Favourite Ornamental Grasses, Part 2: Cultivars Old & New

When I finally lost patience with an out-of-control Forsythia 'Northern Gold', I decided not to replace it with another shrub. Instead I opted for two ornamental grasses. 

This picture perfectly illustrates why the Switch Grass is my favourite of the two that I planted. When the sun works its way around to the side of the house, the Switch Grass emerges magnificently from the shadows of an early fall morning. The large green clump has a golden crown of tiny buds, that when lit by the sun, become hundreds of sparks of light.

I must be a gardener deep down because, I always find the sight a little bit thrilling.

Switch Grass, Panicum virgatum 'Shenandoah' 

I like this grass so much that I am adding a new variety of Switch Grass this fall. When I took this picture it was still in its nursery pot waiting patiently for me to plant it (40% off clearance item), so I only have a close-up. This new Switch Grass is a bit more compact than the first one I mentioned. It only reaches a height of 3-4 feet and a width of 2-3 feet.

I love the streaks of maroon that mark the foliage and the tiny reddish-brown flowers. In a breeze, the grass swishes and sways in a way that is as elegant as it is graceful.

Red Switch Grass, Panicum virgatum 'Shenandoah' forms an upright clump and has foliage streaked with maroon. Tiny reddish flowers appear in August and are attractive all winter. Trim back to 4 or 5 inches above the ground in spring. Full sun. Non-invasive, clump forming grass. Height: 80-90 cm (31-35 inches), Spread: 75-90 cm (29-35 inches) USDA Zones: 4-9.

There are quite a few cultivars of Miscanthus grass you can choose from. Shape, size, foliage and plume color will all help you make your choice.

I am just beginning to collect them and only have two established clumps along with a few recent additions.

At the front of the house, keeping the Switch Grass company, is a cultivar with beige plumes.

Miscanthus sinensis 'Nippon' is a dwarf form that is perfect for the smaller garden. Though its foliage arches nicely, this cultivar is a more compact and upright plant than many other cultivars of Miscanthus. It has reddish plumes that quickly fade to beige. Full sun. Non-invasive, clump forming grass. Height: 120-150 cm (59- 80 inches), Spread: 60-90 cm (24-35 inches). USDA Zones: 5-9.

A quick note about wether Miscanthus Grasses are invasive: 

Many of the new cultivars are supposedly sterile. A trial conducted at the Chicago Botanic Garden in 2010 found that some cultivars still had viable seeds. Less fertile cultivars were found to be the late flowering varieties. Fine Gardening Magazine has a handy chart comparing the trial results (the number of viable seeds) for common Miscanthus cultivars.

In the backyard is my favourite Miscanthus thus far:

Miscanthus sinensis 'Gracillimus' is one of the most popular cultivars of Miscanthus. Although this grass's mounding shape makes it look quite soft and feathery, I find that the long, narrow green foliage has quite a sharp edge. Maroon plumes that appear in late fall fade to a metallic coppery glow (mid-October in my garden). The foliage becomes beige and looks attractive throughout the winter. Trim it to 6" above the ground in early spring. Also divide older clumps to reinvigorate them in the spring. Height: 120-150 cm (59- 80 inches), Spread: 80-90 cm (31-35 inches). USDA Zones: 5-9.

A large Miscanthus dominates the background in this late summer photo 

of Edwards Gardens in Toronto

Just a quick reminder that most Miscanthus grasses are large. Think mid-sized shrub when you place them in your garden.

Lost Horizons Nursery Display Garden

Any Miscanthus grasses will have presence in the garden, but you can certainly up the wow-factor by choosing one of the many cultivars with interesting variegation. 

Here are a few choices of Miscanthus banded with creamy-yellow. I'll highlight a few key differences after the listings.

Miscanthus sinensis 'Little Zebra' is a dwarf variety that is perfect for smaller gardens. It has the same green foliage banded with creamy-yellow as 'Zebranus' on a more compact plant. Plumes are reddish-pink. Clump forming grass. Full sun. Height: 90-120 cm (35-47 inches), Spread: 75-90 cm (29-35 inches) USDA Zones: 5-9. 

