Apart from the various utilitarian species of grasses used for lawns (see Grass seed for lawns), there are quite a number of grasses grown purely for ornament. Some are annuals, others are perennials and some, the bamboos, are woody-stemmed. Not all are hardy; some need greenhouse treatment or, at best, maybe grown outdoors as half-hardy annuals during the summer months. The height range is wide; some bamboos reach nearly 6m (20ft), while one or two dwarf grasses seldom exceed 16cm (6in). Few are grown purely for their flowers, although the pampas grass, Cortaderia selloana, is grown as much for its feathery plumes of flowers in late summer as for its foliage effect. In the main the ornamental grasses are foliage plants, often variegated, sometimes bluish-green in color.
They are, in general, easy plants, not at all fussy about soil. A few are inclined to ramp and should be planted with care, but if the right place can be found for them, where they can be allowed to spread at will, they will make handsome features for much of the year. Otherwise, they are reasonably easy to control with the spade. One such vigorous plant, Phalaris arundinacea picta, is known familiarly to gardeners as ribbon grass’, lady’s garters or gardener’s garters. Its leaves, prettily striped with white, are about 1m (3ft) long and a few plants set out about 30cm (1 ft) apart will quickly make a large clump.
Another grass which grows even more rapidly is Glyceria aquatica variegata. Fortunately this needs very moist soil and it is often in boggy places that something is needed with precisely this habit, to cover the ground rapidly. It will, in fact, do best in shallow water by the side of a pond or where a pond overflows to keep the soil continually moist. Provided space is not wanted for other decorative bog plants, the glyceria can be left to its own devices. But it is unwise to plant it near less robust plants as they will be overwhelmed in time. The main attraction, again, lies in the sword-like leaves which are striped with white, but in spring and again in autumn, this variegation is partially concealed beneath the delicate pink or pinkish-bronze flush. The typically grassy flower-heads which rise on spikes above the leaves in summer are brown.
Another white-striped grass is Miscanthus sinensis, a plant which older gardeners will recall as Eulalia japonica. This is an impressive plant for an isolated bed in a lawn or as a background to a border as its graceful blue-green leaves are 1.6m (5ft) or so long, with whitish midribs. The variety variegatus is less tall and the midrib stripe is whiter. Other good forms of this Asiatic grass are gracillimus, in which the leaves are more slender and arching in habit and lack the central stripe, and, perhaps the most attractive, zebrinus, in which the 1.5-2m (5-6ft) long, 1 cm (1/2in) wide leaves are transversely banded with yellow. Even taller than these is M. sacchariflorus, from Japan, in which the leaves may, in good soil and sheltered position, reach 2.5-3m (7-8ft). There is an attractive form of this, aureus, in which the leaves have a central gold stripe.
There may not always be room in the garden for a clump of such a tall grass as this, but such considerations of space hardly arise with the pretty form of the native meadow foxtail grass, dignified with the long name, Alopecurus pratensis foliis variegatis. This is a tuft-forming grass, its narrow leaves, little more than a foot tall, striped with yellow. This grass is sometimes used for bedding purposes and two more which may be used in the same way are Molinia coerulea variegata, about 37cm (15in) tall, with very narrow, white-striped leaves, and the even dwarfed Holcus mollis variegatus, another tufted grass, its leaves variegated with silver.
In complete contrast with these dwarf grasses, is Arundo donax, the Provence reed, which, when well grown, may tower to 3-4m (10-12ft) or more. The best forms of this are macrophylla, with larger leaves, nearly 5cm (2in) wide blue-green in color, and variegata, in which the leaves are variegated with silvery-white stripes, although the latter form is not as hardy as A’.. donax itself which, in any case, should be given some form of winter protection. The less tall A. conspicua, from New Zealand, which bears 0.6m (2ft) long panicles of silky flowers, which open pinkish, then turn white, late in summer, also needs a little protection in winter. This is a plant which should be given a fair amount of room, and for this reason, it is often grown as a lawn specimen.
There are a number of hardy annual seed sown all easily raised from sown in spring outdoors, in the same way as other hardy annuals. Some are more decorative than others, and some are of more interest to the flower arranger who needs material of this habit and texture, than to the gardener at large. They include such grasses as Avena sterilis, known as animated oats, about 1m (3ft) tall, and Agrostis pulchella, one or two Bromus species, the little quaking grass, Briza minor, Hordeum jubatum, the squirrel-tailed grass, Lagurus ovatus, the hare’s tail grass, and Panicum capillare, all in the height range of 30-46cm (1-1 1/2 ft).
Another hardy annual, often grown for the sake of its large hard, grey seed receptacles, is the 0.6-1m (2-3ft) tall Coix lacrymajobi, known as Job’s tears. The receptacles are hard enough to be used as beads.
Less hardy are Pennisetum caudatum and P. longistylum, both about 0.6-1m (2-3ft) tall and both graceful grasses with large feathery flower-heads. P. ruppellii is somewhat taller and equally graceful. All should be treated as half-hardy annuals and sown under glass in March or April or outdoors in May.
But the most ornamental of these tender grasses are the maize or Indian corn varieties, all forms of Zea mays. Z. m. japonica quadricolor is the most spectacular of these as it reaches 1.6m (5ft) and its leaves are prettily striped with white, yellow and rose on the normal green. Other handsome varieties are Z. m. gracillima variegata, about lm (3ft), and Z. m. japonica, about 1.3m (4ft) both striped with white and both useful as pot plants for the cold greenhouse or conservatory, or outdoors in summer bedding schemes to give height and subtropical effect.
The woody-stemmed grasses, the bamboos, possibly because they were over-planted years ago, have to some extent been neglected in recent years. Some, such as Arundinaria anceps, which may reach 4m (12ft) or more and Semiarundinaria fastuosa, which frequently reaches 6m (20ft), are both too tall and too vigorous for small gardens, although they are excellent in the right places, in moist soils and positions sheltered from wind, where there is ample space for them to spread as they will do by underground stems. But the bamboos, on the whole, are graceful plants and a clump of the right kind makes a pleasant feature in the smaller garden. Two such species are Sasa chrysantha, about 2m (6ft) tall, its leaves yellow striped, and Semiarundinaria (Arundinaria) nitida, sometimes a little taller than this, with slender purplish canes. These are excellent for limited areas by the waterside or in moist but not waterlogged woodland soil.