Ornamental grasses are a versatile group of hardy plants that can really bring drama to any garden. Whether you want a small one for a pot, or to weave texture through your borders, their clumps of long, feathery leaves (and often flower-heads) won’t disappoint. September is a great time to think about where you would plant one (or two…).
Growing grasses in our gardens has become popular in the UK over the last 10 or 15 years for several reasons, we think. First, undoubtedly the trend for ‘prairie planting’ has really caught on. Grasses are well-suited to providing the natural swathes of foliage that this style requires. Secondly, people are realising that grasses are generally fairly low maintenance and many do really well in pots or containers.
Ornamental grasses can also quickly provide height and movement in a garden, often all year round, and the majority are perennial so will keep doing that year after year. Finally, a plus for us is that many grasses and their seeds provide shelter and food for the gardener’s friends, pollinating insects. So why wouldn’t you choose to have one or two well-chosen grasses in your plot?
The image on the left perfectly illustrates the flowing movement typical of prairie-style planting, seen at Dove Cottage via the RHS website.
September is a great time to plant grasses, particularly those which originate from cooler climates. These include the Stipas, Deschampsia and Festuca. (If your grasses come from warmer climes, you can still plant in September as long as the soil still has some warmth in it. If there have been early frosts, though, leave Pennisetum, Panicum and Miscanthus varieties until the late spring.)
Most grasses prefer fertile soil and full sun; they may fail to thrive in shade. They also tend not to like extremes of soil, either too dry or waterlogged. That said, there are always exceptions (see our ‘pick of the grasses’ below for some of them). It’s best to read the plant label or chat with one of our plant experts in centre to be sure you are picking a plant that will flourish in the spot where you want to plant it.
Plant your new grass as soon as you get it home from the garden centre; if you can’t do that, leave it in a sunny but sheltered spot outside and keep it well watered until you do have time to plant it.
When you’re ready, start by preparing the soil. Dig (or double dig if you have the space) through the soil and remove any weeds. Make a hole about half as big again as the pot the grass came in. Loosen the soil at the bottom of your hole too, adding grit for drainage or home-made compost for nutrients if you feel you need to.
Next, knock your plant out of its pot and check the roots. If they are circling round the pot, break some of the roots. Don’t worry if they break a little, this helps to stimulate the plant into new growth so will encourage the roots to explore your soil.
Site the grass in the hole and check that the base of the plant will be level with the surrounding soil. Too low or too proud could cause shoots to rot or dry out. Then check the positioning of the grass; move it around a bit to check you have its best side and that it’s sitting upright in the hole.
When you’re happy, you can now firm the soil back around the plant to secure it. Use your heel to press down well, removing air pockets and to leave a small divot around the plant to help collect water. Finally, water in well, regardless of what the weather is doing!
f you are trying to create big impact, it can be tempting to plant grasses too close together. In the long run, you are just hampering the plants, as they will all be competing for light and nutrients. Check the plant label to see how big the clump is likely to grow to ensure you give it enough room.
Find our blog about caring for ornamental grasses here for further advice.
Stipa gigantea – best for height and impact!
If you’re looking for something dramatic, Stipa gigantea earns it name for good reason: it can mature to heights of up to 2.5 metres, given the space to do so. It’s loved by insects and is fairly drought-tolerant, but will prefer a well-drained, sunny spot.
Anemanthele lessoniana – best for shadier spots
Anemanthele is one of few grasses that will tolerate a partially shaded site. Also sometimes known as Pheasant grass or New Zealand wind grass, its elegant, narrow leaves will show tinges of red and orange in late summer and autumn. Again, it’s a great plant for pollinators and can grow up to 1 metre in height.
Hakonechloa macra ‘Alboaurea’ – best compact grass
If you’re looking for the movement of grass but in a smaller space, Hakonechloa could be a good choice. When mature, it rarely gets to more than 50cm (20 inches) tall or wide. It has all the insect-attracting benefits of other grasses and its pale creamy-white leaves will often turn reddish in autumn.
Acorus gramineus ‘Ogon’ – best for wetter conditions
Also known as Sweet Flag, this is a semi-evergreen grass which provides vibrant colour for much of the year. Unlike many other grasses, it actually prefers wetter soil types and can cope with poor drainage, making it a great pond-edge grass. It also tends to stay fairly short and compact.
Miscanthus ‘Gold Bar’ – best for colour
Many grasses of the Miscanthus family have interesting colours but ‘Gold Bar’ is one of our favourites because of its unusual markings. Its narrow, green leaves have cream horizontal stripes! Like other grasses, it’s great for pollinators and prefers a sunny position. It can grow up to 1.5 metres high and wide if given the space.