Cleaning up after a rough winter


Endless Summer is a reblooming bigleaf hydrangea variety that is likely to have come through the harsh winter unscathed. (Istockphoto)
Adrian Higgins
Gardening columnist April 2

April is the month when nature reminds us that we live in two climates. Amid the days of welcome briskness or drizzle we might get two or three days in the 80s. This jolt causes plants in bloom to hasten their display. For the cherry blossoms, say, this precocious heat is as damaging as a gale or a freeze.

Knowing this may prepare us for some drama, but it is also worth realizing that this April is going to be more exciting than most, for better and worse.

Adrian Higgins has been writing about the intersection of gardening and life for more than 25 years, and joined the Post in 1994. He is the author of several books, including the "Washington Post Garden Book" and "Chanticleer, a Pleasure Garden." View Archive

The coldness has significantly delayed flowering of early displays of daffodils, magnolias, quince and cherry trees, so when they erupt now in early April, there will be the frisson of a floral glut, a compression of early and later beauties. The delay increases the risk of blooms being run ragged by early heat and late frost, the twin banes of the April gardener.

Should these tribulations cause general despair? No. (This is spring in Washington, for gardeners there will be many moments of long-awaited bliss.)

But the other consideration for anyone with a yard this spring is the widespread damage from the type of long, cold winter that used to be common here but has become rarer in the past quarter-century. Our zone shift encouraged adventurous gardeners to use more tender plants, which, by their nature, take more of a hit in a bad year. But even hardier broadleaf evergreens are looking rough. Some are showing a little leaf burn from freeze damage, others are showing a lot. Some of these plants are dead, but most are not, and they will be fine even if the damage lingers until they grow new leaves between now and June.

Even on the same plant — boxwood or Japanese camellia, perhaps — the condition is variable and instructive. Shrubs that are sheltered from wind and sunlight and those under the sheltering arms of a tree, for example, suffered far less than those on exposed sites.

This would be a good year to be in the business of selling rosemary plants; I have only seen one so far that has survived, and that in a walled garden in Georgetown.

We will be clamoring for rosemary plants and other herbs (lavender and sage, too) and will probably be tempted to return to tougher rosemary varieties such as Arp, which I find somewhat coarse.

Some shrubs may have died back to the ground but will resprout. This used to happen a lot with fig trees, but I suspect established ones will be okay. A gardening neighbor with a mature bay laurel, a plant notoriously iffy in our climate of yore, cut his back hard to stubs. The wood is light, pale and apparently alive.

The point is that if you are convinced a cherished shrub is dead, don’t be: It may return with vigor from its established roots. More likely, and less painful, is the prospect that something with leaf burn or leaf drop will grow fresh foliage in the coming weeks.

The acid test is to take your thumbnail and scratch a twig: If you see green, the plant is alive and kicking. A dead branch, by contrast, will remain brown beneath the bark and will snap if you bend it.

Many gardeners around here have warmed to a shrub named Chinese loropetalum; as with viburnums, some varieties grow to 10 feet or so, but there are compact varieties half that size. They have attractive purple foliage and pink spidery flowers and are tough in summer’s heat, but now every specimen I’ve seen has complete leaf injury. As bad as these lorapetalum look, they scratch up nice and green.

The ubiquitous nandina looks mauled but can be cut back hard and will regenerate from suckers. I have seen privet screens with a lot of foliar injury. You can either wait for fresh growth or rejuvenate hedges by cutting them back to just nine inches or so aboveground. Trim new growth a little in early summer to promote bushiness.

Mophead and lacecap hydrangeas should be left alone: Wait to see what sprouts over the next few weeks. Keep the fresh shoots and remove dead stems to clean up the plant, which may see diminished flowering this year. The rigors of the winter may prove a selling point for the new reblooming hydrangeas that have been developed to shrug off the type of winter damage that harms traditional macrophylla and serrata varieties. The novel types include Endless Summer, Penny Mac and Blushing Bride.

I have seen azaleas that just look desperate: Many have leaves a sickly puce color or they have simply dropped their foliage. If you leave them alone, they should be all right, even the most tender evergreen satsuki and indica types, said Barbara Bullock, who cares for the azalea collection at the U.S. National Arboretum.

The old leaves naturally drop as new growth emerges in the spring — the freezes have dispatched them early and conspicuously. The flower buds were dormant enough to have survived. Freezes in the early 1990s caused defoliation of the arboretum’s predominant Glenn Dale azaleas, she said, but they refoliated and produced their annual flower show, famous citywide.

She does, though, expect the peak azalea season to be pushed back from late April to early May.

If you were thinking of grooming your azaleas with a little branch trimming — not shearing — this might be the spring to do so. The pruning will allow the plant to put more energy into flower bud production for next year, Bullock said, but don’t trim more than one third of the shrub because you will be reducing the flower display this spring.

Unscientifically and intuitively, I think this winter’s depths haven’t reversed our trend toward warmer winters. I think we should continue to use thrilling if more fragile plants and expect to replace them every few years.

The rosemary destruction, for example, has come with a silver lining. I allowed one to get too big, to the point it was robbing a vegetable bed of precious light. I was going to remove a living and robust plant this month, but now can simply and virtuously dig out a dead one. Death, where is thy sting?

Read past columns by Higgins at washingtonpost.com/home.

@adrian_higgins on Twitter

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