A chilly week

No doubt, there will be few treks through the garden over the the next week. While unpleasant, overnight temperatures forecast to fall into single digits should not be much of a problem, though cold over an extended period following a dry autumn is reason for concern. With long established plants in this garden, desiccation and cold damage are lesser issues, but worries increase as temperatures approach zero. While it is necessary to check on ponds and scattered winter blooms, even on the coldest afternoons, strolls will be brief.

Following several days with temperatures remaining below freezing, a large section of the koi pond is covered in ice. The pipes that circulate water must be monitored occasionally, but this is a minor concern.

Variegated winter daphne is marginally cold hardy for the area, but it rebounded quickly after cold winters when flowers were lost and stems were pruned.

In recent decades, severe cold has been rare, but repeated nights below zero several years ago damaged marginally cold hardy daphnes, loropetalum, and edgeworthias. With lows to six or seven below, all survived, but with damage to stems that required extensive pruning. Gardenias purported to be cold hardy, were not, and all succumbed.

Emerald Snow loropetalum tolerated cold better than purple leafed cultivars, but this witch hazel relative could not survive increasing soil dampness. when a shallow spring became more active.

Flower buds of edgeworthia are watched closely for early color through January, with flowers opening late in the month in a mild winter.

As temperatures drop into the twenties and below, leaves of rhododendrons and Daphnipyllum curl for protection. A few gardeners wrap burlap around evergreens, or fill wire baskets with leaves for protection, but this should not be necessary for temperatures above zero.

Leathery leaves of Daphniphyllum curl for winter protection.

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Time to head south?

Despite daily pleadings by my wife that we head south, we will not be going anywhere as an extended period of cold moves in. Certainly, it’s tempting, but one cannot drop everything each time nighttime temperatures drop into the teens. Very likely, this will not be our winter’s low, and the worst of it is that the cold is forecast to last for a week and a half. A day or two here and there are not so bad, but at least for today the sun’s out and there are a few scattered flowers in the garden.

In recent days, I’ve seen the first color as buds of the Vernal witch hazels (Hamamelis vernalis, above) swell, and though flowers are not likely to open fully for another week, the color is now more easily seen. Flower color of Vernal witch hazels ranges from a ruddy red to yellow, and is rarely brightly colored, though today’s yellow seems to be.

While ‘Underway’ mahonia shows no signs of imminent flowering, all other autumn/ winter flowering mahonias (Mahonia x media) are blooming, with signs that this will continue for several weeks. One of several ‘Winter Sun’ mahonias (above) began flowering in early November, and it shows no signs of fading along with others that started a few weeks later.

While ‘Ogon’ spirea (Spirea thunbergii ‘Ogon’) will be covered in small white blooms by mid March, there have been scattered flowers in recent weeks that are not damaged by cold nights. When I first noticed this flowering several years ago, I expected this might effect late winter flowering, but if there are diminished blooms it is hardly noticed. The floral display in late December is minimal, but welcomed with few other flowers.

Admittedly, I am negligent in keeping proper records of what I’ve planted, and where, so I can note today only that several snowdrops (Galanthus) have begun flowering, without knowing the particulars that are of critical importance in recommending an early bloomer. Most snowdrops in the garden will flower in February, when they are very welcome, but I’m happy to have a longer period of bloom.

Ready to flower, or not

Several hellebores with Christmas rose (Helleborus niger) genetics appear ready to flower this third week of December, but experience tells that these could bloom next week, or remain in this state for another ten weeks. In recent years, this group has flowered as early as late December, or more typically sometime in February, only a bit earlier than Lenten rose (Helleborus orientalis) crosses.

If my druthers count, I prefer the earlier flowering since many other hellebores will not flower until late January at earliest, even in the mildest winter temperatures. Flowers of hellebores are likely to last for two months, longer in the cold, so the only disappointment is when early blooms are buried under snow for an extended period.

A more regular challenge is that deep piles of leaves must be removed for flowers to properly develop, and again so that flowers can be seen. I take full advantage to rest through the winter months, and rarely get around to clean up until leaves are wet and matted. I am, however, encouraged to get to work with the possibility of late December blooms.

