Ornamental grasses: selection

The variations in colour and texture of ornamental grasses provide structure, movement and interest in planting schemes, even in the dead of winter. Usually partnered with late summer perennials, grasses provide a long season of interest.

Grasses at Knoll Gardens Dorset

Introduction

Ornamental grasses are adaptable, reliable plants, easily cultivated in sun or shade with some thriving in both. Although ideally well-drained soils suit these plants, some will grow happily in moist or wet soils.

To learn more about cultivating ornamental grasses see our pages;

Ornamental grasses
Ornamental grasses: cutting back
Ornamental grasses: dividing

Practical considerations

Before choosing an ornamental grass it is important to understand your garden. Here are a few points to consider before making your choice:

  • A suitable soil test (RHS Soil Analysis Service) will help identify the soil texture and acidity or alkalinity which will influence the range of suitable grasses. Acid-loving (lime-hating) or ericaceous grasses grow best in a pH range of 4-6 and ideally pH 5-5.5
  • Note the number of hours of sunshine the position receives as the seasons change
  • Consider the ultimate height and spread of the grass as well as the rate of growth
  • Assess the microclimate of your garden and choose suitable grasses

Suitable plants

This section consists of usually widely available ornamental grasses for general garden use. Many of the cultivars listed have received the RHS Award of Garden Merit (AGM) and can be located for purchase on RHS Find a Plant.
Plants are grouped by season of interest, foliage colour, screening and for specific growing conditions.

Residents in milder coastal areas, milder counties and owners of warm, sheltered sunny walls might add considerably to these lists, e.g. Restio paniculatus, R. tetraphyllus (m).

Key
a = neutral to acid soils
c = suits containers
e = evergreen
f = good for cutting and drying
v = variegated foliage

Season of interest

Spring

In spring many grasses start to show new growth and a few will begin to produce flowers. Ones with particular spring interest include:

Calamagrostis × acutiflora 'Overdam' (v) (feather reed grass) bright-green and white striped leaves. Height 1.2m (4ft)
Imperata cylindrical 'Rubra' (c) mid-green leaves to 50cm (20ins) long turn quickly to crimson-red in spring
Millium effusum 'Aureum' AGM (Bowles' golden grass) (c) semi-evergreen rich golden-yellow leaves, especially in spring. Height 60cm (2ft)
Pennisetum thunbergii 'Red Buttons' compact clumps of narrow, grassy leaves and bright-red button-like flowers on tall stems. Height 75cm (30ins) or more
Stipa gigantea 'Gold Fontaene' golden-green leaves and large golden-brown flowerheads to 2m (6½ft) or more

Summer

Many grasses produce mounds of foliage by summer and are beginning to flower in profusion, including:

Calamagrostis brachytricha AGM (Korean feather reed grass) hairy, dark green leaves and feathery flower panicles. Height 1.2m (4ft)
Miscanthus nepalensis airy metallic-gold flower tassels from midsummer onwards, above mounds of dark green foliage. Height to 1.5m (5ft)
Molinia caerulea subsp. caerulea 'Edith Dudzus' (purple moor grass) mid-green leaves have purple bases and dark purple spikelets on deep purple-black arching stems and M. caerulea subsp. caerulea 'Moorhexe' AGM (purple moor grass) rich purple, purple spikelets in upright stems. Height 1m (3ft)
Panicum virgatum 'Shenandoah' AGM (switch grass) glaucous blue-green stems and foliage, airy panicles of purple-tinged pink flowers. Height 2m (6½ft) or more

Autumn

Flower and seedheads are very ornamental and age to silver and russet; foliage colour deepens. Notable grasses at this time of year are:

