Tidying Up Your Greenery for the Fall
Now that fall is here, do you tear out that patch of lamb’s ears than died during summer? How far can you cut back the Mexican sage? Should you prune a rockrose or ceanothus that’s grown too large? What about “deadheading”?
Just how do you care for the “new” garden, the drought-resistant or “sustainable” landscape?
That was the subject of a day-long seminar by Los Angeles landscape designer Robert Cornell for his clients, held in a garden he’d designed, an interesting idea in itself, because, as he pointed out, few professional gardeners can afford to do anything more than “mow, blow and go.” Nowadays, you need to know how to care for your own garden.
He prefers the term sustainable to drought-resistant, because these new gardens encompass more than simply saving water. A sustainable landscape takes into account all of the things that go into or come out of a garden--water of course, green waste, even the energy expended, or resources used, to make garden chemicals. Part of his seminar had to do with that kind of maintenance.
But the fun (the owner of the garden and I had a hard time not joining in) came when he took the pruning shears, weeding fork and other garden tools, out into the garden and began showing how to tidy up.
Most of the plantings in this Pasadena garden are drought-resistant, new, and few gardeners have much experience with them. After the heat of summer, they need a tidying up, to prepare them for the wonderful rainy, growing season ahead.
Patches tend to die out in small-scale ground covers such as lamb’s ears and the new Phlomis russeliana . He showed how to clean these out, mulching any bare areas to protect them against rain and irrigation runoff.
Later in the fall, you can dig up healthy plants from the main clump and fill the voids. This also works for good old gazanias.
From the new ornamental grasses he removed fistfuls of dead blades and suggested cutting a miscanthus completely to the ground since this is one of those grasses that goes completely dormant in winter. If you have a grass you’re unsure of, Cornell suggested playing it safe: “Only cut back what’s already turned brown.”
Many plants needed deadheading. He cut off the spent agapanthus and kangaroo paws, showing how to cut the flower stalks close to the ground. If you only cut them off above the leaves (easier), you’ll have a mass of dead, stumpy stalks in a few years.
Some stalks are actually pretty--dried arrangements in the winter garden--but eventually they have to come off. Agapanthus are one, turning a lovely bleached tan in time and if you wait long enough they are easy to simply pull off. Don’t try this too soon on any seed stalk or you will also pull up some of the plant. They’re got to be really dry.
Cornell admitted that deadheading, the removal of spent flowers and sometimes stalks, was his least favorite garden chore (mine too), but it makes an incredible difference in the look of a garden.
Sure enough, as soon as the plants were deadheaded and dead patches in ground covers cleaned up and mulched, the garden looked dramatically better.
Other new perennials needed cutting back in varying degrees. A lion’s tail, still in full bloom, had some of the older, dead stems cut out and he did the same thing for a Mexican sage, just coming into fall bloom. This perennial will bloom at least twice each year if you cut off the dead flowers in summer, and then cut back the plant almost to the ground in early winter.
He said you could also cut the lion’s tail nearly to the ground (that means about a foot off the ground, trying to cut just above new sprouts) and that it would rebound and remain a more manageable size.
Cornell also tackled one of the new Canary Island lavenders, a difficult plant to clean up because there are so many flower spikes and they never stop coming. He grabbed handfuls, live ones and dead, and then cut them off, going back afterward to individually shorten some of the remaining spikes, nipping here and there with the shears so the plant didn’t look “sheared.” Sort of like layering hair and, in fact, Cornell calls it “feather pruning.”
Penstemon have always puzzled me. It’s a hard plant to tidy up. Cornell suggests lightly cutting off spent blooms, again making cuts just above new sprouts, but he also suggests completely cutting out old, thick woody growth.
Some of the helichrysums can be a handful. In this garden a variegated kind (the chartreuse ‘Limelight’ is more common) had quickly overgrown its spot and was smothering a neighbor. These fast, rambunctious perennials are best cut back branch by branch, making all cuts just above another branch so there are no stubs, to preserve the soft, spreading look of the plant.
Going slowly, you can easily reduce the plant by about half without it looking any less lovely, but a wise gardener allows at least six to eight feet of space in the first place.
Couldn’t you just chop away with a hedge shears, until it was the right size and completely constrained? There’s no place for a hedge shears in the new garden, according to Cornell.
The way to prune anything is to cut back one branch at a time, with the shears or a loper. That’s why professional gardeners simply don’t have the time, and end up “poodling” everything--cutting shrubs and large perennials into nasty round balls.
The native ceanothus and Mediterranean rockroses were two shrubs Cornell suggested not pruning (and I can add that hard pruning of ceanothus is a quick way to kill them). If they get too big for their spot, it’s better to remove some. Cornell suggested just a little tip pruning to control growth and remove old flowers.
He also thinned and shortened a large shrub acacia, the elegant knife acacia, by removing overly long branches, always back to another, and taking out one entire trunk, preserving the graceful shape.
Natural shape and form is definitely an important part of the new garden, and fall clean up requires finesse and no hedge shears. I don’t know about his clients, but I for one couldn’t wait to get home and practice the art, getting out the Corona shears and filling the compost bin. Satisfying work indeed on a warm, dry autumn day.
