Purple Fountain Grass Pennisetum advena Rubrum

Purple Fountain Grass is grown for colour and movement. Narrow burgundy leaves arch out from a tight clump like water from a fountain, and from summer into autumn soft, purplish foxtail plumes rise over the top, nodding in any breeze and catching the low sun late in the day. In leaf it sits at about waist height, with the plumes lifting it higher, and from across a garden it reads as a solid block of deep colour in a way few shrubs manage at this size.

The trade is cold. This is a warm climate grass. Frost browns the foliage, and in cold inland districts, or in heavy soil that stays wet all winter, a clump can die outright. In Brisbane, Sydney, Perth and climates like them it behaves as a dependable perennial; further south and up in the ranges, give it a warm, sheltered position or grow it in a pot that can be moved.

Not the fountain grass on the weed lists

Botanists now place this plant in Cenchrus, so you will also see it sold as Cenchrus advena Rubrum. It is easily mistaken for the green fountain grass, Cenchrus setaceus, which seeds freely, is regarded as an environmental weed in Queensland, New South Wales, Western Australia, South Australia and the Northern Territory, and is a declared plant in South Australia. The purple form sets little or no viable seed and is not considered weedy, which is why it remains a garden plant while its green relative is discouraged. Buy it as the named purple form, and if a green fountain grass ever turns up in a bed, pull it out before it flowers. If your block runs into bushland or a creek line and you would rather plant an Australian native, Common Tussock Grass is a clumping alternative that, unlike the purple grass, takes hard frost.

Full sun, free drainage and not much else

Colour depends on light. In full sun the leaves hold a deep wine shade and the plumes come thick; in part shade the foliage drifts toward bronze green and flowering thins out. Plant it in free draining soil, sandy loam or a raised bed if you garden on clay, and allow roughly as much width as height for the arching leaves. Once its roots are down it shrugs off heat and dry spells, which suits it to hot, reflective spots such as gravel gardens, driveway edges and beds beside paving. It copes with coastal gardens set back from the first line of salt spray. In a pot, use a wide container and a good potting mix, and expect to water more often in summer than you would in the ground.

Pairing it with other grasses, and the yearly cut back

Most of the Ornamental Grasses are green, blue or silver, so this one earns its place as contrast. Set in a drift between grey or blue foliage, it makes both colours look stronger. In drier temperate gardens, Blue Fescue makes a low, steel blue front edge with the purple grass rising behind it, though it tends to sulk and rot through humid subtropical summers. Mass planted on its own at even spacing, it gives a moving burgundy band that suits contemporary gardens and wide verges, and the plumes can be cut for vases.

The main job is one hard cut a year. In late winter or early spring, once frosts have passed, cut the whole clump back to a hand's width above the ground, and fresh leaves follow within weeks. In cold districts leave the old growth standing through winter, as it shields the crown. A light feed of slow release fertiliser in spring is plenty; heavy feeding makes the leaves soft and floppy. Pests rarely bother it. If the centre of an older clump thins out, lift and divide it in spring and replant the healthy outer pieces. For more plants that settle in on little water, read our guide to low water gardens.

Choosing a size

This plant is supplied in one size, 300mm, at $75.95 per plant. The size shown is the pot it arrives in, which is the rootball, not the height of the plant. Not sure which to choose? Read our guide to low water gardens.