More than flowers

While flowers of mahonias, witch hazels, and a variety of bulbs capture attention through the winter months, more matters of interest can be discovered by the curious gardener. In this garden, no more than a few hours are spent in winter labor, but regular afternoon strolls are rewarded with more treasures than only flowers.

While stems of the purple passionflower vine have died to the ground, ‘Waterloo Blue’ remains evergreen into mid December. A new flower started in a spell of mild temperatures in November, but the flower was damaged by repeated freezes prior to opening.

Rankin jasmine appears determined to flower through the winter despite recent nighttime temperatures in the upper teens. Flowers are ruined by the cold, but buds open with the next mild afternoon.

Dark leaves only slightly mottled by lacebugs do not detract from the winter appeal of ‘Dorothy Wycoff’ pieris. The red flower buds will gradually swell until flowering in early March.

Some berries of purple beautyberry (Callicarpa dichotoma) persist into early winter.

Several seedlings of the white beautyberry are scattered about the garden, so presumably birds harvest and scatter the berries.

Male and female organs on this ‘Sekkan-Sugi’ cryptomeria (Cryptomeria japonica ‘Sekkan-sugi). Pronounced yellow foliage in areas with less humidity is more muted in this Virginia garden.

Birds have stripped seed from most seedheads of hostas.

Seedlings of Northern sea oats (Chasmanthium latifolium) can be an abundant nuisance, but they are allowed to remain to sway in the winter breeze. Stems of grasses and perennials are cleared in late winter, or at least prior to new spring growth. This allows birds to feed on seeds, but more importantly, the delayed clean up allows the gardener to rest up for a busy spring.

Not too cold

No doubt, readers to the north are amused when Virginians talk about cold. Of course, this is relative. I’m certain Virginians scoff upon seeing Floridians in winter jackets on a cool day in Orlando. I sympathize with northerners who must endure longer, colder winters than ours, but I’m only a bit envious of residents of the deeper south. I’m pleased to be right where I am. I wouldn’t mind slightly warmer winters (and less humid summers while I’m dreaming), but it seems those are in our future whether I want them or not.

Winter jasmine begins flowering in January or February, depending on winter temperatures.

This area (the mid Atlantic region) seems an excellent balance of just enough cold to grow many conifers, as well as flowering trees and shrubs that require chilling hours that the deeper south doesn’t experience. At worst, winter starts here in November, and rarely do freezing temperatures stray much into March. But, even in the mildest winters, such as earlier this year, there’s enough cold and grayness that gardeners (and everyone else) looks forward to spring.

Hellebores with Christmas rose genetics can flower in late December, or in mid February.

I expect that further north it’s not possible to have flowers in the garden through every day of the winter, and it’s not like this part of northwestern Virginia is in the tropics, but temperatures that rarely dip for long below ten degrees allow an array of winter blooms to cheer the winter weary gardener. I am surprised that few area gardeners take advantage to plant for winter flowers, though hellebores seem to be gaining favor.

As autumn turns to winter, I look forward to flowers of mahonias and stray leftovers of hybrid camellias. Both will occasionally flower into the new year, with mahonias dependably flowering into mid January when they are joined by Vernal witch hazels.

Vernal witch hazel is less variable than other winter flowers, blooming in mid January.

As winter temperatures are wildly variable, so are flowering times. There are years when blooms of the late winter flowering leatherleaf mahonia overlap into January with ‘Winter Sun’ and other mahonias that begin flowering in November. On occasion, hellebores might begin flowering in late December, though mid and late February are most common.

Snow on Winter Sun mahonia

Twice, I’ve purchased shrubs labelled as our native Common witch hazel (Hamamelis virginiana), then waited for late autumn flowers that delayed into January, confirming its identity as the similar, but winter flowering Vernal witch hazel (Hamamelis vernalis). No matter, the winter flowering witch hazel is a treasure, filling the garden with its scent on a still afternoon. Flowers of Vernal witch hazel fade slowly in the cold, so flowers often remain when hybrid witch hazels with larger and more fragrant blooms appear in mid February. Happily, rarely is it too cold to get out into the garden to enjoy.

