Fall and Winter Gifts from the Garden: Ornamental Grasses

Karl Foerster Feather Reed Grass

by Dr. Cheryl Boyer

Ornamental grasses have really caught my eye this fall. The way the morning and evening light glitters through the seed heads is just gorgeous.

Never before have there been so many varieties of ornamental grasses from which to choose. Breeders are selecting for landscape performance, foliage color, seed head size and plant size. I think the most interesting feature of most ornamental grasses is the seed head, but foliage color is a close second. There are some newer varieties with deep purple leaves and names like ‘Hot Rod’, ‘Fireworks’ and ‘Heavy Metal’.

Versatile is the word of choice for this category of plants. They can take tough sites, full sun and little nutrients or water (once established). Many are very tall and can screen unsightly features in the landscape while others are short and (let me say it) cute. Yes, cute. Have you seen ‘Little Bunny’ Pennisetum? Adorable. Plant enthusiasts are allowed to call plants adorable, you know.

What about ‘Blonde Ambition’ blue grama grass. Oh yeah. This one is spunky and super cool. ‘Pink Cloud’ muhly grass is literally a cloud of pink blooms. These plants all look great planted en masse as well as in containers.

There are really only 3 simple things to remember about growing ornamental grasses in your landscape: planting time, trimming time and division time.

Planting time is most of the year except for winter. Plant once the danger of frost has passed in the spring, up until the end of September. If you plant them any later than that, say right now (October) when you’re reading this article, it’s really too late. They don’t have adequate time to establish a strong root system and are in real danger of dying when cold weather hits. Better to wait until your investment can grow enough during the growing season to survive the winter (which they do very well, just need time to establish).

I have a bone to pick about trimming time. One of the main attributes I’m focusing on in this article is the seed heads of ornamental grasses. They certainly look their best right now, but they will also continue to look great for the next 6 months or so. This is their time to shine—winter interest is a main feature of ornamental grasses. Therefore…don’t cut them back until February or March as winter is ending and spring is beginning. I have seen far too many grasses cut back in their prime when it’s absolutely not needed. Grasses need to be trimmed to 6-8 inches in the spring in order to let the fresh new growth get through the old biomass. Now, this is where it gets manly, I tell ya. Trimming ornamental grasses requires gloves, long sleeves and serious tools. If your grasses are really big, like Pampas Grass, you might even want a chainsaw and chaps. If smaller, you can probably get away with pruners or hedge trimmers. Compost all that good biomass for organic matter later in the year.

Division time is another time for manly tools. Every 3 to 4 years it’s a good idea to divide most ornamental grasses. By then, the center starts to die out and the plants begin to look somewhat unattractive as a clump. How do you divide grass clumps? With shovels and saws and axes. And maybe a machete—we use those in horticulture more often that you would imagine [sidenote: Can I have one for Christmas?]. Dig those plants out and redistribute them or give them away. I’ve even seen folks try to get rid of their divisions on Craigslist. Hey worth a look if you want some plants for free!

This holiday season, consider glamming it up with the gift of glitter (gift certificate for planting ornamental grasses) and “tooling“ it up Tim Taylor Tool Time Style with some manly gardening tools. You already know what’s on my list.