Miscanthus (all) including M. sinensis 'Flamingo' AGM with golden-orange tints and loose pink-flushed flower panicles. Height 1.5m (5ft) and M. sinensis 'Silberfeder' AGM free-flowering flowerheads.of silver to pale pinkish brown panicles in autumn, remaining through winter. Height to 2.4m (8ft)
Molinia (all) including M. caerulea subsp. caerulea 'Heidebraut' (a) (purple moor grass) golden-yellow autumn foliage and airy plumes of purple flowers to 1.2m (4ft)
Panicum virgatum 'Warrior' (switch grass) blue-green foliage turns yellow. Height to 1.2m (4ft)
Pennisetum villosum AGM (c) (feathertop) plume-like flowers of soft green or white become purplish. Height 60cm (2ft)

Winter

Evergreen grasses and skeletal flower plumes add interest to the winter garden. Some to note for winter:

Acorus gramineus 'Ogon' (v) (e) (c) (Japanese rush) fans of glossy rich-green leaves striped with pale-green and cream. Height to 30cm (1ft)
Hakonochloa macra 'Aureola' AGM arching green-striped bright-yellow leaves, flushed red in autumn, colour persisting into winter. Height 35cm (14ins)
Miscanthus sinensis 'Malepartus' flowerheads of darkest purple-red fade to silver. Height to 2m (6½ft)
Sesleria 'Greenlee' (e) (c) bright green mounds of narrow foliage. Height to 30cm (1ft)
Stipa tenuissima (c) densely tufted with filament-like bright green leaves and masses of softly feathery, greenish-white flower panicles persist into winter. Height to 60cm (2ft)

Evergreen ornamental grasses

Carex dipsacea (sedge) slightly penduluous foliage of dark-green and olive changes to pinkish-bronze during winter. Height 40-50cm (16-20ins)
Cortaderia selloana 'Albolineata (v) (pampas grass) compact clumps of arching narrow white-margined leaves and silvery plumes of flower in summer. Height 2m (6½ft)
Deschampsia cespitosa (tussock grass) (a) rigid mid-green leaves and airy, arching panicles of silvery spikelets in late summer. Height to 2m (6½ft)
Festuca glauca 'Elijah Blue' (blue fescue) densely tufted with distinctive smooth ice-blue to blue-green leaves Height to 30cm (1ft)
Juncus effusus f. spiralis (corkscrew rush) leafless spiralled and curled glossy dark green stems. Height 45cm (18ins)
Koeleria glauca (glaucous hair grass) compact mound of glaucous, grey-green leaves and masses of upright stems bearing cylindrical panicles of silvery spikelets. Height to 40cm (16ins)
Sesleria caerulea (blue moor grass) linear pale, blue-grey leaves and bluish purple spikelets in panicles. Height to 30cm (1ft)
Stipa gigantea AGM (giant feather grass) lax clumps of linear, mid-green leaves and bristled spikelets, golden when ripe in oat-like panicles during summer. Height to 2.5m (8ft)
Uncinea rubra densely tufted, with rigid upright stems and flat mahogany red foliage. Height 25cm (10ins)

Ornamental grasses for colourful foliage

Blue, silver or grey foliage
Elymus magellanicus flat intense blue leaves with summer flower spikes. Height 15cm (6ins)
Festuca glauca 'Blaufuchs' (blue fox) (e) (c) dense tufts of bright-blue leaves. Height to 30cm (1ft)
Juncus patens 'Carman's Grey' (spreading rush) blue-grey leaves and glaucous stems. Height 90cm (3ft)
Helictotrichon sempervirens AGM (blue oat grass) metallic-blue leaves, straw coloured spikelets in summer. Height 1m (3ft)
Panicum virgatum 'Heavy Metal' upright, grey-green leaves and large panicles of tiny purplish spikelets. Height to 1.5m (5ft)

Golden-yellow, red or purple
Anemanthele lessoniana AGM (pheasant tail grass) (e) cascading dark green leaves, streaked orange-brown in summer and winter. Height 1m (3ft)
Carex comans bronze-leaved (e) (c) tussocks of hair-like purplish-brown leaves. Height 35cm (14ins)
Eragrostis curvula (African love grass) dark-green leaves, grey-green summer spikelets persist through winter. Height 1.2m (4ft)
Festuca glauca 'Golden Toupee' (e) (c) densely tufted with bright yellow-green foliage. Height to 30cm (1ft)

