By: Teo Spengler
When you notice plants losing leaves unexpectedly, you may worry about pests or diseases. However, the true reasons for early leaf drop can be something else entirely, like the weather. Weather events obviously affect trees and plants in your garden.
Read on for more information about early leaf drop in trees and plants and how it relates to weather in your area.
Plants Losing Leaves
That falling foliage may be weather related rather than something more dire. Your trees and smaller plants all lose leaves at different times and for different reasons. When you see plants losing leaves, the issue can be pests, diseases, or improper cultural care.
Early leaf drop in trees, though, is often weather related. The term ‘weather related leaf drop’ is used to describe how plants react to extreme weather or sudden changes in weather conditions. Very often, they drop their leaves.
Every year is unique when it comes to weather. Some events particularly affect plant life in your backyard. This can include snow, wind, excess rainfall, drought, and unusually warm spring days followed by cold weather. Any or all of these can be reasons for early leaf drop.
Often, the leaves that fall as a result of weather-related leaf drop are older leaves that would have fallen later in the season anyway, were it not for the spell of extreme weather. This is especially true for conifers.
Dealing with Early Leaf Drop in Trees
When early leaf drop is due to recent weather, there is little you can do to help the tree. While this may sound discouraging, it isn’t as bad as it sounds. Most of the time when you see leaf drop because of the weather, it is a temporary defoliation.
The plants will likely recover unharmed. The time to worry is if you see early leaf drop year after year. This can cause stress and make the plants susceptible to pests and diseases.
In that case, you should determine the weather event that is at the heart of the problem and try to compensate for it. For example, you can irrigate during drought or offer protection from cold weather. Alternatively, you might want to swap out your plants for those more adapted to the weather in your area.
This article was last updated on
Read more about Environmental Problems
- Tan to brown irregular shaped spots or blotches on young leaves.
- Infected leaves are often distorted, cupped or curled.
- Severe infection can result in leaf drop in spring. Trees produce a second growth of leaves by midsummer if leaf drop occurs.
- Anthracnose may cause tan to dark brown spots on mature leaves but these leaves do not become cupped or distorted. Leaf spots on mature leaves are often found with minor wounds like insect feeding.
- Leaf symptoms are often most severe on the lower and inner branches of the tree but may progress up through the canopy.
Infections on green twigs are most common on young twigs of oak (Quercus spp.) and ironwood (Ostrya virginiana). These appear as small orange brown blisters or a brown band encircling the young twig resulting in shoot death.
In Minnesota, anthracnose is most common during cool (50 to 68 degrees F), wet spring weather.
Anthracnose can occur in the summer if cool, wet weather happens at the same time as leaf growth.
Trees affected by anthracnose in Minnesota
Anthracnose is caused by several different, but closely related fungi. Most fungi that cause anthracnose can infect only one type of tree. For example, fungi infecting ash trees will not be able to infect maple or oak trees.
- Black walnut
Live Oak Leaf Drop
If you have live oaks in your landscape, your yard may be starting to look like this!
While there are a number of problems that can cause leaf drop in Live Oaks, this time of year you’re most likely seeing a normal senescing, or dying off, of last year’s foliage. As temperatures begin to rise in late January through February, your Live Oaks can begin to look sickly or stressed. Leaves begin to yellow and may have brown or black blotches. They will often discolor very quickly and begin to drop en masse.
To make sure your tree is experiencing normal leaf drop, look closely at the leaves that are discolored: You should see new leaf buds forming at the base of the leaf petiole (stem). If these new leaf buds are present, your tree is experiencing normal leaf drop. If there are no new leaf buds present, your tree could be stressed for another reason. Check some of the stems on lower branches you can reach and bend or snap some small stems. Check that they are green to greenish-white and that they aren’t completely dried out. While some dead stems and branches are normal on trees, more than about 10% die off could signal a larger problem or disease. Oak Wilt can start presenting this time of year so it is best to call an arborist quickly if you suspect the disease.
If your Live Oaks are going through their normal leaf drop cycle, then get out the rake and enjoy the nice spring weather! If you’re concerned your tree may have a problem, give us a call right away and we’ll schedule you for a tree inspection. Drop us a line at [email protected] or call 214.528.2266 in the Dallas area and 817.581.4502 in the Ft. Worth area.
Categories: Trees, Disease
Tags: Disease, Trees
Posted: March 18, 2013
Two pests in particular can cause an orange tree to drop its leaves: scale insects and mites. Scale insects, which look like tiny dots or "scales" attached to the leaves, often infest citrus trees. Citrus rust mites begin to infest in spring when the tree has a flush of growth. While mites are largely innocuous, large infestations can kill an orange tree. Neem oil can treat both pests. Water your orange tree thoroughly the day before treatment. Most neem oils are concentrated and a common dilution rate is 2 to 4 tablespoons in 1 gallon on water. Put the mixture in a garden sprayer and spray both sides of the leaves thoroughly in the early morning. Soak the leaves thoroughly, shaking the solution as you go because it easily separates. Repeat the process every two weeks, at least three times. Once the pests have been eradicated, your orange tree will grow new leaves.