Diary July 2007 - Ornamental Grasses

When I first started designing my garden borders, I was fascinated with the many types of perennials and annuals. Then into my 10th or 11th season of gardening I came upon a book that focused on designs by James van Sweden and Wolfgang Oehme. Wow!! They featured gardens that singularly used ornamental grasses or blended them into the perennial border.
Ornamental grasses. I had never heard of them let alone used them! They looked soft and flowing but also dramatic and impressive. There seemed to be so many – small silver ones, soft pink ones and tall striped ones.
Ornamental grasses had been used in landscape design in the early 20th century but then fell out of favour for many years. Van Sweden and Oehme incorporated grasses into their new naturalistic style. They were instrumental in the resurgence of their popularity.
Why do gardeners like them? Most are very hardy, low maintenance, pest and disease free. Some display 4 seasons of interest: after they’ve been green and beautiful all summer, and after their gorgeous autumn plumes, I often hear them rustling in the winter wind!
I have tested quite a few in my garden. I would recommend many and definitely caution you on a few that caused me much dismay and hard work – digging them out!
One of my favourites is Miscanthus sinensis. There are quite a few varieties but the ones I have grow 4-7’ wide and in years with good rain, 6’ high with 2’ plumes!! Now this large a plant may not fit in everyone’s yard, but if you need a big show-stopper, I highly recommend a Miscanthus.
Here’s a shot of my front garden where you can see a striped Miscanthus, some Pennisitum in front and a silvery clump of Helictotrichon sempirvirens a bit farther over.
Pennisetum is considered an annual in my Zone 5A but with a little winter protection, mine comes back year after year. The only thing I’ve noticed is that when I bought it, it had a maroon tint to it but upon returning, it’s changed to a flat green. This year I tried putting it into my containers as the vertical interest and it’s doing very well. The next picture was shot in late May but now, in late June, it’s sending up plumes! Very pretty!
My ultimate favourite, especially in my design days, was Blue Oat Grass (Helictotrichon sempirvirens). It’s very controlled (i.e. not invasive), feathery, and is a gorgeous shade of blue-silver that sets off almost any other colour in the garden. I have at least 10 in my borders and it’s a quiet little star wherever I’ve put it. Here’s a fall shot complete with pink mums and pink-headed Sedum ‘Autumn Joy’.
A few other favourites include small silver Festuca grass (although it seems to be relatively short-lived); tall, sculptural Feather Reed Grass ‘Karl Foerster’ (Calamagrostis) and Variegated Cord Grass (Spartina pectinata). I described Cord grass in my Favourites section: “…a tough-as-nails green and gold variegated grass at the back of my border or near water. Very dramatic when leaves are worked into a flower arrangement. Very difficult to divide. Drought tolerant.”
I’ve tried a few others that have not been as successful but are truly beautiful. Japanese Golden Grass (Hakonechloa macra) is a true delight in a shady spot, but my 3 previous ones never re-appeared in the spring although they are perennials. This year’s addition is constantly being chewed to the ground by one of my ever-favourite garden bunny rabbits!! (Grrrr…….). Another truly outstanding grass is Japanese Blood Grass (Imperata cylindrical). It requires perfect conditions (very well drained soil, not too sunny, not too shady), so when I failed to meet the requirements, it didn’t return. I caught a lovely shot, though, on a garden tour once.

2 very invasive types I had trouble getting rid of were Lyme grass (Elymus arenarius) and Ribbon Grass (Phalaris arundinancea). Plant these at your own risk but otherwise, give the lovely ones a shot! You won’t be disappointed!