True grasses belong to a vast plant family which includes bamboos. They are native throughout the world. A few grasses are commonly used as lawn grass, but many others are utilized for their stately habit, feathery inflorescence, or for their colored leaves. Some have decorative seed heads, often suitable for drying.
What constitutes grass
Grasses belong to the Poaceae family, and are either evergreen or deciduous, annual or perennial. They have arching or erect stems which are usually round and hollow, with regularly spaced nodes easily visible in the jointed stems (culms to be exact) of bamboos. The foliage is borne in 2 ranks from sheaths, which can be peeled back or split. The plants can be yellow, red, silvery blue, or shades of green. Many grasses under cultivation have variegated leaves and/or stems either lengthwise on the plants or in cross-bands.
Delicate inflorescences come in the form of planicles, spikes, racemes of tiny spikelets, and are usually feather and light, with a subtle color. Many can be used fresh or dried as indoor displays.
Grasses have a variety of uses in the garden. Imposing varieties like pampas grass (Cortaderia selloana) make impressive specimen plants, and others, like hair grass (Aira elegantissima) make great ground cover. Many can be included in mixed borders, where their softer curves and vertical lines can provide a nice contrast to more rounded, broad leafed plants.
Cultivation
Most grasses need little maintenance once established. The usually prefer full sun and like moist, poorer soil that drains well. Feeding is not often needed. Some prefer damp soil and do well near a water feature.
Hardy, container grown grasses can be planted year-round. Tender grasses should be planted in the spring. In places with heavy rainfall, very well draining, gritty soil is important, and stone chips over the soil make a good winter top-dress. Bamboos ought to get freely watered until they are established.
Vigorous and invasive grasses can be grown in containers to restrain them, or barriers such as thick plastic sheeting can be placed in the soil around them as a barrier. Otherwise, cutting back invasive roots with a spade in spring (when new grow comes), then once more in mid to late summer may work. Cut perennials to ground level in autumn or in early winter unless they have decorative leaves or seed heads in which case you can wait to late winter. Tender grasses should be cut back in the spring.
Grasses can be propagated from seed, which is sown as soon as ripe, or may be divided from rhizomatous and clump-forming varieties in late spring to early summer. Divisions can be better off in pots until established, before planting in the garden. Use moist but well drained soil mix in a cool place with bright filtered light.
Bamboos
For full article, see: Bamboo
Most of these woody-culmed perennials originate either in tropical or subtropical regions, many from East Asia. Most are frost tender, evergreen plants, though some are from temperate regions and can take a hard freeze. Bamboos can be low-growing (like Pleioblastus pygmaeus var. distichus) or very tall (like Phyllostachys aureosulcata 'Spectabilis'). Bamboos are popular as screening or hedging plants, as specimen plants, or as decorative ground-covers. The foliage is elegant and ornamental, and is sometimes variegated with green, yellow or cream.