Hail Damage
Click for larger image Hail can cause damage throughout the landscape

Hail can severely damage all plants. The severity of the damage depends on the size of the hailstones and the time of the year that the hailstorm occurs. The later in the growing season that hail damage occurs the less time plants have to recover and store energy for the winter.

Symptoms and Diagnosis

On annuals and perennials leaves, stems and flowers may be shredded, torn and knocked off. On trees and shrubs leaves, twigs and branches may be tattered, split and broken. Fruit may be pitted and knocked to the ground. The scars from hail damage to trees occur on the upper side of branches and on the side of the trunk facing the storm. The tree may take a very long time to recover. The damage increases the vulnerability of the tree to decay causing fungi and insect activity.

Integrated Pest Management Strategies

1. Evaluate damage. Assess the damage to the plants and estimate how long they have left to recover from the damage before the onset of winter.

2. Cleanup. Severely damaged trees and shrubs with broken branches should have them removed promptly. Less severe wounds may slowly heal naturally over a period of time. Damaged fruit should be removed. Do not fertilize hail damaged trees.

3. Fertilize. If the damage is early in the growing season, annuals and perennials may benefit from a light application of fertilizer. Immediately remove any damaged leaves from these plants.

4. Replace. Annuals and perennials that do not show signs of recovery within a week should be replaced with new plants.

5. Give good after care. Water the damaged plants during the growing season giving them at least one inch of water each week.

6. Mulch. Applying two to three inches of mulch around the base of damaged plants may help them survive during the winter.

Organic Strategies

Strategies 1, 2, 4, 5, and 6 are strictly organic approaches. Using an appropriate organic fertilizer would be a viable organic approach to Strategy 3.

More images:

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Trees and shrubs callous over hail damage
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Scars from hail damage on a twig
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Hail damage on red horse chestnut (Aesculus pavia)
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Fresh hail damage on hosta (Hosta)
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Hail damage on geraniums (Pelargonium)
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Cicada damage and hail damage look similar, but cicada damage is on the underside of twigs, while hail damage is on the upper surface; this is cicada damage on oak (Quercus).
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