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Great Gardening by Sally Cunningham

In a recent program called “After the storms: What to do about broken shrubs and trees,” I faced a full house of worried people, all distressed or discouraged about the state of their landscapes. At Plantasia this weekend all the CNLPs, including myself, will be trying to answer: “Should I cut the shrub all the way to the ground?” “Can I tape the split trunk together?” “If the rabbits ate this many of the stems, will they grow back?”

Meanwhile, we’ve only begun to see the damage since many of our landscape plants are still under frozen snow piles. Rough winter, yes!

Beyond normal damage

After any winter we see a certain amount of damage. Many evergreens show browned needles, especially on the windward side. Sometimes windstorms blow shallow-rooted or recently planted trees over, and the freezing-thawing pattern heaves some root balls out of the soil. When we take a chance on a marginally hardy plant (say, a Japanese maple labeled for USDA Zone 6 hardiness), sometimes it dies from a sudden, severe cold snap, especially in the absence of a snow blanket. Deer and rabbits nibble on many landscape plants. Storms take out a few branches from old trees, especially if an arborist hasn’t been managing the canopy load. None of this is a surprise.

It’s also normal that recently planted plants are at the highest risk of death during their first three years in the ground – especially during year one. During those first years the recently established plants need to grow roots to anchor and nourish them; they must be watered thoroughly whenever the root balls start to dry out, and they need to have been planted well (not too high, not too deep) in good soil with proper drainage. Now imagine those at-risk landscape plants going through a few dry spells late last summer and then getting hit with abnormally deep and fast freezes, high winds and, finally, having heavy snow dumped on or thrown at them. What’s a little shrub to do?

Well, they dried out, split, cracked, lost limbs, turned roots up, or became animal food. The damage this winter is well beyond normal.

Many of your problems are individual, if not unique, and professionals will try to help you case by case. Here are some typical problems with basic advice to help you get started with your decisions on what to do.

Q: My birds’-nest spruce (or low juniper, cotoneaster, Chamaecyparis) was crushed when the ice dam (or snow plow load) fell on it. Lots of branches are broken, and the center is smashed. Can I save it?

A: Well if you can’t, next time be sure to place future plants differently – like not under the edge of the eaves and not in the path of a snowblower or snowplow. If a branch is broken, make a clean cut above a viable branch or bud, angling the cut in the direction of the branch or bud. (A pruning class or book would help you picture this.) Never leave a stub. If the crown is smashed, it’s hard to say. Clean up the damaged parts and give the plant time.

Q: What can I do about a split arborvitae? Tape it together?

A: Sometimes you can tape a split trunk together and if the cells under the bark connect it could actually heal – but it’s not easy. Or you may be able to select one shoot as the new leader and cut back the surrounding shoots. Get an arborist or CNLP to help with a valuable plant. Nurseries are trying to obtain and offer you replacement plants that split less easily. Remember not to put the new plant in a vulnerable position.

Q: The rabbits nibbled the bark entirely off the stems of my (forsythia, sprirea, viburnum etc.) Can I cut it down all the way? Will it come back?

A: Where did we get these 4-foot rabbits? Yes, where the snow was deep many shrubs are stripped far up the branches – on my forsythia, too. Many multistemmed shrubs (famously lilacs and forsythias) can be cut to the ground and within two years will rebound. If they weren’t great plants anyway, consider better cultivars. If the shrubs didn’t have every branch girdled, then try a selective pruning method, taking off outside (stripped) branches, cutting other branches to one-third or two-thirds from the top. Topping them is never the right method.

Q: My oak tree lost some large branches on one side and it’s lopsided. One is still attached and hanging down.

A: For large tree limb removal, get a certified arborist. (Many kinds of dangers involved.) For smaller trees – still be careful of whiplash – if the branch is still attached and stripping the trunk bark, cut it off any way you can. Later correct the cuts – no stubs. Always cut limbs off outside the branch bark ridge or collar. About severely damaged trees, I often remember a respected arborist saying: “Trees have dignity; respect them.” At a certain point, take it down.

Q: What will come back and how long should I wait to see if a shrub is alive?

A: If branches of deciduous or evergreen tree or shrubs are brittle and snap off, and you do not see a green layer under the bark, those branches are dead, but wait many weeks to see if new growth appears. Some plants (Buddleias, Caryopteris and hardy hibiscus) wait until early June to produce new shoots.

Q: What about my hydrangeas? Why didn’t they bloom last year, and what about this year?

A: Many H. macrophylla (‘Endless Summer’, big-leaf, repeat-blooming types) will have had buds killed this winter (which often happens in spring here anyway.) Plants will likely survive but may bloom late, in July. Other types such as H. paniculata should be fine.

Keeping plants alive requires right conditions, including proper planting, correct soil and site, and the absence of human or animal damage or environmental disasters. This winter offered almost every possible problem for landscape plants. And it’s not entirely over.

Sally Cunningham is a garden writer, lecturer and consultant.