Why is My Crabapple Dropping its Leaves?
It is likely that the leaf drop is the result of a fungal disease called apple scab. It's more common following cool, wet springs. The leaves develop small purple spots that can become large brown blotches on the individual leaves which are shed from the tree in mid-summer. The disease is seldom harmful to a healthy, established tree. Infected leaves cannot be cured but the initial infection can be prevented by applying a fungicide beginning at bud break. Control requires yearly spraying, which is time consuming and costly.
Unfortunately, many crabapples are worthless because of extreme susceptibility to apple scab. It makes no sense to spray or to have half-to fully-defoliated trees in the garden when smart selections are available. Disease resistance should be your first consideration. The following list has shown good disease resistance to apple scab.
- Adirondack (Malus 'Adirondack')
- Beverly (Malus 'Beverly')
- Calocarpa (Malus x zumi 'Calocarpa')
- Dolgo (Malus 'Dolgo')
- Harvest Gold? (Malus 'Hargozam')
- Lancelot (Malus x 'Lanzam')
- Molten Lava? (Malus 'Molazam')
- Prairifire (Malus 'Prairifire)
- Professor Sprenger (Malus 'Professor Sprenger')
- Royal Raindrops (Malus x 'JFS-KW5')
- Tina (Malus sargentii 'Tina')
- Sugar Tyme? (Malus 'Sutyzam')
This variety was a poor choice in the landscape.
By mid-summer apple scab infection make these trees look sick.
Royal Raindrops crabapple leaf shows no apple scab infection
late into the fall.
For more information on apple scab