WINTER INJURY

We are seeing a number of different types of trees and shrubs that have apparently suffered damage or died over the Winter. It seems that the most affected are those shrubs that retain their leaves over the winter such as Boxwoods, Euonymus, Holly, Azaleas and Rhododendron. But some plants seem to have just up and died. Japanese Maples seem to be particularly hard hit as well.

boxwood winter injuryThe Boxwoods shown in the photo are an ‘extreme’ example. These shrubs should be fairly dark green in color. The red arrow points to the color these shrubs should be. These Boxwoods will not recover and will need to be removed and replaced.

While any winter can be stressful to certain trees and shrubs, this past winter was particularly devastating with its 30 to 60° below zero wind chills. This is why we tell folks to water trees and shrubs going into December if we experience a dry Fall. It is important to fully hydrate plants prior to ground freeze to limit possible damage.  At the very least, we recommend not planting Boxwoods. They seem to suffer damage far more frequently than any other plant.

Note…Any time you see winter damage on plants, don’t be hasty and remove them. Hand snipping will remove whatever browning exists and then wait to see what new growth appears in Spring and early Summer. If the damage is minor and the plant is still aesthetically pleasing to you, you won’t need to remove it.

On a separate note, we are also telling folks to avoid planting any Spruce trees because of the growing Rhizosphaera Needle Cast situation which we mentioned several times last season. If you need evergreen or pine type recommendations, we suggest planting Hemlocks and White Pine in more shady areas and Concolor Fir, Vanderwolf and/or White Fir in more sunny areas. Avoid Blue Spruce or Colorado Green Spruce.

Trees that retain their leaves all winter

Every year we receive several calls from clients asking why their Oak, Hornbeam or Beech trees retain their dried-out leaves over the winter. These dried out leaves are referred to as ‘marcescent’ leaves. There are varying opinions as to why this occurs.

Here is what happens.  Early cold Fall weather or frost seems to encourage some trees to hold onto their dried-out Fall leaves. For some trees, especially certain Oaks, clients mention that a particular tree seems to experience this every year.

For most trees, cells release enzymes that unglue the leaf from the tree in the Fall allowing them to fall to the ground. But early cold or frost can interfere with the process on these previously mentioned varieties of trees. Marcescent leaves are more common on smaller trees or on the lower branches of larger trees.

Some believe that this process occurs with trees that are lacking proper nutrients. But we at Tree Green do not believe this to be the case. Why? Because we have clients whose trees we have been feeding every year for 20 to 35 years still experience this situation. We know that there is no possibility that these trees are lacking nutrients when you consider the suspension of rich minerals, nutrients and amino acids that our root fertilization process provides.

When the new tree buds form and begin to swell in the Spring, they will push off last seasons dried leaves as you have experienced in the past.  Until that process occurs don’t worry about your tree at all. Just enjoy those rustling brown leaves that seem to be ‘waving’ to us throughout the Winter.

A Rough Spring Ahead?

We’ve recently noticed that certain types of flowering trees and shrubs have their 2016 flower buds swelling, and in a few instances, actually opening this December! Why? The trees are confused.

The abnormally warm November and December is tricking certain Magnolia, Crab Apple and potentially other plants into thinking they should be flowering. We’ve seen this happen before. What may unfortunately occur is this…

When the flower buds are tricked into swelling ahead of schedule, whether they actually open into flowers or not, they may be damaged by the inevitable cold winter which will surely follow. It may not be as cold as usual due to El Nino, but it will be cold enough to burn and dry out the buds. This means that your tree may not flower at all in 2016, or the flowering may be sparse or weak.

We already know that we will be receiving calls next spring where the messages will be as follows….

”You sprayed our tree last year and now it won’t flower”. Rest assured that if this happens to your tree, it has nothing to do with any applications. Mother Nature is the guilty party.

This situation can also occur when we have an unusually warm January or February. Those flower buds swell early, and then if we get night time freezing temperatures in March, ‘Winter Burn‘ sets in and the buds suffer from the same negative effect.

A lot will depend on the exact varieties of trees that are involved within each species, not to mention things like soil moisture as well as directional exposure in relation to your house or other mature plantings, which may or may not protect them from cold winter winds. Only time will tell as to whether or not your trees will be affected next spring.