Root of the Problem
After several years of growing season drought, we finally had spring rains. In fact, we had summer rains as well with a record breaking 17 inches in June! While the rains provide a great potential for root recovery, (a percentage of tree roots die each year that we have drought during the growing season), too much rain causes fungus problems. Fungus attacks the small tender leaves of early spring. The symptoms show up later however, when the damage is done.
Fungus symptoms include anthracnose, leaf blotch, powdery mildew and mottling of the leaves. Mottling of the leaves is a breakdown of the chlorophyll, the food producing mechanism which goes down in to the root system to promote root growth and food storage for next year. With less chlorophyll, there is less chance of root recovery and root growth. In addition, fungus symptoms can inhibit leaf and flower bud set up for next year.
The Truth about Nitrogen
While the extreme weather conditions can be very hard on your trees and shrubs, you can help your plants recover from past drought or fungus symptoms with a liquid organic fertilizer in the summer or fall. It is important NOT to use a nitrogen based fertilizer. Nitrogen is not a food, but a catalyst which releases stored food. Plants, in time of stress, need a liquid organic fertilizer designed to stimulate root recovery, to create optimal growth conditions and augment the plant’s natural resistance to environmental stress, disease and insects. A liquid organic fertilizer is a blend of humic acid, enzymes, bacteria, growth auxins, vitamins and minerals – a real boost for your plants!
While many of our trees and shrubs show signs of fungus symptoms from too much rain, window boxes and container plants generally were not seriously affected by the rains. Continue watering them daily and fertilize once every other week. In contrast to the liquid organic fertilizer needed for your trees and shrubs, a low nitrogen fertilizer, 5-10-5 or 10-10-10, is fine for your annuals to keep them blooming.
Despite June’s torrential rains, if summer continues to be hot and dry, trees should be watered once every 10 days in July and August. A slow trickle drip with a hose, ideally located at the feeder roots (feeder roots are in the outer third of the drip edge), for four to six hours is recommended. Because most city trees are surrounded by pavement however, getting at the feeder roots is usually not possible. Watering near the exposed trunk may be the only option and is certainly better than nothing.
Coping with Mother Nature’s fickle character can be stressful on trees and shrubs, but we can keep our plants thriving with a little tender loving care.