Zebra Grass, Miscanthus sinensis 'Zebrinus' has green foliage banded with creamy-yellow. In winter the foliage fades into tawny-beige. This variety has large coppery plumes. Has more viable seeds than 'Little Zebra' and 'Gold Bar'. Clump forming grass. Full sun. Height: 180-240 cm (70- 94 inches), Spread: 80-90 cm (31-35 inches) USDA Zones: 5-9. 

Dwarf Porcupine Grass, Miscanthus sinensis 'Gold Bar' is again another dwarf variety. It forms an upright clump of green leaves banded with yellow. This Miscanthus has burgundy plumes in fall. 

Clump forming grass. Full sun. Height: 120-150 cm (47-59 inches), Spread: 75-90 cm (29-35 inches) USDA Zones: 5-9. 

Their differences may help you to choose:

Porcupine Grass and Zebra Grass look very similar, but there are differences. Porcupine Grass tends to be a bit more shade tolerant than Zebra Grass (though both prefer sun). Porcupine Grass is stiffer and forms more of an upright clump, while Zebra Grass flares a little from the base of the clump. Zebra Grass is more flexible in a breeze, but this also means that strong winds or rain can cause Zebra Grass to flop a little. One last difference: Zebra Grass prefers drier conditions, Porcupine Grass is happy in more moist conditions.

Chen's garden near Milton, Ontario. See more of Chen's garden here, here and here.

There are also a number of cultivars with striped variegation. Here are a few:

Miscanthus sinensis 'Dixieland' is a mid-sized variety with green foliage striped with cream. Pinkish plumes become silvery as they age. Full sun. Height: 120-150 cm (47-59 inches), Spread: 80-90 cm (31-35 inches) USDA Zones: 5-9.

Misanthus sinensis condensatus 'Cosmopolitan' (also known as Japanese Silver Grass) has wide green leaves edged in cream. Its plumes are coppery-pink. Full sun. Height: 180-300 cm (47-59 inches), Spread: 80-90 cm (31-35 inches) USDA Zones: 6-9.

Miscanthus sinensis 'Variegatus' forms an arching mound of foliage with subtle green and white striping. It has deep rose flower plumes. Height:150- 210 cm (59-82 inches), Spread: 80-90 cm (31-35 inches) USDA Zones: 5-9.

Fountain Grass in my garden.

I haven't had the best luck with Fountain Grass. It is supposedly hardy to zone 5, but I've lost it both years I've planted it. It's a great ornamental grass though, so don't let my experience discourage you. I'm going to try it again in a new location.

Hardy Fountain Grass, Pennistum alopecuroides forms a low mound of arching green foliage that turns bright gold in fall. Its bottlebrush plumes emerge soft mauve and fade to tan as they dry. Full sun. Though this is a clump forming grass, Pennistum alopecuroides will do some self-seeding. Height: 90-120 cm (35-47 inches), Spread: 60-90 cm (23-35 inches) USDA Zones: 5-9.

As well as the perennial options, there are a number of new annual introductions to watch for (hardy only in zones 9 to 11). These annual Fountain Grasses look so wonderful it is worth considering them next spring when you come up with your wish list of annuals.

Pennisetum 'Skyrocket' is a tender perennial (annual in most zones) that forms a low mound of green foliage edged with cream. Skyrocket has sterile plumes that are cream tinged with mauve. Full sun. Height: 24-30 inches, Spread: 16-20 inches. Hardy in USDA zones 9-10 only.

Feather Reed Grass in the Music Garden in Toronto.

In the city where I live, Feather Reed Grass is so overused commercial plantings, it is hard to think of it as interesting or desirable enough to be included in a good public or private garden. It's a popular choice for a good reason: Feather Reed Grass is attractive and very dependable even in the face of neglect. For that reason, I find it hard to hold Feather Reed Grass's popularity against it. 

Feather Reed Grass, Calamagrostis x acutiflora 'Karl Foerster' is an upright grass with green plumes that mature into wheat-like spikes. This cultivar was the Perennial Plant of the Year in 2001. It has a non-invasive, clump forming habit and is adaptive to a range of soils and moisture conditions. Full sun. Height: 90-120 cm (35-47 inches), Spread: 60-75 cm (23-29 inches) USDA Zones: 4-9. 

