Garden Notes - Winter solstice

By Abigail Higgins - December 20, 2007

Welcome to winter! Officially the solstice occurs Saturday Dec. 22, 1:08 am EST and about a week later it becomes apparent that the days are longer. The time of the solstice makes me think of the Light. Its absence in nature makes it all the more desired, and I find myself seeking it spiritually, too. My wish is that we, like plants in a garden, may turn to it.

As I mentioned in my last column, winter temperatures that remain stable enhance our gardens' welfare. Ideally, if it is to be cold, let it remain cold; if it is to be mild, let it remain mild. Recent new plantings are the most vulnerable to temperature changes or extremes and it is common for them to be heaved out of the ground by the action of "freeze-n-thaw" frost. Laying down mulch to three inches deep, kept away from trunks, helps to mitigate these effects. Branches, from deciduous prunings or evergreen from recycled Christmas trees, trap and hold snow or leaf debris that benefits the planting beneath. Mulch newly planted living Christmas trees or gift shrubs.

dwarf Alberta spruce
This dwarf Alberta spruce is developing in a reverse direction. Full-sized branches are taking over the little tree, which requires immediate pruning. Photos by Susan Safford. Click photo for larger version.

A revised view of the value of winter clean-up is taking shape from the counsel of the garden world's elite. This view adheres to the precepts of permaculture, an emerging philosophy that encourages the examining and following of nature's patterns. Stylistically, letting perennial bed foliage and seed-heads stand is becoming much more the norm, as propounded by such leading gardeners as Piet Oudolf, Cassian Schmidt, and Keith Wiley. Plantings in this style now exist at leading botanic and display gardens in the United States and abroad, such as the Denver Botanic Garden and Wisley, and are a potent teaching tool.

For years, organic practitioners have touted the value of spring clean-up as opposed to fall clean-up. As in surrounding untended areas, fallen leaves remain in the garden where they lodge, creating a blanket as nature intended. There are caveats with that approach, stylistic and practical. Some homeowners simply abhor a look that is less than "immaculate," although immaculate grounds are not necessarily healthier or more thriving; they are often at odds with permaculture's aims.

The oak forests of Martha's Vineyard produce a particularly durable dead leaf. Piles of them do not break down much over the course of the winter but do hold moisture. If the dead leaves come from maples or other trees, they are less leathery but can mat into sodden layers. In beds and hedges this may be fine, but lawns acquire bare patches and houses acquire rot where the accumulations sit.

Decks, landings, outside stairs, gutters, i.e., all outside wooden or painted appurtenances, are vulnerable to anything that holds moisture on them. For clean-up purposes, these are the most important areas to clear. At the design stage eliminate fussiness and streamline those features that catch and hold debris.

dwarf Alberta spruce
Click photo for larger version.

Dwarf Alberta spruce

The dwarf Alberta spruce, Picea glauca 'Conica,' a favorite for a variety of reasons, is a decorative conical evergreen with a very slow growth rate. It makes a wonderful living tree for the Christmas tree trade as it has many uses in the outside landscape afterwards. Dwarf Alberta spruce are grown and sold in numerous sizes, from smaller than a foot (tabletop size) up to about three or four feet. For design purposes they are often used (some would say, over-used) in pairs, to mark an entrance, walkway, or in cemetery plots. They make wonderful container plants due to their slow growth rate and formal shape.

The tree is covered in dense, miniature needles that give it its unique appearance. The foliage's denseness contributes to a pest, red spider mite, which is common to the tree. These trees dislike being planted close to something. Select a location that is in sun and well away from walls, or buildings that would shade it, heat it, or prevent the soil from receiving moisture. Hot or dry conditions promote the spider mite and contribute to or cause bare spots on the tree. Water the tree well in dry spells and hose-spray the foliage regularly to discourage spider mites.

The dwarf qualities of the appealing little trees come from mutant branches of a regular white spruce that grows differently, or "sport." Nurseries are always on the lookout for these sports for vegetative propagation of interesting new cultivars. The sports, also called "witches brooms," show features discrete from the parent tree's typical form in growth habit, leaf shape, or coloration. Most of the choice specialty evergreens originate in this fashion, as did the dwarf Alberta spruce.

The tree pictured has developed, however, in a reverse direction. It is reverting to its big-tree type by sporting a full-sized branch of regular white spruce, which will eventually take over the little tree and make a vastly lop-sided thing of it. If this happens to your dwarf Alberta spruce, immediately prune out completely the growth that is different, before it has a chance to disrupt the regularity of your tree's shape or to make a hole in the foliage. Watch the tree for future attempts to revert.

Fall cankerworm and winter moth

They're back and all over everything in my neck of the woods. If there is a silver lining to nasty winter weather I wish it would be that it diminishes the reproductive success of the tiny defoliators. They have helped create a lot of firewood. The last few years have not been kind to Island trees (or trees anywhere), a sequence of the caterpillars plus drought, and now the consequences are beginning to appear in tree removal.

After a few weeks that load of firewood, whether dumped or stacked, is likely to shelter wildlife and that wildlife is likely to be rodents. They take shelter anywhere we provide it for them. Stone walls, retaining walls, beneath slabs of bluestone, garden sheds with old sagging doors, the ground under compost piles and, yes, those accumulations of leaves: all these and more are likely spots for hosting critters we would rather not have nearby.

I suggest tossing pieces of rodent bait in as one builds the woodpile. You may not eliminate them entirely but the bait will be in a place that is safe for all except its intended consumers. Maybe it is good to remember why felines were first domesticated. Barn cats provide good rodent control, but they seem to be a thing of the past, like barns themselves, and in any case, a micro-chipped barn cat is an oxymoron.

Merry Christmas!