Posts Tagged late-season freezes

Recovering from a Late-spring Hard Freeze

Freeze-killed new growth on American Holly (Ilex opaca)

Freeze-killed new growth on American Holly (Ilex opaca). Note that — so far — the flower buds appear unscathed.

The damage to one of my hollies (They all looked like this.) in the above photo occurred this past Wednesday, April 6, when the temperature at my house fell to 26.8 degrees. Unfortunately, late tonight and into the early hours of tomorrow before the sun returns, my area’s temperatures are predicted to be lower than this previous event. I am expecting my yard to see temperatures between 23-25 degrees for at least 8 hours. This one is going to hurt. A lot.

I am worse off than many, because I live in an area not yet completely encircled by concrete and asphalt. The heat-island effect that urban/suburban areas generate by absorbing the sun’s heat in man-made materials usually prevents temperatures from falling as low as they do at my house. Plus I live on a hill that slopes to a floodplain. Cold air is heavy and sinks, and as it slides down my hill, it pauses long enough to caress newly sprouted green shoots until they become brown, shriveled sludge.

Magnolia sprengeri 'Diva' after the recent freeze.

Magnolia sprengeri ‘Diva’ after the recent freeze.

If a miracle occurs and the roaring winds now driving in arctic air don’t diminish to stillness, the damage won’t be as bad. But odds are most of the fresh new green growth on canopy and understory trees, shrubs, and perennials will look the way my poor Magnolia ‘Diva’ in the above photo already looks.

This has happened once before in my years here. I called it the Black Spring, because literally every leaf on every canopy tree died. Finally about mid-June, the trees mustered a new flush of leaf growth, but it was a much-reduced push of foliage. That summer was hot and dry with no tree shade to hide in. Such a trauma leaves plants in a weakened state that makes them more vulnerable to disease and insect attacks. So how should you plan to recover from any freeze damage to plants at your house?

Reduce your expectations for the growing season

Perhaps your fruit and/or nut trees produced an abundance of flowers, followed by tender new leaves, as my pecan trees did. If tonight’s freeze kills that new growth, it is likely you won’t see much fruit this year.

My pecan trees are about 40 feet tall, and planted in one of the coldest spots in my yard (before I understood that area’s temperature issues). The growth of one tree was completely killed, as you can see in the second photo above. The other tree was heavily damaged, but still shows some green. It is closer to a tall stand of Eastern Red Cedars, which protected it somewhat.

But no matter. Pecans need two trees for good cross-pollination and nut production. The squirrels will see no pecans this season. And I will need to figure out a way to provide water to the completely killed tree if we go into drought, so that it can summon enough energy for a new flush of leaf growth. And to the other tree, too, if it suffers the same fate tonight.

Range of Wednesday freeze damage to my blueberry flowers

Range of Wednesday freeze damage to my blueberry flowers

Depending on what happens tonight, I may still have a few blueberries to harvest in a month or so. The early-bloomers had already set fruit, and I’m hoping — because they are still tiny — the cold won’t kill them. But as the photo above illustrates, still-blooming flowers were mostly damaged at least a bit. Odds are high that the later-blooming bushes will yield few if any berries this year.

Appreciate the wondrous early spring we enjoyed

Those of us who work with plants know that myriad circumstances can overrule our expectations at any moment. To be sure, we are always at the mercy of the weather. That’s one of the reasons I like to take pictures of my charges frequently during this time of year. I need the glamor shots to lift my spirits after the weather does its worst.

Know your yard’s cold spots before you plant, and know which plants are most cold-sensitive

As I noted above, I planted our pecan trees before I fully understood the microclimate variations on our property. I also didn’t realize the cold sensitivity of deciduous magnolias, native or otherwise.

My Magnolia stellata ‘Royal Stars’ was unscathed by the first freeze. It blooms much earlier, so its flowers were done. And its leaves had been out much longer, so they had toughened up, unlike poor Elizabeth and Butterflies. The buds on my tall native Magnolia fraseri were still tightly closed during the first freeze, but they were swelling. My camera’s zoom lens revealed at least some freeze damage to those buds. Magnolia macrophylla had not even begun to enlarge its buds. The first freeze did not damage it. The reality in my yard is that my beloved early-blooming deciduous magnolias will always be damaged by freezing temperatures. The only variable is the duration of the freeze and the consequent extent of the damage.

Remember local wildlife

Normally by now, I’m tapering down the frequency with which I’m filling seed feeders to encourage disbursement of winter flocks of Northern Cardinals and other feeder-loving species. I always leave out one suet cake until the temperatures remain reliably warm, because woodpeckers and nuthatches are feeding fledglings, and the harried-looking parents seem to really appreciate being able to stuff a bit of suet down a young one’s throat when they can’t find a tasty bug to quell the youngster’s clamoring.

A gorgeous Red-headed Woodpecker sampling my suet feeder.

A gorgeous Red-headed Woodpecker sampling my suet feeder.

