We are noticing a lot of Winter Burn or Winter Injury to a variety of trees and shrubs. Winter Burn develops when the weather is unusually warm during the Winter months as it certainly was in February. When it is that warm, trees begin to come out of winter dormancy and their buds start to swell and grow. Then, when the temperatures drop back below freezing in March and early April the buds become dried out and damaged when the leaf tissue re-freezes. The damage can become more pronounced as the Spring progresses. The leaves can look droopy and wilted or have brown edges or ‘dead spots’ in the middle of the leaf as shown in the photo.
It is important to note that this is NOT early stage Apple Scab Fungus, Cedar Apple Rust or Tar Spot. There is nothing that can be done or could have been done to avoid this situation.
LEAVES OR NEEDLES ON CONIFERS OR EVERGREEN TYPE TREES
We are also noticing browning on evergreens such as Hemlock, Juniper, Pine and Yews and broadleaf evergreens such as Rhododendron and Boxwoods. Browning usually occurs from the needle tip on downward. On these types of plants, the damage is attributed to what is referred to as desiccation or water loss due to transpiration. Winter sun and freezing winds dry out needles or leaves that remain on the plant all Winter. The way to minimize this type of damage is to thoroughly water plants that are susceptible to this problem on your property in the late fall up until the time that the ground freezes.
The green leaves laying on the ground in the below picture are from an Ash tree that was photographed on May 15th. This is due to a fungal condition called Anthracnose. The wetter the Spring, the greater the possibility of Anthracnose attacking certain trees. We see it most often on Ash, Maple and Sycamore in our area.
On Ash trees, the fungus attacks the stem causing green, seemingly healthy leaves to fall to the ground. An Ash tree can lose up to 75% of its leaves when it is hit with the Anthracnose fungus but the tree will regenerate a second crop of leaves usually in June.
On Maple trees, the leaves curl and wilt and it’s often difficult to tell if the damage is from Anthracnose or Winter Burn.
On Sycamore trees, one of two things typically happen – either the tree leafs out normally and then its leaves fall to the ground like the Ash trees do or the fungus attacks the buds and the tree doesn’t open its initial crop of leaves until mid-June. Quite often, homeowners will think their tree is dead and hire a tree removal company to have it removed. If the tree company is not familiar with Anthracnose, they will remove the tree not realizing it is still alive. If they are unscrupulous, they will be out to remove it quickly before its leaves open. Unfortunately, we have seen this happen before.
Sycamores with this condition will, almost 100% of the time, sport a crop of leaves at the very top of the tree while the rest of the tree will be barren of leaves. If you see healthy green leaves up in the top 2% of the trees canopy, the tree is still alive.
We do not offer treatment to prevent Anthracnose for a variety of reasons but mostly because it is ‘hit or miss’ as to what years it will show up and affect your trees.
As long as you are having Tree Green root feeding your trees, they will be strong enough to survive these conditions.
Have a great Spring!