, their flowers can be spectacular. Why not grow a grass native to the UK, such as Molinia caerulea?

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Planting position

With so many varied ornamental grasses to choose from there is a plant for every position. For a really hot, dry spot grow Calamagrostis x acutiflora ‘Karl Foerster’ or a festuca. For a shady and water retentive soil choose a milium and acorus. For a coastal garden cortaderia is ideal and for grasses to grow as a marginal by the pond look to juncus or Carex pendula.

Before buying a plant seek advice from a specialist grower, as there are so many wonderful grasses to choose from.

Taller grasses will appreciate a sheltered position as this will prevent their long flower spikes from being damaged by the wind.
If planting in a container use a John Innes no 2 compost. 

Planting technique

Grasses can be planted all year round but ideally plant in spring or autumn. For those grasses that enjoy a dry soil improve the drainage by digging in horticultural grit before planting.

Dig a planting hole, place the plant in the hole so it is planted at the same depth as it was in the original pot, backfill and firm in. Water plants in well. Grasses do not need regular feeding.

If you are buying very tall grasses and the long flower stems are broken or messy at planting time, simply cut the damaged stems right back. 

Propagation

Ornamental grasses can be divided in early spring. Very mature clumps are often tricky to lift, so have a friend on hand to help. In order to divide large clumps push two garden forks into the crown of the plant back to back and pull the handles down.

Some grasses, such as Nassella tenuissima, self-seed readily. Look out for the seedlings and pot them on. 

Troubleshooting

Grasses are trouble-free and don’t attract pests or diseases. 

Care

Ornamental grasses offer months of interest. Leave them uncut through the winter and let the frost decorate them. Deciduous types should be cut back in early March. Evergreen types are not cut back until April through until July. Evergreen grasses shouldn't be cut right back - a light trim is sometimes all that is necessary. Tidy up all evergreens by pulling old stems out of the plant. Wear gloves when ‘combing’ grasses as some grasses are sharp. 

Spade

Plant grasses in drifts

Grasses have risen in popularity thanks to the interest in prairie-style plantings. Grasses and perennials are planted together in drifts to create a natural look that offers movement and colour. 

Pennisetum villosum
Pennisetum villosum

Ornamental grasses to try

  • Micanthus ‘Flamingo’ – a popular, deciduous grass with late summer, pink flower plumes. Ideal for a sunny spot. Reaches 2m
  • Acorus variegatus – an attractive, evergreen, variegated grass. Grows well in average to moist soil in sun or part shade. Height 25cm
  • Briza ‘Golden Bee’ – stunning flower heads in summer. A golden, semi-evergreen grass that thrives in sun or light shade. Reaches a height of 50cm
  • Calamagrostis x acutiflora ‘Karl Foerster’ – a striking deciduous grass with a wonderful architectural habit. Plentiful flower stems that stand up well without support. Ideal for a sunny spot. Height 1.8m
  • Stipa tenuissima (now called Nassella tenuissima) – a popular evergreen grass with soft, fine foliage and flowers. Moves well in the wind. Enjoys a sunny, well-drained spot. Height 50cm. Self-seeds readily
  • Pennisetum villosum (pictured) - a deciduous perennial grass with bunny-tail like flowers that you can't resist stroking. 60cm

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