Cold weather dieback and plant survivalBy Joe Lamp'l
Just when you think spring was here to stay, Jack Frost pays a late-season visit and leaves an ugly mess behind.
All too often, unseasonably warm temperatures in late winter and early spring can cause big problems in our gardens and landscapes. These "spring-like" temperatures often result in many plants and trees breaking dormancy prematurely. Then a sudden drop to below freezing can wreak havoc on tender new growth.
So what should you do when this happens? That depends.
Shrubs
Besides the potential season-ending loss of flowers that bloom on or before June (i.e. azaleas, hydrangeas and rhododendrons), the plants themselves usually fare much better. You may choose to remove dead flower buds (they're gone for the year) for cosmetic purposes. Otherwise, they'll just fall off on their own eventually.
The newly emerging leaves on deciduous shrubs often appear burned or blackened or as though it has turned to mush after a late-season freeze. Fortunately, in many cases (and depending on the severity and duration of the freeze), damage is often confined to the foliage. In a matter of weeks, these leaves will be shed as new growth emerges to replace it.
Newer branch growth and tips are also subject to dieback. Once several weeks have passed and potential new foliage growth has emerged, you will be able to see any stem dieback. Working from the top down, prune dead stems and tips back to the first set of healthy leaf buds at this time.
Evergreen shrubs may also exhibit damage, but usually in the newest tissue toward the top of the plant. Older, thicker foliage further down may or may not show signs of damage. Signs of damage include brown or black discoloration or limpness.
Wait to prune back these plants until it is obvious that new growth will not be emerging from the branches. Usually by late May, new growth will have appeared if it is ever coming back. At this time, you can cut back branches to healthy growth.
Trees
Trees respond similarly to shrubs. Although the foliage on your prized trees might look terrible right now, trees must have leaves to survive. When a late-season cold snap fries the foliage, new leaves will emerge to take their place.
In the event tree branches suffer dieback, you may cut back dead limbs to healthy growth to improve appearance.
Perennials and bulbs
Some perennials and bulb foliage may have taken a hit as well. In the case of hostas, go ahead and remove the damaged foliage right away, allowing the new foliage to come on unencumbered. If the foliage has turned to mush all the way to the ground, go ahead and remove it. New growth should emerge.
For oriental and Asiatic lilies, you might wait a few more weeks to see if new foliage emerges from the top of the plant. Although they may not bloom this year, they will need this foliage to store energy for blooms next year.
I realize this may take a great deal of patience on your part and a willingness to put up with a few "uglies," but don't be hasty cutting everything down or back all at once. Plants need to grow! Putting out new growth is how they recover and continue to survive. Your patience will be rewarded.
Tender annuals
Annuals and warm-season vegetable plants that appear to have melted away are not coming back. Consider this a valuable lesson learned. There is a reason you hear not to put these plants in your garden until after the risk of the last frost has passed.
You can find information on the average date of the last spring frost for your area by calling your local county extension service. This is especially important information for planting tender perennials and annuals. Some years you might be able to cheat Jack Frost. But, just like this season, he can even it out.
(Joe Lamp'l, a master gardener, hosts DIY's Fresh from the Garden as well as a gardening radio show. For more information, visit www.joegardener.com. Distributed by Scripps Howard News Service.)
![PHOTO](javascript:popup("http://img.diynetwork.com/DIY/2007/05/03/SHNS_JoeLampl04_30_07_e.jpg",350,450))
