Dramatically decorative plants provide three seasons of garden magic

It’s no big secret that I’m no fan of lawns and lawn grasses (I’m currently on a mission to replace as much of the yard’s grass with clover as possible). Ornamental grasses, though—that’s quite another story. Like many gardeners, I evolved into a love affair with ornamental grasses, and now I can’t imagine a garden without them.

Oh, for sure, in the spring they don’t look like anything but a bunch of dead sticks, but as we roll into summer and autumn, they take on delightful texture, make gorgeous sounds as the wind whispers through them…and many produce elegant and long-lasting flowerheads that are eye-catching. As an added bonus, many grasses have interesting colour through the season—not just green!—and great fall/winter colour, too. What’s not to love?

Practically speaking, there are grasses for most places in your garden, and many of them offer more than ornamental value. If you want to create a relatively quick screen to block the view of an unsightly fence or just to add some privacy to your yard, some grasses get quite large and showy. Once established, many are easy care and drought resistant, as well as offering good resistance to weeds crowding into their growing area.

They are useful for stabilizing a sloped area that may be prone to erosion or is hard to mow, and the taller ones can act as effective supports for other perennials.

Most importantly for many gardeners, they are relatively problem/pest free. Best of all, deer do not like the majority of grasses: their tough, sharp leaves (blades) aren’t at all appetizing to Bambi.

Grasses have only two (fairly minor) drawbacks in my mind—some can be challenging to photograph well, and the botanical names of some are a tad daunting to pronounce.

 

Watch the runners

Some people may have encountered variegated ribbon grass (Phalaris arundinacea) in their gardening adventures; also known as gardener’s garters, this is NOT a recommended grass unless you’re planning to put it in a container. It can be highly invasive, running rampant through a garden, and is difficult to get rid of once it gets to that point. The good news is, there are other, perfectly well-behaved variegated grasses to choose from.

Most of the grasses discussed here are clump-forming, meaning they will not run—a few are slow spreaders, which can be very useful if you’re planning a border of a grass like Japanese forest grass, (Hakonechloa) which slowly spreads out but is easily controlled. And while some literature warns about Japanese blood grass (Imperata cylindrica ‘Red Baron’) because it’s not sterile and can revert and cavort off,  but this seems to be an issue more frequently in warmer locales.

 

Grasses can be annual or perennial. This particular fountain grass is annual, so perhaps try one of these before you commit to growing some perennial species

Annual or perennial?

For the new grass grower, being presented with a varied selection at a nursery can be a tad confusing—which ones will prosper here in our region? Which are perennial, and which are only for the season, like marigolds and petunias? Perhaps, if you’re unsure about planting a perennial grass, you might start with one of the highly decorative annual varieties.

Unlike their long-lived perennial relatives, these grow and mature quickly, usually into a small-to-midsize clump, with excellent floral display and great colours. Some annual grasses are also ideal in container plantings, either by themselves as a dramatic display at an entryway to the home, or in mixed plantings. Varieties include a number of fountain grasses (Pennisetum), or Egyptian papyrus ‘King Tut’ and
‘Baby Tut.’

 

Cool season or warm season?

You will often hear people refer to cool or warm season perennial grasses, which may sound a little confusing. This has to do in part with when they start their active growth. Cool season grasses start growing fairly early in the spring, while temperatures are still on the cool side—they tend to want a consistent amount of moisture in the soil or they may turn brown in the heat of the summer. My favourite cool season grass is blue oat grass, Helictotrichon, which has striped, blue-green and white foliage and delicate white, oat-like inflorescences. Other genera include Calamagrostis, (feather-reed grass), sedges (Carex), blue fescue (Festuca) and moor grass (Molinia).

Warm season grasses are slower to get started in the spring—you may even think they are dead, but don’t despair. Have patience, and depending on the spring, you’ll soon see new growth emerging from the crown. Many of the ornamental perennial grasses we grow in our region are warm season grasses—Miscanthus (silvergrass), Chasmanthium (northern sea oats) Andropogon and Schizachyrium (big and little bluestem), Pennisetum (fountain grass) and Panicum (switchgrass). Be patient, and if your plantings are new, mark where they are so that the following spring you don’t dig them up thinking they’re dead. That’s the voice of experience speaking, here. It does happen, even to seasoned gardeners.

 

Making more grasses

Dividing grasses should be done in the spring, when they have plenty of time to establish new root systems. I remember one summer when a friend, new to offering ornamental grasses, divided some warm-season Miscanthus grasses in late summer and repotted them at his nursery—and lost most of them over winter because they simply didn’t have time to establish their root systems before freezeup. Lesson learned!

When you do decide to divide your grasses, you’ll want sharp tools and a strong arm—those root masses are tough and if you’re going to dig the whole plant up and divide it into multiple sections, you want to eat your oatmeal before you go out with the shovel and knife.

One grass in particular, the giant maiden grass (Miscanthus ‘Giganteus’) grows nine to 12 feet in height and makes a massive root ball—I’ve heard of several intrepid gardeners who have used a mini excavator to dig it out. This isn’t a grass for most people’s suburban yards, but it does have its place in some plantings. (Not mine, I hasten to add).

 

 

Great grasses to try

Andropogon, big bluestem: The bluestems are native to North America and as their name suggests, they can get fairly large once established—as much as six feet tall, but not that wide. Their flowerheads are not as showy as some, but their foliage is spectacular through autumn and into fall. ‘Blackhawks’ has purple tips to its foliage and flowers, becoming burgundy-black in fall; ‘Red October’ is a smaller form with brilliant red tips to its foliage, which flush through the foliage as autumn unfolds.

Calamagrostis, feather reed grass: These grasses are much loved by landscapers for commercial plantings—they head up sooner than some of the other grasses, and their upright growth habit makes them a good choice for a privacy screen. Look for the ever popular ‘Karl Foerster’ or the variegated forms ‘Avalanche’ and ‘Overdam’.

Carex, sedges. There are a host of species and varieties of Carex, most of them under 18 inches tall, and many with variegated foliage. They prefer moist areas for best growth.

Chasmanthium, Northern sea oats: This midsized grass has one of the showier flower heads, with sprays of oat-like inflorescences that are a soft green, and fade to a golden tan as autumn unfolds.

Hakonechloa, Japanese forest grass: Shade gardeners, this one is for you—the low-growing grass thrives in shady sites and looks splendid at the edge of a perennial border. ‘All Gold’ is a particularly showy  golden form, but there are also several green-and-gold forms available.

Miscanthus, maiden grass or silver grass: The silvergrasses are known for their showy flowerheads, which last well into autumn or even winter. There are many varieties available, including some with variegation or striping in their foliage. My personal favourite is Miscanthus ‘Purpurascens’ flame grass, which has spectacular fall colour.

Molinia, purple moor grass: These cool season beauties are easy going clump-formers with fine, graceful foliage. They produce long, elegant stems of purplish flowerheads that can more than double the height of the plant. Look for ‘Skyracer’, one of the tallest, or the smaller, front of border gem ‘Variegata’.

Panicum, switchgrass or panic grass: Although the flowers of panic grasses are not as showy as other varieties, most have blue-green or red-tipped foliage. My personal favourite is the bold and big ‘Thundercloud’ but other great choices include ‘Heavy Metal’ and the delightfully named
‘Bad Hair Day’.

Schizachyrium, little bluestem. You may sound like you’re sneezing when you say the genus name, but don’t worry—anyone carrying little bluestem knows what you mean. Another personal favourite, this is a midsized clumper with blue-green foliage that turns red and then burgundy in autumn.