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The best ornamental grasses and how to grow them
Deciduous grasses have long-lasting architectural seedheads that will add structure and interest to your garden. Discover our best varieties and tips for how to grow them
Ornamental grasses are perfect for adding structural interest to borders with their flowing foliage and attractive flowers. They last long into winter, too. There are hundreds of varieties, but the most popular are those with prominent seedheads and interesting foliage.
Which? Gardening magazine grew some of the most attractive varieties to see which would give the best and longest-lasting display.
Key facts
Plant type - Perennial
Position -Full sun
Soil -Well-drained, moist, no too wet
How to grow ornamental grasses: month by month
January
February
March
April
May
June
CUT BACK
CUT BACK/DIVIDE/PLANT
CUT BACK/DIVIDE/PLANT
FLOWERING
July
August
September
October
November
December
FLOWERING
FLOWERING
FLOWERING
FLOWERING
Growing ornamental grasses
Planting
Plant in spring or autumn in sun or light shade. Choose a bed with well-drained soil that doesn’t become too wet in winter.
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The more stars the better. OVERALL RATING Ignores price and is based on impact of display 20%; autumn colour/seedheads 20%; shape/habit 20%; peak flowering duration 10%; flowering impact 10%; weather resistance 10%; flowering duration 5% and pest and disease resistance 5%
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How we test ornamental grasses
We chose 22 widely available varieties, including some that hold an RHS Award of Garden Merit, concentrating on those with coloured foliage, prominent flowers and autumn colour.
We planted them in a sunny bed at our Capel Manor Gardens trial site in north London. We grew 17 varieties in a sunny bed at Greenbank Garden, Glasgow, removing five from the original list we knew wouldn’t thrive in wetter soil.
We grew them for two years, recording weekly when they were flowering. We assessed plants for the attractiveness of the flowers and foliage, autumn colour, whether they withstood rain and wind, and how well the seedheads lasted through the winter. All our Best Buys did well at both trial sites.
Caring for your plants
Ensure that plants don’t dry out in hot weather, but take care not to overwater. Leave the flower stems over winter as they look great in low sun and frost, and provide food for birds.
Comb out dead leaves if grasses need a tidy. Wear gloves as many grasses have sharp-edged foliage.
Cut back to the ground in late February to late March. Chopped up stems can be left on the soil around plants as a mulch.
Divide large, old clumps in spring. Dig up the plant and split it with two forks or a spade. Replant one section in the previous position and put the other section somewhere else in the garden.
Problems
Grasses suffer very few problems.
Rust
This is a fungal disease causing orange patches on leaves. Minimise the risk by avoiding overcrowding to allow better air circulation around plants.
Lack of flowers can be caused by insufficient sunlight or overfeeding.