It’s Time to Cut Back
The planting and pruning of roses may get all the press in winter, but there are other things that need doing at this time of the year.
It’s time to plant those tulips (and maybe hyacinths) that have been cooling in the frig. It’s time to spray deciduous fruit trees, especially peaches, with a dormant spray and fungicide. It’s also time to prune these trees.
And, it’s time for cutting back.
“Cutting back” is gardening jargon for the pruning down of herbaceous perennial plants. Herbaceous perennials are those that more or less die back to the roots each winter, sprouting anew in the spring. It’s one way plants survive the cold of winter, where it gets cold.
In our climate these perennials may not die back completely. They look only half-dead, the leaves worn out and ragged, the old flower spikes brown and stiff. If you do not cut them back, they simply make new leaves and flower above the old come spring, but pruning them back tidies the garden and gives these plants a fresh start.
What are some of the plants that can be cut back? Chrysanthemums, columbine, coreopsis, gayfeather, some true geraniums, ornamental grasses that look tatty, evening primrose, physostegia, rehmania, many salvias, Shasta daisies, Verbena rigida , and most yarrows are some common ones.
You can do this cutting back any time in late fall or winter, before February, which is when some perennials begin to actively grow again in our benign climate, but right now is a good time.
You need to be careful because many plants sold as perennials in Southern California are not herbaceous and do not like being cut back. Cut back coral bells, those handsome perennials with the roundish leaves and delicate stalks of frothy flowers, and you will probably kill them. All you need to do is cut off the old flower spikes and remove dead leaves as they appear.
Many perennials are not herbaceous. Even if they look shabby in winter, you must simply put up with it.
Helianthemums, or sun roses, are another example of something often called a perennial, but actually is not. They are technically subshrubs, and should never be “cut back,” though you can certainly prune them like any shrub, to encourage new, less rangy growth. But cut them back too far and you may finish them.
Alstroemerias need to be cut back, but this is not the time. They’re on a different cycle and should be cut to the ground in late summer when the plants are almost dormant.
Other perennials we grow here are on similarly different cycles. Japanese anemones, on the other hand, thrive when cut to the ground in winter and rebound quickly, even though they are not technically “herbaceous.” These flowers that thrive in partial shade and flower in fall, look pretty ratty by this time of the year.
A lot of people just wait until the new spring growth covers the old, but I hack them right to the ground and within weeks, new growth sprouts and the plants look brand new.
My choice of weapons is a Corona No. 5 pair of shears, the ideal tool for “cutting back.” They are actually made for edging the lawn, but are sturdy enough to slice through a whole handful of stems. I grab a handful of stems and cut as close to the ground as I can, though on some perennials you must leave several inches of stubble.
You can put all this in the compost pile or simply keep cutting the old leaves and stalks until they make a nice mulch, leaving them around the base of the plant.
The more-or-less green foliage and brown stems look a little messy for a few days, but then the cut pieces turn brown and then they look like the leaf litter found on a forest floor.
Never send these cuttings to the dump. It makes little sense to send natural organic matter to a landfill one week, then buy bags of bark or soil amendment the next.