Collecting mahonias (and other treasures)

A handful of hybrid mahonia cultivars (Mahonia x media) are barely distinguishable from one another, but I’ve determined to obtain one or more of each. Multiples are necessary to plant in varied conditions, so at least one if not all will thrive. That I often cannot recall which is which after several years is inconsequential, and fortunately, none have failed to survive, though ones in shade perform more poorly than those in more sun.

Several ‘Winter Sun’ mahonias have been in the garden for nearly a decade. In this time all have survived temperatures to six below zero, and multiple nights below zero with only minor cold injury. While seedlings of early spring flowering Leatherleaf mahonia are not unusual, the lack of bees through the cold months rarely allows pollination of the late autumn flowering hybrids.

Yes, I am an incorrigible collector. Not a hoarder, I think, but curious to include in the garden as many of the varied favorites as can be found. Not only mahonias, but a variety of trees, shrubs, and perennials. In defense, there are plants that are quite nice that I’ve planted only one of, so I am capable of restraint.

‘Marvel’ is a recent introduction, with leaves that are spineless except at the leaf’s tip. No information is available in references to show that ‘Marvel’ is a Mahonia x media hybrid, but it’s upright form, leaf structure, and late autumn flowering lead to this conclusion. The foliage of ‘Marvel’ is lighter green in color only due to nitrogen deficiency, for a plant that wore out the fertilizer in its container in the garden center. I expect growth in the spring will be similar in color to other mahonias.

It is likely that there are variations between mahonia cultivars in mature size, or perhaps one is more or less upright than others, but in early years following planting these differences are not readily apparent. The flowers are similar, if not the same, with most notable differences occurring with sunlight exposures that also effect timing of flowering. While ‘Winter Sun’ in part sun begins flowering in early November, another with less sunlight begins several weeks later.

Flowers of ‘Charity’ are shorter and held more upright, but I suspect this is due more to habitat rather than a difference in cultivars.

What purpose is there for planting hybrids ‘Winter Sun, ‘Underway’, ‘Charity’, and ‘Marvel’, along with several spring flowering Leatherleaf mahonias (Mahonia bealei), and early autumn blooming ‘Bejing Beauty’ that is similar to ‘Narihira’ and ‘Soft Caress’ mahonias that have proved not to be sufficiently cold hardy for this garden? Curiosity seems a suitable answer that masks possible mental deficiencies that my wife would offer as explanation.

In mid December, Flower buds have developed on leatherleaf mahonia. Flowers could appear as early as late January in a mild winter, but more typically in late February to early March. Leatherleaf mahonia has a more sprawling growth habit than the upright hybrids, and it tends to spread much wider.

Leatherleaf mahonia will occasionally begin to flower in late February, but typically flowering starts in late February followed by small, purple grape-like fruits that birds pluck soon after ripening. This results in several seedlings each year, some of which have been allowed to grow on while others are weeded out.

A wet snow

There is no reason for concern with this morning’s snowfall, at least not in this garden, though there are reports that areas nearby have greater accumulation. Though the snow is wet and branches are arching, there will not be enough in this garden to cause any damage.   If there is a potential complication for areas with more snow, it is that in this unusual late autumn many brown leaves have not fallen, and more of the wet snow clings to branches.

The snowy view from the kitchen window.

In any case, it’s December, and snow is not unusual. There is no question that it transforms the garden, and as a temporary ornament it’s lovely, particularly when the gardener is satisfied that no injury will result.

Nandina berries shine through the snow. Some tall branches of nandinas arch under the weight of this wet snow, but there should not be enough accumulation to cause a problem.

The unusual sight is the few flowers poking through the snow, not camellias and mahonias with blooms that are not unusual in December, but the few scattered flowers of reblooming azaleas and Rankin jasmine.

Most of the sczattered flowers of Autumn Amethyst azalea are hidden beneath the snow, but several buds rise above.

Flowers of camellias will be ruined with nighttime temperatures in the teens expected this week.

Flowers of Winter Sun mahonia will not be damaged by temperatures in the teens, with several mahonias just beginning their winter flowering.