Pennisetum species, and grasses in general, are the great in-betweeners of the planting palette. Like hardy nursery stock they provide form and structure to planting schemes, alongside texture and seasonal interest like so many herbaceous perennials. They also offer an often overlooked aspect of planting - movement.

From the more separate flower spikes of many cultivars in the P. alopecuroides species to the floriferous, cloud-like P. orientale types, the seeding flowers of the genus catch the slightest of breezes, creating flow and even sound.

This is most apparent when the plants are used en masse, as seen in the wild, but they complement other plants when used on a smaller scale in designs.

The larger varieties make good stand-alone options in an otherwise unexciting border, while the smaller varieties are better suited to group or drift planting. A group of a single cultivar will look more natural and be a more effective design element than a group of different varieties.

Pennisetum can be found wild in most tropical and temperate zones, and is in widespread use as a landscape plant in the US, but many species will perform well in the UK climate. P. glaucum is used on a commercial scale to produce the cereal crop millet, but the cultivar P. glaucum 'Purple Majesty' has been developed for adding vibrant colour and ornamental seed heads to planting designs.

Pennisetum species are classed as warm-season grasses, coming into their own in late summer, when flowering really starts to take off, appearing from late June until the first frosts. For maximum hardiness, Pennisetum should be grown in well-drained soil and full sun, though it will cope with light shade in the warmer parts of the country.

The best time for planting out is late spring, but plants can be added to beds, borders and containers throughout the growing season. Once established, most grasses are drought-tolerant but will need some watering in for the first few weeks after planting.

Foliage is best left on the plants through the winter to help protect the roots and early growth in spring. Once threat of frost has passed, foliage can be cut to ground level, though if left too late this may harm new growth. The plants can look a little shabby in dormancy, but spring bedding can be used around the plants to ameliorate this. The grasses could also be treated as an annual bedding plant if budgets permit, as they might not re-emerge in spring in colder areas.

Pennisetum is generally pest- and disease-free and makes an attractive option where low maintenance is a priority.

WHAT THE SPECIALISTS SAY

Pat Humphrey, nursery assistant, Knoll Gardens (National Collection Holder), Dorset "They are good for a wide range of uses, and have always been good sellers for us.

"People worry they're not hardy, but what they need is a sunny, well-drained spot - they don't like getting their feet wet.

"My own favourite is P. alopecuroides 'Hameln' - it is large and mound-forming, and always looks lovely here in the garden. "Another nice one is P. villosum, which is better near the front.

"We also launched a new one, 'Fairy Tails', at the RHS Chelsea Flower Show. This one has a more upright habit, and lovely colouring.

"[Knoll owner] Neil Lucas says he's glad when they're not in fashion because then people will use them properly."

Richard Burt, sales manager, Wyevale East, Swanley, Kent "We sell a lot of Pennisetum but it only tends to be a few select varieties. A lot of cultivars can be tender in the UK climate, even here on the benches. You do need to know what you are picking with this genus, particularly which ones are most likely to make it through the winter.

"The plants really need to get into the ground as early in the season as possible to establish, and need a good draining soil and a sunny spot. They are good for wildlife because the seeds are very attractive to birds.

"P. alopecuroides 'Hameln' is a nice small variety with fine seeds and fluffy flowerheads. We offer the popular 'Purple Majesty' but it really needs to be treated as an annual bedding plant as it won't tolerate winter conditions."

SPECIES AND CULTIVARS

P. alopecuroides, a clump-forming grass, reaches up to 90cm, offering long-lasting summer flowerheads of purple bristles.

P. alopecuroides 'Black Beauty' is a darker-flowered form of the species.

P. alopecuroides 'Cassian's Choice' is a newer dwarf version reaching up to 75cm.

P. alopecuroides 'Caudatum' is a white-flowered form reaching 1.2m.

P. alopecuroides 'Foxtrot' is a tall variety that reaches 1.5m.

P. alopecuroides 'Hameln' is the oldest cultivar, whose dropping habit makes it a popular choice where straighter varieties are too tall.

P. alopecuroides 'Herbstzauber' offers rich red-brown flowerheads in October and November and is a very upright form.

P. alopecuroides 'Little Bunny' displays small, fluffy, cream flowerheads above finely textured foliage. A dwarf form, it reaches just 45cm.

P. alopecuroides 'Moudry' features striking dark blooms, which make it a popular planting option. Tidy foliage is topped in autumn with smoky brown flowers. The plant reaches 90cm.

P. alopecuroides 'Red Head' is a new variety, offering one of the largest flowers in the genus. Flowers emerge burgundy-red, maturing to smoky purple.

P. alopecuroides 'Weserbergland' is similar to 'Hameln' but with a greater spreading habit. Plants are often wider than they are tall.

P. alopecuroides 'Woodside' reaches 60cm and is a sliver-grey flowering form with longer and thinner flowerheads than many in the species.

P. 'Fairy Tails' is a recent introduction. It is upright in habit and grows to 1.2m, with light pink flowers from midsummer onwards, fading to light brown.

P. flaccidum carries reddish brown flowerheads and is an upright form. It grows up to 1.2m tall.

P. glaucum 'Purple Majesty' features deep-purple foliage, stems and flowers, which are up to 35cm long, making it a striking architectural ornamental plant for schemes. It grows to 1.5m. Other breeding work with the species has led to the smaller 'Purple Baron' F1 and 'Jester' F1, a burgundy form that can reach up to 1.1m.

P. macrourum is a tall, clump-forming species with vertical, spear-like stems holding long, thin flowerheads, appearing earlier than most in August and September.

P. orientale Award of Garden Merit (AGM), a short species, carries drooping, pink-tinged flowerheads appearing from late summer.

P. orientale 'Karley Rose' displays striking rose-pink flower spikes and is a more ornamental form of the species.

P. orientale 'Shogun' is taller than the species with more upright, soft, bluish pink flowers from high summer onwards. It grows to a height of 90cm to 1.2m.

P. orientale 'Tall Tails' features narrow green foliage topped with pink flowerheads that reach 1.5m, turning white later in the season. It is 60cm to 1m tall with an upright habit.

P. 'Paul's Giant' is a good choice for its golden orange autumn colour and fluffy flower spikes. A tall variety, it reaches 1.5m.

P. setaceum 'Rubrum' AGM carries striking red-purple foliage and yellow-red flower spikes. The variety is popular for its hardiness (H4) and grows to 1m.

P. thunbergii 'Red Buttons' is a compact, mounding form with bright green foliage and bright red, bristly flowers that appear on fine, straight stems.

P. villosum AGM is a compact, feathery form, which looks great in drifts and mass plantings. It displays pale-cream flower spikes and reaches a height of 60cm.