Variegated foliage
Carex oshimensis 'Evergold' (v) AGM dark green leaves have a broad central, creamy-yellow strip and short brown flower spikes. Height 30cm (1ft)
Carex conica 'Snowline' (v) (e) (c) small arching tufts of dark green leaves margined white. Height 15cm (6ins)
Cortaderia selloana 'Aureolineata' (v) AGM (e) narrow arching foliage glaucous-green leaves edged rich golden-yellow. Height to 2.2m (7ft)
Luzula sylvatica 'Marginata' (v) AGM rich green leaves neatly margined cream. Height to 80cm (32ins)
Miscanthus sinensis var. condensatus 'Cabaret' (v) wide blades of dark green leaves with bold central white stripe. Height 2.4m (8ft)
Molinia caerulea subsp. caerulea 'Variegata' (v) (c) neat tufts of cream and green foliage. Height 45-60cm (18in-2ft)

Small or dwarf ornamental grasses

Acorus gramineus 'Hakuro-nishiki' (v) (Japanese rush) semi-evergreen fans of glossy, bright-yellow and green leaves. Height 35cm (14ins)
Bouteloua gracilis (mosquito grass) linear mid-green to yellowish green leaves. Height to 60cm (2ft)
Elymus magellanicus linear, flat or folded intense blue leaves. Height 15cm (6ins)
Hakonochloa macra AGM mounds of arching linear, bright green leaves, tinged red in autumn. Height 35cm (14ins)
Miscanthus sinensis 'Yakushima Dwarf' arching blue-green leaves and pyramidal panicles of silky spikelets. Height 1-1.2m (3-4ft)
Panicum virgatum 'Hanse Herms' has rich, reddish-purple autumn foliage. Height to 1m (3ft)
Pennisetum alopecuroides 'Little Bunny' densely tufted mid to dark green leaves with green flowers. Height 35cm (14ins)
Sesleria autumnalis vigorous mounds of yellow-green foliage and freely borne creamy flowers. Height 40cm (16ins|)
Stipa tenuissima (c) densely tufted with filament-like bright green leaves and masses of softly feathery, greenish-white flower panicles persist into winter. Height to 60cm (2ft)

Tall ornamental grasses suitable for screening

Arundo donax (giant reed) and cultivars, stout stems and glaucous mid-green leaves. Height to 5m (15ft)
Miscanthus × giganteus robust species with penduluous dark green leaves on vigorous, tall upright  stems to 3m (10ft) or more
M. sacchariflorus (Maxim.) Hack. (silver banner grass) blue-green leaves and silvery spikelets in panicles. Height to 21m (7ft)
Molinia caerulea subsp. arundinacea 'Skyracer (a) (purple moor grass)mid-green leaves turn clear gold in autumn. Height to 2.1m (7ft)
Panicum virgatum 'Northwind' (switch grass) blue-grey foliage and airy panicles of iridescent purplish-red flowers. Height to 1.5m (5ft)
Pennisetum orientale 'Tall Tails' upright light-green leaves and pinkish-white flower spikes. Height 1.5m (5ft)

Dry sites in full sun/drought tolerant and gravel gardens

Andropogon gerardii (big bluestem) blue-green leaves turn purple in autumn when tall stems bear deep red-purple racemes. Height to 2m (6ft)
Bothriochloa bladhii narrow linear light-green leaves turn red in autumn and silvery spikelets late summer. Height 40-150cm (16-60ins)
Eragrostis spectabilis (purple love grass) rich green foliage covered by dainty pink flowers. Height to 60cm (2ft)
Festuca glauca 'Elijah Blue' (blue fescue) (e) intense ice-blue fine, linear leaves. Height to 30cm (1ft)
Helictotrichon sempervirens AGM (blue oat grass) metallic-blue leaves, straw-coloured spikelets. Height 1m (3ft)
Hordeum jubatum (squirrel tail grass) linear light-green leaves and silky pale green spikelets flushed red. Short-lived but seeds about. Height 50cm (20ins)
Leymus arenarius pale blue-grey leaves and racemes of blue-grey spikelets. Height to 1.5m (5ft) spread indefinite
Pennisetum alopecuroides 'Cassian's Choice' AGM bright-green leaves, yellowish-orange in autumn. Height 90cm (3ft)
Poa labillardierei (New Zealand blue grass) blue-green bristly-edged leaves and arching flower panicles. Height 90cm (3ft)
Schizachyrium scoparium (little bluestem) light-green to bluish foliage and upright flowerheads all turn bright coppery orange-red in autumn. Height 90cm (3ft)

