Spring 2014 - Flowering Crabapples
By: Anthony Arnoldi, Board Certified Master Arborist WI-0102B
Everyone is familiar with the gorgeous display crabapples have with their overwhelming production of flowers in spring – what can warm us up after a long, long, winter better than these? I think we deserve this to look forward to after shoveling a hundred times and constantly freeing up our cars from winter’s icy grip!
Crabapples should be beautiful even after they flower. They contribute interesting form and branch architecture, pleasing shades of green or colored foliage, fruit displays, and often fall color to the landscape. They frequently fill spaces in our gardens that uniquely suit crabapples. However, many types of crabapples begin to lose their beauty soon after flowering. The spores of a fungus called apple scab infect the leaves as they are unfurling. The spores are carried long distances by the wind. Once the spores successfully infect the leaves, the fungus grows into olive-drab spots that feed parasitically on the tree’s energy. After the fungal spots have caused enough damage, the weakened leaves turn yellow and fall off the tree. The resultant defoliation starts out as a trickle of falling leaves, but later increases and can cause complete denuding of the branches by mid to late summer. The constant mess and unsightliness has caused many a crabapple to be removed!
Weather plays a huge part in all this too. Wet weather as the leaves are unfurling and expanding will enable many more spores to successfully stick to the leaf, making for many more fungus leaf spots. Dry weather during this time limits the number of leaf spots and falling leaves. Apple scab can be seen every year to some degree, however.
The good news is that a spray program of specific fungicides applied in a timely manner will control this disease by protecting the leaves and blocking most of the infection. Timely is a most important aspect of the program. Being early enough to properly coat the leaves before infection can begin is paramount to the best control. For this reason, placing orders for this spray program must be early – the earlier the better for inclusion in the proper routing of the spray trucks.
There are other, similar fungus diseases on other trees such as Rust on Hawthornes, Tar Spot on maples, Anthracnose on oaks and other trees, etc. Although the spray timings for these other diseases are different, they all are similar in that they begin early and need to start before infection begins.
The take-home message here is: return your Spring Tree Care Prescriptions early. In this way, we can prove that enjoying crabapples can be a year-long experience! This has been one of our most popular treatment programs over the years due to its dramatic results. Trees that are protected benefit from increased health and a better ability to deal with any other potential stress that may come their way because of the savings in energy. Call today to have your Certified Arborist renew this service for you or explain how it could add a “wow” to your landscape!