I invite you to think about growing tall ornamental grasses for a moment.
- You may not like flowers because they’re a lot of work to prune and pick and clean up after.
- You want something in your garden besides evergreens and bushes because you think those plants by themselves are boring.
- You’re tired of mowing the lawn all the time but you want something the neighbours will tolerate and you want to do as little work on it as is gardening-ly possible.
- Your better half has ruled out silk flowers and you clearly don’t know where to go next.
Why Grow Ornamental Grasses
You might try an ornamental grasses garden.
- You don’t have to mow it.
- Grass is now fashionable beyond belief.
- Grass plants are mostly hardy and might only require a simply yearly cleanup.
- There are ornamental grasses to grow that range from the very short to the very tall.
- Grasses can be left to their own devices to grow all summer and provide something of interest in the garden during the flowerless winter months.
- They’re less work than other perennial flowers
Note that I say “might” require a yearly cleanup because it you decide not to clean up the grass garden in the spring, not many people will notice the lack of attention. Exuberant new growth will cover the sins of a lazy gardener. And, I note this is experience talking here.
Where to Grow
Ornamental Grasses are really for sunshine gardens and while a few might tolerate light shade, both the grasses and gardener will be happiest when they are performing in full sunlight.
Ornamental grasses also do best in soils that don’t have a lot of clay in them; they prefer a well drained site and the more compost you give them, the happier they will be. Remember that in nature, grass provides its own compost and mulch by virtue of its decaying stems and leaves.
It’s easiest to divide this plant and it does much better with a spring division. As soon as you see new green grass blades in the late spring, dig and divide. Fall divisions simply don’t work as well as when the plant is just starting to grow.
I tend to cut mine back (when I do) in the spring. I like the look of the plant in the late fall and winter.
But it’s totally optional when you cut them back – spring before they start growing or fall when you put the rest of the garden to bed.
A weed whacker or set of shears is necessary for the bigger clumps.
I also note I’ve tried not pruning them at all to see what happens. If there was a heavy snow load, some of the clumps tend to fall over in the spring. But for the most part, the taller varieties stand there until the newer shoots start to grow and then they rot and tend to fall over. The key here is “tend” to fall over. In some years, I’ve seen the old and the new stems coexist for some time with the new shoots holding up the old. Bottom line: I now prune them down first thing in the spring.
Taller ornamental grasses include such stalwarts as:
- Feather Reed Grass (Calamagrostis x acutiflora). There are several varieties of this grass on the market including ‘Karl Foerster’ the 2001 perennial plant of the year winner that grows four to six feet tall is a slow spreader and blooms at the end of July into September. This variety will also tolerate more shade than other taller grasses.
- ‘Overdam’ is a newer variety with green and white striped leaves and tan flower spikes that seem to last from mid-summer right through to fall. It is a bit shorter than ‘Karl Foerster’ so the two of them combine to make an excellent combination planting.
- Fountain bamboo (Fargesia nitida) is another tall plant with a clumping or non-invasive growth habit that reaches eight feet tall and higher in slightly warmer climates. Put this one at the back of the garden in protected areas.
- Miscanthus is a wonderful species of grass for the ornamental grasses garden and they too will tolerate some light shade. This giant silver grass (M. floridus) will easily hit six to eight feet tall and is hardy down to my zone five garden. One of my favourite plant catalogues calls it “monstrous but not invasive”. Just my kind of background plant.
- Silver banner grass (M. sacchariflorus) is another tall grass that I have planted around my pond just for its brilliant fall silver flower spikes. Unfortunately, this grass does not belong in any garden where the gardener is afraid to use a shovel regularly; it can be quite invasive once established.
- The fountain grasses (M. sinensis) have been one of the few grasses I have grown over an extended time in my own garden. I particularly like maiden grass (M. sinensis ‘Gracillimus’) for its arching stems and pink coppery plumes. Unfortunately, my garden is a touch too cold for it and while it survived, it started late and finished too early to flower regularly.
- A newer variety ‘Grosse Fontaine’ is supposed to be earlier blooming with silver plumes and I’ll be planting it this year to trial it. This one is another giant and should reach an easy eight feet tall.
- Switch Grass. One of the nicest ornamental grasses I saw last fall in trial gardens was blue switch grass (Panicum virgatum) and I think the most outstanding variety of this grass was one called ‘Heavy Metal’. It has metallic blue foliage whose growing tips turn red in the fall giving a wonderful glow to the garden. This is fully hardy and should hit five to six feet tall if grown in the full sun; do not try this one in the shade.
- ‘Prairie Sky’ is another blue switch grass and while it too has metallic blue leaves, in the fall it turns a honey gold colour. I think they’ll be superb contrast and intend to plant them together.
- Pennisetum. There are several fountain grass varieties I’m considering putting in the garden but I’m going to start with the species Pennisetum alopecuroides itself. This makes an excellent cut flower with its soft-mauve bottlebrush flower spikes and I think it will look good as part of the fall window box designs. Watch Out For This One!
- Ribbon Grass. The one grass I will recommend you stay away from is the Phalaris arundinacea or ribbon grass. This one is what gentle garden writers like to refer to as “fast growing” while more direct types simply call it a garden thug almost impossible to eradicate once established. It has distinctive and quite attractive variegated leaves (that’s why it is planted by unsuspecting gardeners) but you really should let someone else have it in their garden and admire it from afar.