Hawthorn plants grow as small trees or large bushes and are members of the Rosaceae family of plants. Both English and Indian hawthorns bloom in shades of pink. Hawthorns are hardy plants that grow well in a variety of climates and soil types, but several factors can lead to browning of the deciduous foliage, wilting and leaf drop. Proper care can help eliminate this problem and promote healthy growth.
Hawthorn trees are small trees that reach an average height of about 25 feet tall. The leaves on this variety of deciduous tree turn colours in the fall, often resulting in canopies with shades of red, orange and gold. Annual leaf dropping follows the change in colours. Leaves that turn brown and wilt during the active growing season are a sign of an unhealthy condition requiring your attention.
Like other landscaping trees, hawthorn trees are prone to certain pests. The hawthorn lace bug is one of the most common pests in this type of tree, although it feeds on many plants in the same family. This tiny bug sucks the fluids from the top and bottom surfaces of hawthorn leaves. Although the bugs are difficult to see, their damage is usually obvious. The first sign of a hawthorn lace bug infestation appears as yellow spotting on the leaves. As the feeding progresses, the leaves lose most of their colour, turning brown and eventually falling from the tree. Applying an insecticide labelled for use on hawthorn trees quickly can eradicate hawthorn lace bugs and other pests that damage foliage.
Hawthorn leaf blight is a major cause of severe fungal infections that can cause hawthorn trees to wilt and die. Diplocarpon mespili is the fungus responsible for this type of leaf blight. It causes the affected leaves to develop spots in shades of red and brown. The spots spread into large lesions that cause the leaves to lose their green colour and drop from the tree. Dead leaves around the base of hawthorns are the main cause of this disease. Raking up the leaves and keeping the soil around the trees free of vegetative debris will help eliminate this problem. Spraying a pink hawthorn with a fungicide treatment in the spring also will help decrease damage due to hawthorn leaf blight.
Trees that seem to wilt without any sign of pests or disease may be the victims of improper care that leads to stress. These trees require full sunlight to partial shade. Although they tolerate both moist and dry soils, they can suffer during extended droughts. Water a hawthorn deeply and regularly to keep the soil evenly moist near the deepest roots. A fertiliser formulated for deciduous trees can help eliminate nutritional deficiencies that may contribute to overall poor health, including wilting foliage.
- Cornell University: Leaf Blight of Hawthorn
- North Carolina State University: Hawthorn Lace Bug
- Urban Forest Ecosystems Institute: Double Pink English Hawthorne
- "Botanica's Gardening Encyclopedia"; Susan Page; 2001