There has never been a better time to explore the beauty of ornamental grasses. With so many varieties available,
there is an ornamental grass for every location, from full sun to shade, wet to dry, as well as shallow and poor
By incorporating ornamental grasses into the landscape you are adding form, texture, scale, colour (from flowers
as well as foliage), and movement. They can also be very luminous and translucent.
We are looking for plants that offer year-round interest as well as relative low maintenance. Most ornamental
grasses fit the bill and in addition are not water hogs or heavy feeders, rarely suffer from pests or diseases and
don’t require much more than an annual trim.
Understanding Cool and Warm Season Grasses
Cool Season Grasses:
Actively grow between temperatures above freezing and up to mid 20’s degrees Celsius.
Are mostly evergreen ( a few are deciduous).
Are mostly low growers, 2 feet maximum height.
Mostly flower late winter to early summer.
Warm Season Grasses:
Need warm soil conditions to get growing in the spring.
Grow best when temperatures are above 24 degrees Celsius.
Die back to dormant buds beneath the soil surface in the fall.
Mostly taller growers, 2-8 feet but some as high as 15 feet.
Start flowering mid summer to first frost.
Ornamental Grass Growing Tips
Cut back cool season grasses by no more than two-thirds in early spring as new growth starts (February – March).
Here in the lower mainland you can also give your cool season grasses a light trim in September to remove any
sun burnt foliage from extreme hot dry weather in the summer months. Cool season grasses can rarely tolerate
being cut back hard.
Removing old dead foliage from cool season grasses can be done in several ways: raked out with a fine lawn
rake or course comb. Also, you can run your fingers through the foliage starting from the crown up. This works
really well if you use the rubber coated garden gloves. If you have just trimmed them back then rubbing the
palm of your hand vigorously across the top of the trimmed foliage usually dislodges dead foliage.
Warm season grasses can be cut back down to the ground after the first killing frosts, but most gardeners prefer
to leave the dried foliage for winter interest and therefore cut them back just before or as they start to throw up
new shoots. (March-early April)
If in doubt whether your grass is cool or warm season, the rule of thumb to use is: if there is still color in the
foliage (not all dried and dead) after the killing frosts in the fall then it is probably a cool season grass and
should be cut back by half to two thirds. If all the foliage has died back to ground level and is dried and straw
looking then it is a warm season grass and can be cut back to ground level (2-3 inches).
Take a bit of time planning where in your garden you are going to locate your warm season grasses, as most
have highly luminous foliage and flowers. They will look fantastic when backlit, so plant them where they will
catch either early morning or evening sun for best effect or to the south part of the garden.
A common problem at planting time is planting too deep, as many types of grasses will suffer or even die if
planted this way, so plant to the same soil level as in its’ container. Also, if mulching, do not choke the crown,
taper your mulch down so there is no mulch touching the crown of the plant. Ornamental grasses rarely require
staking. Most ornamental grasses are clump forming and not heavy feeders – they require little or no additional
When dividing ornamental grasses, I recommend that with warm season grasses you divide them every 3-5
years to avoid the center of the plant dieing out. This is best done in the early spring or at latest as new shoots
emerge from the ground. Dig out the very compact root ball and divide it into quarters with a sharp blade or
even old axe! Then replant to original soil depth.
It is not crucial to divide cool season grasses but I recommend that they also be divided every 2-3 years to get
best results. Divide them the same way as with warm season grasses and approximately the same time, just as
new growth starts.
If deer eat your plants look at planting Festuca, Miscanthus, and Pennisetum varieties.
Use ornamental grasses as cut flowers. To get best results from cut flower ornamental grasses, cut before
flower has fully opened. The flowers will usually last a couple of weeks in water, after that drain off the water
and let them dry. They will make an excellent dried arrangement and will look good for over a year.
Books worth looking at:
The Color Encyclopedia of Ornamental Grasses by Rick Dark (Timber press)
The Encyclopedia of Ornamental Grasses by John Greenlee (Rodale Gardening)
Landscaping With Ornamental Grasses by Sunset Books (Sunset Books)
The Plant Finder’s Guide to Ornamental Grasses by Roger Grounds (Timber Press)
Grass Scapes Gardening With Ornamental Grasses by Martin Quinn & Catherine Macleod (Whitecap)
Grasses by Nancy J. Ondra (Storey Books)
A Place in The Rain by Michael Lascelle (Whitecap)
Gardening With Grasses by Michael King & Piet Oudolf (Timber Press)
Bold Romantic Gardens by Wolfgang Oehme & James Van Sweden (Spacemaker)
At Art's Nursery, we carry a huge selection of Ornamental Grasses including both warm and cool season varieties. You can learn more about using grasses in your garden directly from the grower at this years Fall Garden Event, Sept 11-12, 2010. For more information, check our website www.artsnursery.com in early September.
A Few Of Our Favourite Grasses
Red Fountain Grass
Pennisetum setaceum 'Rubrum'
Black Mondo Grass
Ophiopogon planiscapus 'Nigrescens'
Japanese Forest Grass
Mexican Feather Grass
Japanese Blood Grass
By Ewan Mackenzie - Grower of Fine Ornamental Grasses available at Arts Nursery.