PlantAmnesty The Whackables Lavatera, Senecio, Perovskia, Fuchsia and Cape Fuchsia By Cass Turnbull There’s nothing like teaching to bring clarity to a subject. I was cooking up a new pruning slide show last year, “The Whackables, the Shearables and the Untouchables”, when some of my long-held suspicions revealed themselves to be true. These truths pertain especially to the “Whackables”. Many, perhaps all, of the plants so listed belong to a group that horticulturists refer to as “sub- shrubs.” Last year, for the first time, I actually ‘got’ what ‘sub- shrub’ means. That is, they are somewhere between being a hardy shrub (like a snowball bush or a rhody) and a true perennial, flowering plants that die back to the ground every winter (like peony or iris). So, what difference does that make? It means that you prune the sub-shrubs differently than either shrubs or perennials. You can—and in many cases should—cut them way, way back every year. And you should do this pruning in the spring (not in early or late winter, or early spring). Here’s the list of my newly confirmed wisdom: 1) Timing of pruning is important only when plants are being non-selectively headed (as opposed to selectively pruned). 2) Large non-selective heading cuts are more prone to die-back than small cuts. 3) The ‘shearable’ plants (lavender, rockrose, broom and heather) are not the same as the ‘whackables’ (lavatera, Senecio greyi, perovskia, fuchsia and cape fuchsia). There are many other shrubs that are annually or occasionally cut to the ground or to a low framework. They include hybrid roses, red twig dogwoods, and butterfly bushes. You can read about them elsewhere in PlantAmnesty’s pruning literature or Cass Turnbull’s Guide to Pruning. Lavatera Common name is tree mallow, botanical name is Lavatera thuringiaca. I like to plant lavatera in new landscapes because it is such a great immediate gratification plant. It grows really fast and blooms like crazy all season. Its flowers are usually some shade of pink and are reminiscent of hollyhocks (without the rust, but also not quite as good). Used as a cut flower, lavatera is almost immortal in a vase. But it can be a rather short-lived plant in the ground. These characteristics make it excellent ‘filler’ in a new landscape, to be inter-planted © PlantAmnesty Page 1 of 5 PlantAmnesty among other shrubs, giving the home- owner something big and gratifying to look at until the choicer, slower-growing ‘real’ shrubs can get up to speed. I had a client who didn’t like the shade of pink on her lavatera flowers. I thought it was spectacular, especially blooming against the purple smoke bush behind it. So, it came home to live in the ‘orphan’s corner’ on the side of my house. Like so many plants that are heeled-in, it stayed there quite a while. It grew quite tall (8-10’) and blocked the unwanted view from my dining room into my neighbor’s vestibule. I was delighted to see its abundant pink flowers outside my window, month after month, for several summers. Then one winter the tall main stem cracked under a snow load, or perhaps from its own weight. I’ve seen this before; probably this is the reason that lavatera is often cut to a very low framework every year. Such pruning also keeps it shorter and not as leggy as it otherwise becomes. I cut back the broken branch of my heeled-in lavatera, cleanly at about 5’ high (a large non- selective heading cut about 2” in diameter). I had every expectation that it would break bud in the spring, grow out rapidly and bloom like crazy that summer. Instead, the branch died. And unfortunately, there was little branching below to assume the job. Oops! Similarly, I got poor performance from several lavateras, perovskia and Senecio greyi which I cut back to low frameworks in a client’s yard (at her request.) The difference between this and other similar cut-backs to the same plants was the timing and the weather. I’ve concluded that cool or cold weather can set back lavatera, and many of the “Whackables”, especially if the cuts are large. So, it’s better to wait until danger of frost is past, and dormant buds start swelling, that is, mid to late spring. Not fall, not winter and not early spring. Timing is important when plants are non-selectively headed. It isn’t that the plants actually freeze back, but that they’ll be sort of poopy for the whole next year. So, wait to cut them back in the mid-spring (like April or May). Think of it as a rude alarm clock...”buzzz, buzzz, buzzz. Time to wake up and get going!” And another thing—when I told a student