Grasses, grown since the beginning of recorded time for their food value, have recently captured the hearts of gardeners for their ornamental worth in mixed borders and as a substitute for traditional lawn grasses. Not only do they add shape and form to most planting schemes, they also introduce sound and motion into the landscape when they rustle and ripple in the wind. Fortunately, ornamental grasses are easy to grow and maintain, and are virtually pest-free.
The selection of ornamental grasses in local garden centres and mail order catalogues has never been better than it is today. The numbers and kinds of available plant shapes, colours, and sizes are endless. When you also take into account their great versatility in landscape design, it is easy to understand why ornamental grasses are gaining in popularity in leaps and bounds.
Some grasses are grown for their amazing colours - they come in all shades of green, blue-green, gold, cream, red, bronze, and white. There are even variegated and striped grasses that contrast beautifully with neighbouring plants in the border.
Other grasses are grown for their showy and dramatic flower plumes, spikes, or seed heads, which add late summer, fall, and winter interest to the garden. The seeds are also a tasty treat for birds, which can often be found feasting on them, especially during fall migration.
Grasses combine well with almost all plant types and are easy to integrate into existing borders of perennials, annuals, bulbs, shrubs, and trees. Tall varieties add a vertical dimension to plantings and work well individually as accent plants in the middle of borders, or massed towards the back. Medium-sized grasses can also be massed effectively. They provide an excellent transition between highly contrasting plants that would ordinarily clash when planted next to each other. Medium grasses are also the perfect choice for inter-planting with spring-flowering bulbs such as crocus, daffodil, tulip, and squill; the grass foliage easily obscures and masks dying bulb foliage. Low-growing grasses are ideal for edging flower and shrub beds, or for massing as a low-maintenance groundcover. And don't forget that grasses can be used to introduce unusual textures in container plantings.
Grasses can be divided into two basic groups, based on their growth cycles. Choose some of each to create interesting highlights and plant combinations throughout the growing season.
COOL SEASON GRASSES begin growing in early spring and reach maturity before summer's arrival. They tend to consist of shorter varieties and often fade or die back completely during mid-summer's heat. A timely trim encourages a second flush of growth that will thrive during the cool days of autumn. Cool-season grasses can be divided in late summer or early spring.
WARM SEASON GRASSES thrive in plenty of light and hot summer weather, reaching maturity in late summer and early fall. They tend to form tall clumps crowned with large, showy flower plumes and seed spikes. They should be pruned back in late winter, before the new season's growth becomes visible. Divide warm season grasses in early spring.
Grasses can also be divided into two basic groups based on their growth habits. Clumping varieties are usually not invasive, growing slowly outwards from the centre. Grasses to be included in mixed borders should be restricted to the clumping type. Spreading grasses, such as ribbon grass or beach grass, on the other hand, are perfect for creating groundcovers for large spaces in short order. Just remember that, once established, spreading grasses are difficult or impossible to eradicate. Also remember to sink underground barriers at least three feet deep to contain spreading grasses, especially along fence lines so that they don't invade a neighbour's property.
Grasses are not fussy plants; most will grow in any soil type. However, they do best in well-drained soil that has been amended with organic matter such as compost, composted manure, peat moss, or leaf mould. Grasses planted in amended soil will never require the addition of synthetic fertilizer. Light requirements will vary depending on the grass type, as will water requirements. If you familiarize yourself with a grass plant's needs at the time of purchase, and plant accordingly, you will be guaranteed success.
SOME GRASSES TO TRY:
Bulbous oat grass (Arrhenatherum elatius bulbosum 'Variegatum'):
forms bushy, low clumps of cream and green striped leaves, topped by tan-coloured spikes in early summer; drought tolerant once established; a good substitute for the invasive ribbon grass (Phalaris arundinacea).
Fescue (Festuca spp.):
low-tufted clump formers with fine-textured foliage; ranges from blue to green in colour; excellent for edging or massing to form a hillocky groundcover.
Hakonechloa (Hakonechloa macra 'Aureola'):
a slow grass to establish, but an excellent specimen plant for a shady location; leaves are golden yellow with narrow green stripes, arching to one side like a waterfall; fall colour is buff.
Blue oat grass (Helictotrichon sempervirens):
forms perfect, dome-shaped clumps of intensely blue leaves; non-spreader; evergreen.
Moor grass (Molinia spp.):
forms non-spreading mounds of grassy leaves topped by tall branching stems of delicate flowers; short and tall varieties available.
Feather grass (Stipa spp.):
valued for their whiskered flower heads, usually open airy sprays of tiny flowers held above the leaves on graceful, arching stems; readily withstand drought.