When to CUT BACK Ornamental Grasses
There is probably no group of perennials that more clearly points out the differences between two distinctive types of gardeners: the relaxed gardener and the neatnik. With a relaxed gardener, the very idea of cutting back their ornamental grasses won't have even occurred. Neatniks, on the other hand, already have their fingers on the pruners and are feeling rather itchy to get on with the task. If only those grasses didn't look so great still!!
You are welcome to define yourself in whichever group fits you best, but here are our recommendations... and all rules are easily and harmlessly broken if your itchy trigger fingers insist.
- Tall autumn-flowering grasses: These mostly look spectacular right now and as the weather cools they develop their almond-tones for winter, with plumes still held aloft well past the New Year. Wait to trim until early to mid spring, if you can. These can have great winter effect but that's a subjective thing, up to each gardener to decide for themselves. If you prefer to look at cut-down stalks, trim them down to 4 inches whenever you want. Pictured above is one of this group, Miscanthus sinensis 'Malepartus'.
- Edging or border-front grasses: Blue Fescue is a classic example. These truly want to stay evergreen for the winter, and we recommend leaving them alone until spring, then using scissors to trim off any brown or damaged leaves. In no time they grow new foliage during the cool spring weather.
- Midsized grasses, middle of the border: Switch Grass fits into this group. They still look great in late fall, but any sort of major snow or ice storm will have them flattened during the winter and looking a mess. The answer might be to trim these down to 4 inches once your ground freezes hard, or on some sunny winter day when you need to get outside and do something.
- Evergreen Sedges: The very popular Japanese Sedges and also the strange bronzy types from New Zealand (I call them "everdead") also want to remain evergreen. We suggest leaving them alone and giving a light trim in spring only if they look shabby. They grow best anyhow in regions like the Pacific Northwest where winter snowcover is sketchy at best, and they continue to look great all winter.
If you're confronted by numerous clumps of tall grasses to cut back, hand shears are going to lead to carpal tunnel if you're not careful. Here's a great use for an electric of gas hedge trimmer. You could tie the grasses up first with twine, then make one clean cut near the ground. There, they're already bundled to put out at the curb. If they are headed for the compost pile, trim them down in layers from the top, cutting across about every 12 inches. Then just rake up the debris and haul it away. Some gardeners trim it in smaller pieces and just allow it to land on the ground as a mulch. Needless to say, neatniks will hate that idea!