Feather Reed grass, Calamagrostis x acutiflora 'Avalanche'

If you want to take the use of this particular type of ornamental grass up a notch, try one of the new cultivars that has a bit of variegation in its foliage. Here are three possible options:

Feather Reed Grass, Calamagrostis x acutiflora 'Avalanche' has narrow green foliage that is striped with white down the centre. Feathery greenish-mauve plumes in summer turn into wheat-colored spikes in fall. Non-invasive habit. Full sun. Height: 90-120 cm (35-47 inches), Spread: 60-75 cm (23-29 inches) USDA Zones: 4-9. 

Feather Reed Grass, Calamagrostis x acutiflora 'Elorado' is very similar to 'Avalanche' but is a little taller. Non-invasive habit. Full sun. Height: 120-150 cm (47-59 inches), Spread: 60-75 cm (23-29 inches) USDA Zones: 4-9. 

Feather Reed Grass, Calamagrostis x acutiflora 'Overdam' again has quite similar variegated foliage with plumes that age to a creamy-white. It is not as showy or as vigorous as 'Avalanche'. Non-invasive habit. Full sun. Height: 90-120 cm (35-47 inches), Spread: 45-60 cm (18-23 inches) USDA Zones: 5-9.

One more member of the Calamagrostis family of grasses:

Korean Feather Reed Grass, Calamagrostis brachytricha forms a narrow, upright clump that has silver and pink plumes that fade to cream as they age. Non-invasive habit. Full sun, but will tolerate a bit of shade. Average to moist soil conditions. Non-invasive, clump forming grass. Height: 90-120 cm (35-47 inches), Spread: 45-60 cm (18-23 inches) USDA Zones: 4-9.

Ornamental Grasses and Grass-like plants for Shade

Most ornamental grasses require full sun to thrive, but there are grass options for part-shade and shade. Japanese Forest Grass, Hakonechloa likes moist (emphasis on moist!) part-shade. 

Japanese Forest Grass, Hakonechloa at Edwards Garden in Toronto

Japanese Forest Grass, Hakonechloa in a private garden in Mississauga, Ontario.

There are a number of cultivars of Japanese Forest Grass available for shade. Here are two:

Hakonechloa macro 'Aureola' forms a low mound of arching buttery-yellow and green foliage. I have discovered it is quite slow to grow and does not do well in dry or drought conditions. Part to full shade. Clump forming grass. Height: 30-65 cm (12-25 inches), Spread: 45-60 cm (18-23 inches). USDA Zones: 5-9.

Hakonechloa macro 'All Gold' forms a low mound of arching golden-yellow foliage. Tiny insignificant green flowers. Morning sun and afternoon shade for best color. Clump forming grass. Height: 15-20 cm (6-8 inches), Spread: 30-45 cm (12-18 inches). USDA Zones: 5-9.

An unidentified Sedge figures in the foreground of this shade and part-shade section of a private garden near Uxbridge, Ontario.

Another grass-like perennial that likes shady conditions is Sedge, Carex. It's a great plant to mix with hosta for textural interest.

Here there are two grass-like Sedges tucked under the small maroon tree. I have posted about Jamie's shady woodland garden here, and in the coming months, I will be doing a new post of the same garden in summer.

Variegated Japanese Sedge, Carex morrowii, Laiche japonaise 'Ice Dance' is a grass-like perennial that forms a low mound of tufted green leaves edged in white. It likes moist, rich soil, but most of the Sedges in my garden seem to do fine in somewhat drier conditions. It's evergreen in habit. Height: 20-30 cm (8-12 inches), Spread: 30-45 cm (12-18 inches). USDA Zones: 5-9.

Gold Fountain Sedge, carex dolichostachya 'Gold Fountains' forms a fountain-like mound of green leaves edged with yellow. The foliage turns brown in winter. Clump forming grass. Part to full shade. Height: 25-30 cm (10-12 inches), Spread: 45-50 cm (18-20 inches). USDA zones: 5-9.

The third post in this series will cover care basics for ornamental grasses 

and will suggest some companion plants.