As new growth emerges, our fingers often itch to get out in the garden. Late February/early March is an ideal time to start cutting back ornamental grasses. With perennials, early to mid-March is a good time to prune.
Trimming ornamental grasses is simple, unless you have a huge stand of pampas grass or some such. For small grasses, such as blue avena, simply use pruners or small hedge clippers to cut the blades down to 4-6 inches above ground. For larger grasses, wrap a bungee cord or rope around the plant to contain the blades like a pony tail, then use manual or powered hedge clippers or a chain saw below the pony tail to cut the grass back to 6 inches or lower. Once done, you can simply carry the rubble to your compost pile and remove the bungee cord or rope. Be sure to wear gloves to avoid cuts.
As for perennials, you can prune them different ways, depending on the individual variety. For some plants, such as soapwort, it’s often easiest to simply grab a handful of foliage, twist it, and yank it out. Before you do this forcefully, however, give the plant a gentle tug to make sure you won’t be ripping it out of the ground when pulling on it. But if you end up ripping out a small, rooted chunk of the plant, you may be able to transplant it elsewhere.
With orange carpet hummingbird and other short plants with stiff dormant twigs, you can often grab a handful of twigs and snap them off.
For taller, stalky perennials such as agastache, you may find it easiest to treat them like a large ornamental grass, wrapping a bungee cord around the stalks before cutting below with hedge clippers.
Otherwise, you can simply cut perennials to the ground with pruners, although it sometimes takes longer than some of the methods mentioned above.
You can prune many shrubs and trees this time of year, as well, using techniques from Colorado State University Extension.
Leave your roses alone, though. Don’t prune them until late April or early May. Otherwise, frost might kill new growth that occurs when pruning stimulates roses’ hormones. For more information on roses, check CSU Extension’s Pruning Roses.