If you are a passionate gardener who monitors the progress of your pride and joys throughout the fall, spring and summer, then you may become concerned if a shrub experiences leaf out problems late in the season or other issues. Such an occurrence may signal a serious issue or it just might mean nothing.
There are a number of reasons why late or delayed leafing may be taking place. For example, temperature and day length can affect the time of the blooming. So you should anticipate a delay
Causes of leafless shrubs or trees include temperature and day length; disease; or insects.
(Courtesy: Eric at Flickr.com)
in a shrub’s leaf out during years when temperatures are cooler and an earlier blooming during warm years. These year-to-year inconsistencies are normal.
In fact, you may notice differences as the shrub matures. Young maples, for example, often sprout leaves before older species in order to absorb energy from the sun before older shrubs bloom and block the sun’s rays. These shrubs will leaf out later as they develop.
Checking the buds or the twigs can determine if more nefarious problems are at play. Remove a bud and open it. If it is green on the outside and brown inside, then that shows that the shrub may be suffering a cold injury. Check further by clipping off the bloom from the twig and strip the bark. The wood you observe under the bark should be soft and green. If the wood is dry and brown, then the shrub could be suffering from chronic stress, which is caused by insects, diseases, and poor placement of the shrub in question. Shrubs planted too close to pavement often experience chronic stress because the soil is too hot and too dry.
You should start to suspect a disease if whole branches or twigs do not leaf out or when there are no leaves on the bush.
If the wood has brown streaks, then the shrub could have verticillium wilt. To treat it, trim back the diseased twigs with a clean pruning shear until you get to healthy wood. Be sure to disinfect the shear between cuts to avoid spreading the illness. If the shrub shows symptoms on most of its branches, then you may not be able to save it.
If the shrub is completely defoliated, then you probably have insect problems. You need to identify the insect that is causing the trouble so that you can use the proper insecticide. If you can’t identify the bug, then consult with the extension service of a nearby university.
Do not use non-specific insecticide on the shrub because you may make the problem worse. First use non-chemical methods to eradicate the insects. If that doesn’t work, then use only the insecticide that kills the bug you want to kill. Carefully follow the instructions. Improper mixing or spraying at the wrong time can cause serious damage to the shrub.
Tar Spots
Small, pale yellow spots on leaves of a tree or shrub indicates tar spots.
(Courtesy: Minnesota Dept. of Natural Resources Archives, Minnesota Dept. of Natural Resources)
Signs of a tar spot fungus infection of a tree commonly occur in the middle of June or mid-July through early August. The leaves will exhibit small, pale yellow spots. The size of the spots increase and the yellow color intensifies as the season advances.
Tar spots don’t threaten the health of the tree. However, as they grow and intensify the appearance of the tree could become unsightly. If the tree is heavily infected, then there could be early shedding of leaves.
The best way to handle this condition is to rake and burn leaves in the fall. This reduces the amount of over winterizing spots, which can cause spores during the coming spring. Experts also suggest that you thin out the leaves of the tree branches to encourage better air flow. You may also have to purchase fungicides to help control the infection. Follow the instructions on the label to assure that you use the substance properly because they can cause damage to some plants.
You may have to apply the fungicide more than once depending on the harshness of the problem.
Think of the treatment of tar spots the same as you do when treating an allergy. It never goes away, but with regular treatment there are fewer symptoms each year.