to cut back an ‘out-of-control’ lavatera at a renovation site, he assumed that he should ‘clean it up’ too. So, he headed a main stem to about 4” off the ground (okay so far) and then thinned off all the smaller side branches (oops!). © PlantAmnesty Page 2 of 5 PlantAmnesty The large headed-back branch (the cut was about 3” wide) likely would have died back, while all the little headed-back side branches (had they remained) would have lived, grown out and become the new shrub. As they were removed, though, my concern was that the whole plant was more likely to kick the bucket. Big, headed-back branches are more likely to die than little, headed- back branches. ‘Twas no great loss however, since lavatera is, as we now know, “a fast-growing, readily replaced, filler sub-shrub”. Furthermore, I suspect that even when it is pruned correctly, it will still up and die sometimes. Or so I’ve been told. Be aware that there are several species of lavateras (Lavatera sp.) and mallows (Malva sp.) that are true annuals. They grow, bloom, set seed, and die in one year. Some are nice self-seeding annuals; others are self-seeding nuisances. Ask your friendly, neighborhood nursery person for the kind you want to buy. Senecio greyi Common name is Dusty Miller, like everything else of this color. Senecio greyi is what we call a ‘foliage plant’. Its grey leaves are about the size and shape of dimes and nickels growing all along the branches of a mounding, two-foot ‘sub-shrub’. Its summer flowers are little yellow daisies that may or may not be of use to you and your design intents. (Just cut them off if you don’t like them.) It is valuable for the color contrast that it provides with other plants in the garden. It is also an ‘under five-foot’ plant of the sort that is much needed in the average Pacific Northwest garden. Senecio greyi can also get ‘too big’ and a bit leggy. If so, it can be cut back hard in the spring to keep it smaller and somewhat more compact (assuming it gets enough light). What do I mean by “cut back hard”? Well, I mean you can cut it back by about half its size if it’s not too old (try not to make cuts over 1/2” in diameter) or too young (give it a year or two to get established before you start whacking). Here again I advise waiting until mid-spring for best results. © PlantAmnesty Page 3 of 5 PlantAmnesty Perovskia Common name is Russian sage. Botanical name is Perovskia atriplicifolia. Perovskia is another grey plant. Instead of a mound like Senecio, this one is made up of spires of grey leaves with pretty blue flower spikes in the summer—good for your mixed border. I like to say its name with a Russian accent, rolling that ‘r’. It grows to about 3 feet tall. Once established, it also gets whacked-back. On this one you can go really low, to a few inches or even to the ground. Again, do it in the spring, not the fall or winter, as you might want to do while you’re cutting back all your ‘real’ perennials. It’ll look pretty crummy in the winter when the gray leaves freeze and hang limply along the stems. You can brush them off with your gloved hand, leaving the interesting grey, spiraling stems for “winter interest” if you like. They remind me of the outline that your sparkler makes as you whirl it around on a warm, Fourth of July night. I think I’ll declare this plant a “sub-shrub” too. Hardy Fuchsia Botanical name is Fuchsia magellanica. There are many hybrids. For a long time, I’ve daydreamed about designing a yard that blooms in the fall (not ‘turns colors’ or ‘has berries’ but blooms like in the spring). I’d have kaffir lilies, abelias, asters, sasanqua camellias, a lot of those yellow daisies that start with ‘heli’, hardy cyclamen, colchicums, real fall crocus, and hardy fuchsias. I’m sure you’ll think of some others for me. Hardy fuchsias will also be on the ‘horticultural spelling bee’ along with schizostylis, phytophtora, and Elaeagnus. Hardy fuchsias are like the non-hardy fuchsias that you get in hanging baskets for summer, except their flowers are generally less big and blowsy, they don’t bloom as long, and they winter over in your yard as deciduous shrubs. Around the Pacific Northwest they occasionally freeze to the ground, becoming a jumble of sticks covered in ugly dead leaves in the spring. But then they send up a host of new shoots that will become an entirely new, blooming shrub that same year! When this happens, you want to get in and cut out all those skinny dead stems to the ground, or nearly to the ground, before all the new soft, easily broken new shoots arise.