Gardening With Ornamental Grasses

There is no way I could get through the summer without spending at least one column on the attributes of ornamental grasses.  They are in a league all of their own and the month of August is by far the best time to view them.  


Ornamental grasses can be used in many ways in the landscape: from bold specimen subjects to large massed plantings waving in the breeze, as low ground covers, edging or blended into a mixed perennial border.  They work well in containers too.  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.


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 the 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.  


Grasses are also divided into two groups based on their growth habits:

Running Grasses—These are varieties that spread by stolons or rhizomes.  They can form a dense mat of foliage and make an excellent ground cover but beware, some varieties can be invasive so be careful where you plant these types.  Bamboo is a classic example of a running grass (although there are non-running bamboos as well).

Clumping Grasses—These are types that grow in tufts or bunches and can often stand alone as a single specimen.  They have the advantage of not being invasive but, when planted very closely, can also form a fairly dense ground cover.  Blue fescue is a clumping grass that has been used for years as a ground cover.  


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.  Personally, I couldn’t garden without them so if you would like to see firsthand how to incorporate them into your garden, check out my garden next to the nursery.