Gardening With Ornamental Grasses

Ornamental grasses are an interesting class of perennials.  They have some unique qualities that make them an essential part of my borders, as they should yours.  Unfortunately, many gardeners still see them as weeds that either need to be sprayed with Roundup or trimmed with the Weed-Eater.  This column will hopefully find some converts.  

Ornamental grasses can be used in many ways in the landscape: from bold specimen subjects (like Pampas grass) to large massed plantings waving in the breeze, or as low groundcover, edging or even in containers.  Some grasses are grown for their colorful foliage in green, gold, red, cream or white - sometimes even striped or banded.  Others may be valued more for their showy flower plumes, spikes or seed heads.  Several kinds provide dramatic and lasting interest throughout the winter months.  Before you start stressing about these grasses spreading all over your garden, let me put your mind to ease.  Almost all ornamental grasses sold today do not run.  Rather, they are clumping varieties that are very well behaved.

The selection of grasses has never been better than it is today, with an astounding range of height, spread, color, and flowering habit.  There should be room in every garden for at least one variety of ornamental grass, as they can fill a variety of functions.  Tall, upright-growing types create visual interest, especially when used towards the back of the border.  Their fine textures contrast nicely against the coarser foliage of broad leaf shrubs or perennials and they can remain attractive well into the winter.  Medium-sized grasses are effective when massed together, particularly in gardens with a low-maintenance emphasis.  Spring flowering bulbs combine well with these for early season interest.  Low-growing grasses are ideal for edging around shrubs or combining with spreading evergreens.  When mass planted, they will form an attractive low maintenance groundcover.

Grasses can be divided into two basic groups, based on their growth cycles:

Cool-Season Grasses — These begin their growth in early spring, reaching their full size before summer heat hits.  They are usually low to medium sized plants and most are evergreen.  Some may actually brown out in hot summer weather.  Clipping or mowing in July right after their bloom cycle encourages lush re-growth for fall.  

Warm-Season Grasses —These begin growing in late spring, flower, and set seed in late summer or fall, and often provide great fall color.  They should be pruned back in late February or early March.  

The single most important maintenance rule for growing healthy, attractive grasses - with few exceptions - is to cut the foliage back at least once a year.  Cut back grasses just as the new growth begins to appear.  For most grasses this is early spring.  Warm season grasses are generally cut to within a few inches of the ground.  Cool season grasses are usually trimmed down to two-thirds of their full size.  

Ornamental grasses can fill difficult garden niches.  Many species are drought tolerant and will thrive on neglect, once established.  Conversely, there are several varieties that do quite well in damp or boggy soils - some types even thrive in standing water situations.  There are grasses for full sun or dense shade, clay or sandy conditions, and acid or alkaline soils.  You name the situation and there is probably a variety of grass available to do the job

If you have yet to garden with ornamental grasses, hopefully you will reconsider and give them a try this summer and fall.  At least come down to the nursery and give us a shot at converting you - at last count I saw over three dozen varieties to choose from!