News events that affect your Middle Tennessee landscape
Gardeners shift to salvage mode after freeze
Specialists say patience is vital to recover from damage
Tennessean, Saturday, 04/14/07
Two weeks ago, spring was here in all its glory. Trees had fresh, new growth; dogwoods were blooming; irises were unfurling; azaleas were at their brilliant best.
Then the freeze hit — hard — and stopped spring in its tracks. Now some trees' leaves are black and droopy, irises that were standing tall and blooming are on the ground, dead. Tender new growth on some shrubs looks scorched and dying. Perennials that had begun to emerge are yellow and wilting.
"My hostas look like frozen lettuce," says Margaret Boyd, a garden enthusiast whose extensive garden was hit hard by the recent freeze. "The azaleas are just pitiful-looking."
After an early and warm spring, winter weather finally came to Middle Tennessee.
"I've never seen it like this," says Carol Reese, an ornamental horticulture specialist with the University of Tennessee Extension. Reese, whose office is in Jackson, Tenn., sent suggestions to area Extension agents about how to care for ornamentals that have been damaged by the severe cold.
It's not unusual to have frost this time of the year; in fact, the last expected frost date is Sunday in Middle Tennessee. But it's unusual to have had so much spring-like weather, then sub-freezing temperatures for several nights in succession.
We gardeners will recover from the shock of the spring-into-winter weather. Some parts of the landscape may not be so lucky.
What happened?
The extreme cold came in and damaged — or killed — tender new growth that had come out during the recent warm late-winter and early spring. David Mercker, Extension forester at the University of Tennessee, explains two types of damage that trees have suffered.
Some trees have leaves that are still green but have a rolled or drooping appearance. These trees are experiencing "epinasty," drooping because of temporary relocation of water. "These trees should recover fine," he says.
"Where the leaves appear blackened or purple, they are most likely dead," he says. Ice crystals punctured the cell membranes in the leaves, he explains, causing them to lose turgidity, or stiffness. "Recovery of individual leaves is not likely."
These are the trees that will be most stressed. "As they attempt to re-flush new foliage, they will have to draw upon already depleted starch reserves." He says any additional stress during this growing season — drought, insects, diseases — could cause trees to die.
Some trees, such as poplar and gum, will push out new foliage more quickly than others, such as oak and hickory. "Expect sparse crown with the latter group," he says.
Will plants survive?
Horticulture specialists believe some plants will survive this blow, some will not.
"The survival issue is often unanswerable," Reese says. "It depends on the species, what stage of growth, how cold it got in that site, how long it stayed cold, how well established the plant was and so on."
She advises taking a wait-and-see approach. By now, you may be able to tell if there is any living tissue on some plants. "Some plants may be killed back to larger stems, or even to the roots, but still make a comeback," Reese says.
Plants that bloom on buds formed on last season’s growth, such as big-leaf hydrangeas, will probably not bloom; those buds would have been killed by the cold. Plants that bloom on new growth should be fine, Reese says.
"Most perennials will rebound from the roots, though may bloom later than usual."
On the other hand, anyone who rushed the season and set out tender warm-season annuals or herbs during that warm spring weather now has dead plants that will not rebound. And young or tender trees may have a particularly hard time.
"I’m really concerned about Japanese maples and about dogwoods and younger trees of any kind that have succulent green stems," says Troy Marden, garden designer and host of WNPT-Channel 8’s gardening show, Volunteer Gardener. "We may also see woody tissue damage that may not show up for a few weeks."
Crape myrtles also took a hard hit, Marden says. "When they do re-sprout, some people may find they’ve lost the tops of their crape myrtles."
Japanese maples may have suffered.
But, he says, not to panic: "Wait two or three weeks to see what the damage really is."
Copyright© The Tennessean, 2007