Garden Notes : Preparing plants for winter, and as gifts
Photo by Susan Safford
Winter moths are sporadically fluttering at twilight. The falling leaves keep accumulating during the protracted type of autumn we have now; they keep landing to add to leaf piles. Before snow arrives — and I hope it does — it is good to remove the leaf muddles from bushes and shrubs, especially the broad-leaved evergreens.
Cass Turnbull, the Seattle gardener and author of "Cass Turnbull's Guide to Pruning," coined the phrase "leaf muddles," I believe. It is a good description of the debris that lodges in the centers of shrubs. Leaf muddles trap moisture, snow, and ice, which in turn weigh down the plant and cause breakage and weaken bark. Long-standing leaf or needle muddles may even house rodents and the seedlings of other plants. So look around and pull them out of your shrubbery.
While removing leaf muddles, be vigilant too about the soil and mulch levels around the plants' trunks, and clear them away if they have crept upwards. Ian Yochems, leader of the first Winter Walk at Polly Hill Arboretum (PHA), pointed out a number of plants there whose trunks, one way or another, have suffered by the burying of their root flare. Many show the yellow plastic flagging signaling that they have been de-accessioned from the PHA collections.
A tree's root flare is the critical interface between tree trunk and soil, where the roots spread out before they disappear into the ground. As the tree grows and ages, the root flare becomes buttress roots, which are the bracing the tree puts out to anchor itself securely where it is growing. The root flare is where the tree "really lives." It must be protected from damaging mowers and trimmers, and be at the correct level to prevent suffocation. Otherwise, water-sprouts and girdling roots are likely to develop, and the tree will never anchor itself properly in the soil or grow well.
Yes, even at an arboretum — with its multitude of responsibilities in caring for many, many plants (three thousand or so at PHA in toto) — trees may either accumulate levels of soil and mulch that are too high for the plant to root well and grow healthily, or be planted too deeply. Despite all good intentions, settling after planting may occur, or rain perhaps washes soil and mulch in towards trunks; and the buttress roots are subsequently smothered.
As Ian Jochems pointed out, trees growing naturally in the woods do not have these problems: they grow at the correct depth from germination onwards. However, 90 percent of municipal and urban street trees, trees that have been professionally planted, have been planted too deeply. One can tell! If the root flare is not visible, or if the trunk seems to go straight downward into the ground like a sign-post, it has been planted too deeply.
I returned home from the walk and went right out to check the root flares of various planted trees here. Sure enough, I found plenty of soil and mulch to scrape away.
Gift growing: seasonal plants
It is not for me to grow the Himalayan blue poppy, or other plants with a reputation for finicky-ness, although such gift plants would probably be enthusiastically received. No, I am sticking to easy opportunities that present themselves. One does not need to be an experienced or trained horticulturalist to grow gift plants, only to plan ahead and to know how to "choose one's battles," as they say. Cuttings of the scented, variegated pelargonium, 'Lady Plymouth,' root easily and make handsome house and container plants, for example.
A florist's mini-cyclamen purchased in the supermarket seven years ago has been a faithful plant companion, setting seed that I have been able to germinate and grow on into offspring, mostly cyclamen-red like their parent. They have beautifully marbled and spotted leaves, which add to the pleasure of growing the little plants and sharing them with friends.
Two succulents, Thanksgiving and Christmas cacti, have been with me 43 and 19 years, respectively. They are two similar but distinct genera, Zygocactus and Schlumbergera, and have been easily propagated and grown on many times, by sticking segments of their weird, flattened foliage into four-inch pots of soil-less mix, such as Fafard's 52 Mix, and then just letting them root and grow.
Place the pots outdoors over summer and return indoors into dark conditions around Labor Day. Retrieve them after two or three weeks; little nubbins cover the leaf tips, which grow and make welcome bloom circa Thanksgiving and Christmas.
Decorative living wreaths may be made from various ivies, both hardy English and Baltic ivies as well as more tender florists' types such as 'Glacier' and 'Gold Ripple.' I select for long trailing stems, the longer the better, and form a flattened, horizontal wreath by twining the stem carefully around itself to the desired diameter.
I want to have the leaves all coming out on one side of the wreath so that when it is laid in a shallow bowl or saucer of water to root, no leaves are submerged. Place the wreaths in bowls containing several small pieces of charcoal and set to root in bright indirect light. With pillar candles these living ivy wreaths make pretty centerpieces. When warm weather returns, the wreaths recycle easily into outdoor containers.
Hippeastrum (amaryllis) and Clivia, which make offsets over time, especially when pot-bound, are excellent subjects for gift growing because they are undemanding but spectacular houseplants. When it comes time to repot the parent plant, separate the offsets and pot up each into its own snug little pot. In the case of hippeastrum, leave the upper third of the bulb — shoulders and neck — above the potting mix.