Exposed coastal sites

Cortaderia selloana 'Aureolineata' (v) AGM (pampas grass) (e) glaucous mid-green leaves and summer pink or white pyramidal flower panicles on stout stems. Height to 3m (10ft)
Elymus hispidus AGM bristly, pale silvery-blue leaves and upright flowers. Height to 75cm (30ins) and E. magellanicus mounds of intense blue leaves and lax flower spikes. Height 15cm (6ins)
Festuca amethystina (tufted fescue) tussocks of linear grey-green leaves and lax panicles of violet-tinted spikelets. Height 45cm (18ins)

Shade under trees

Most grasses need good levels of sunlight to flower and grow well but many are tolerant of light or semi-shade. See our pages on plants for under trees and shade planting.

Calamagrostis × acutiflora 'Karl Foerster' large clumps of upright foliage and bronze-pink flowers. Height 2m (6½ft) 
Carex muskingumensis (e) (palm branch sedge) spreading with upright bright green leaves. Height 75cm (28ins)
Chasmanthium latifolium (spangle grass) ribbon-like bright-green leaves and green spikelets. Height 90cm (3ft)
Deschampsia cespitosa (tufted hair grass) (e) (a) dark leaves and feathery silver flower panicles. Height 1.5m (5ft)
Hakonochloa macra  'Aureola' AGM green-striped, bright-yellow leaves and pale green spikelets. Height 35cm (14ins)
Luzula sylvatica (wood rush) (e) glossy dark green leaves and brown flower panicles. Height 80cm (32ins)
Melica uniflora f. albida (wood melic) bright green leaves on gradually spreading rootstock, and white flower spikelets. Height 60cm (2ft)

Moist soil in part shade

Carex (all) including Carex 'Ice Dance' (v) (e) bright green leaves margined white. Height 30cm (1ft)
Deschampsia cespitosa 'Goldtau' (e) (a) mid-green leaves and reddish spikelets. Height 75cm (30ins)
Glyceria maxima var. variegata (v) (variegated reed sweet-grass) cream, green and white striped foliage and purplish spikelets. Height 80cm (32ins)
Milium effusum 'Aureum' AGM rich golden-yellow leaves may be pale green in shade. Height 60cm (2ft)
Miscanthus sinensis 'Morning Light' (v) AGM compact, with narrow leaves finely edged with white, and pink-tinged panicles of flowers in autumn. Height to 1.2m (4ft)
Sesleria caerulea (e) (blue moor grass) pale blue-grey leaves, bluish-purple spikelets. Height 30cm (1ft)

Useful resources

Books

Designing with Grasses by Neil Lucas (Timber Press ISBN 13: 978-0-88192-983-6)
The Plantfinder's Guide to Ornamental Grasses by Roger Grounds (David & Charles Publishers ISBN 0 7153 0638 3)
The Color Encyclopedia of Ornamental Grasses by Rick Darke (Timber Press ISBN 0-88192-464-4)

These books are made available through the RHS Lindley Library

Places to visit

Beth Chatto Gardens, Elmstead Market, Essex
Bressingham Gardens, Diss, Norfolk
Knoll Gardens, Wimborne, Dorset
RHS Gardens Harlow Carr, Hyde Hall, Rosemoor and Wisley
Scampston Hall, Malton, North Yorkshire
Sir Harold Hiller Gardens, Romsey, Hampshire


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