Hurricane season officially comes to a close here in Wilmington each year on November 30th. That means we can breathe a sigh of relief as we continue to clean up from any hurricane damage. Some of you may have lost trees or shrubs from the storms, and have (hopefully) replaced them with new plants and trees.
Fall (from mid-September through the end of December) is an excellent time to plant new trees. Planting in the fall encourages roots to grow deeper into the ground so that they are well established before the spring growing season, allowing the trees to perform better in the summer. The lower humidity and temperatures in the fall also cause less stress to new plantings.
Did You Know?
Best Hurricane-Resistant Trees
If you’re not sure what trees might work best for your landscape, we've got you covered. Just check out our article on the best hurricane-resistant trees to plant in the Wilmington area.
But what do you do after the trees have been planted? Do they need any special care over the winter? If they’re dormant (have lost their leaves) during the winter, do you still need to water them?
One misconception is that trees don’t need to be watered during the winter. In fact, many trees will benefit from regular winter watering and some, such as newly planted or highly stressed trees, will need that extra moisture to survive – even if they’re dormant.
Water Newly Planted and Young Trees During Winter
Young and newly planted or transplanted trees need a little extra care as they settle in to their new location, regardless of when they’re planted. Be sure the ground is well saturated immediately after planting your new tree, and continue watering deeply and frequently (about once a week) depending on how dry your soil is.
A tree is considered “young” for three years after planting, so continue checking on the soil conditions and adjust your watering as needed. Gradually decrease watering frequency to encourage the roots to grow without supplemental moisture, but ensure your trees are watered deeply at least once a month (every month, including during the winter).
Winter Watering for Established Trees
Healthy established trees can often survive the winter without any supplemental moisture. However, conifers often need a little help. If you’ve ever noticed evergreen trees turning brown in the spring, it’s probably due to not getting enough water during the winter months. Evergreens continuously lose water through their needles or leaves throughout the winter months, and warm winter days or lots of wind can dry them out even more.
However, any kind of tree can suffer from lack of moisture during winter, so if it hasn’t rained for a while, be sure to check on your trees and water them if needed. If in doubt, dig a small hole (about 6-10 inches deep) in the tree’s root zone and feel the soil at the bottom. If it’s dry or only slightly damp, it’s time to water.
How to Water Trees & Shrubs in Winter
When to Water
Water during the day when temperatures are above 40 degrees Fahrenheit. This gives the water time to soak into the ground before nightfall (especially if temperatures are expected to fall below freezing).
How Often to Water
Aim to water trees and shrubs once or twice per month during the winter.
How to Water
The goal is for water to reach down to about 12 inches below ground level – that’s where most of the roots are and where the tree can most easily access it.
To help water soak deeply into the ground, it’s best to use a drip irrigation system or soaker hose (if possible). If you’ve removed or turned those off for the winter, then use a regular garden hose set at a low flow (try putting it on a timer so you don’t forget to turn it off!).
Where to Water
Ensure that you’re watering at the drip line, NOT the trunk of a tree. The roots grow out from the trunk just like the tree branches do, so water in a circle away from the tree trunk. Watering the trunk will mean that water is less likely to reach the tree’s roots, and can encourage roots to stay close to the trunk. You want the roots to spread out so that the tree is firmly rooted when the storms arrive and strong winds blow.
How Much to Water
As a general rule of thumb, trees need 10 gallons of water for each inch of trunk diameter (measure this about 6 inches above ground level). For example, a two-inch tree will need about 20 gallons each time you water. However, plants in windy locations will benefit from a bit more water.
Use Mulch To Retain Soil Moisture in Winter
Mulch isn’t just for looks; it protects the roots and keeps moisture close to the tree’s roots. Consider adding some mulch (such as composted wood chips, shredded bark or leaf mulch) around your trees to cut down on how much you need to water. The one exception here is if the soil drains poorly; in that case, applying a layer of mulch may only make the drainage problem worse.
When applying mulch, make sure that it’s not touching the trunk of the tree. “Mulch volcanoes,” where the mulch is piled high in a cone-like structure around the trunk, do more harm than good to trees. Instead, keep some space around the trunk of a tree and pile the mulch no more than 2-4 inches high.
Ideally, you’d extend the mulch all the way to the tree’s drip line but since that can take up a lot of space (especially around larger trees), extend the mulched area around the tree at least far enough to keep lawn mowers and string trimmers away from the trunk – or up to 6 feet if you can.
By following these winter watering guidelines, your trees and shrubs (especially those planted this fall) will be stronger and healthier next spring and summer. All it takes is a little extra attention to make sure they come through the winter in good condition.