My summer bird species are all mostly here now, and their bug supply has been adversely impacted by the freeze. Consequently, I’ve re-stocked the seed feeders and put out more suet. The warblers seem quite grateful for the suet, but I hadn’t seen them visit the feeders before Wednesday’s freeze. As I do throughout the year, I’m making sure all my bird baths are full of clean, unfrozen water.

Poisonous to humans, Pokeweed is a favorite food of Robins and many other native animals.

Poisonous to humans, Pokeweed is a favorite food of Robins and many other native animals.

In the woods adjacent to my house, tonight’s freeze may kill blackberry flower buds, damage new tender shoots of pokeweed, and turn fresh elderberry growth into mush. If that happens, the native fruits my birds rely on will be severely limited. I can’t really offer them anything equivalent, so it is likely they will relocate to areas where their wild foods were not damaged — if they can find such areas.

If a Black Spring darkens my door…

If tomorrow reveals another Black Spring for my yard, I will expect to see many fewer bird species while my trees struggle to re-leaf themselves. If drought appears, I’ll need to add water to challenged plants where I can. I can’t water canopy trees. For them, I can watch closely for signs of dying limbs, and disease and insect encroachment.

My beautiful ash trees are just pushing out tender leaves and flowers. I am worried about their chances tonight.

My beautiful ash trees are just pushing out tender leaves and flowers. I am worried about their chances tonight.

Summer annuals and summer-blooming perennials and woody plants will not be affected by the freeze directly, but the absence of shade provided by canopy trees will stress them, especially if the rains stop coming. My summer vegetable garden should not be too adversely impacted — barring drought or plagues of locusts/disease, etc. I will tend my tomatoes, savor the tang of basil, and do what I can for my damaged charges.

This year's tomato seedlings are safe and warm in the greenhouse.

This year’s tomato seedlings are safe and warm in the greenhouse.

Such is the lot of those of us who work the earth. And the truth, of course, is that we know embracing the bad along with the wondrous good is all part of our journey.

Stay warm, friends.

Stay warm, friends.

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Please, not another black spring

Some years back — I don’t remember how many — my part of the piedmont of North Carolina had an early very warm spring — very much like the one we experienced this year. In response to the 80+ degree F temperatures, all the trees leafed out early. Those that bloom before they leaf out  flowered ahead of their normal timetable. All the spring bulbs and wildflowers bloomed simultaneously, instead of offering the usual succession of color spread over several weeks — very much like what has happened this spring.

That spring some years back, all that leafy enthusiasm was blackened overnight by a late freeze. As I’ve mentioned, I live in a cold spot, so when lows are predicted to be 30, I’m likely to see 25. That black spring killed every new leaf and flower on my 80-foot canopy trees. The week after the freeze, the ground was littered by tiny blackened tulip poplar, sweet gum, and oak leaves. The trees returned to winter’s barrenness.

For a while, I was afraid the trees were dead. However, after two more months, the canopy trees managed to push out a second flush of leaf growth — not as lush as the first — but enough to finally offer shade to the forest floor.

It was June before that happened. Normally, the canopy is fully emerged by mid-April. It was a long, hot, painful late spring/early summer until I finally had the forest shade I rely on to cool my home, shelter birds, and feed wildlife.

Fast-forward to this precocious spring. My spring-blooming ornamental magnolias are nearly done — thank goodness. But the native trees that bloom — redbuds, dogwoods, silverbells, serviceberries, buckeyes, and more are all either blooming or about to bloom — ahead of schedule by a week or more. Likewise, my Rhododendron canescens (Piedmont Azalea), a native deciduous azalea, is just opening its buds — and it’s packed with flower buds this year, promising to be a showstopper in the landscape.

The blueberry bushes are blooming or about to start. The spring vegetables are just starting to put on some size and become productive. And now the meteorologists are predicting a freeze for tonight.

I can cover the vegetables and the azalea. I can’t protect my 20-35-foot blooming understory trees. And I certainly can’t do anything but wring my hands over tender tulip poplar leaves or abundant oak catkins just beginning to release their pollen.

I fear another black spring is about to obliterate my spring landscape. If I’m lucky, the oak leaves are still safely inside their buds. We won’t get any acorns if the flowers die, which is bad news for wildlife, but perhaps we’ll still at least have leafy shade.

I’m very worried about the trees whose tender new leaves have already emerged. When the last black spring happened some years back, our water levels were normal, meaning the trees had plenty of soil moisture available to help them summon the energy for another surge of leaf growth.

This spring, however, we are in a severe drought. Water tables are frighteningly low. Roots will have much more difficulty finding all the moisture they will need for a second try at leaf development. Drought-stressed trees are more susceptible to insect and disease damage. The potential for a downward spiral from healthy forest to barren landscape is very real.

This morning, I felt sleet pellets hitting my face as I retrieved my morning paper. This afternoon, I will be covering as many tender plants as I can — and praying for enough lingering warmth in the canopy to prevent another black spring.

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