Browning Leaves on flowering crab - Ask Extension
We have a red jewel flowering crab apple that has leaves starting to brown and curl at their edges. I realize some of what we see are the spent bloss...
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Browning Leaves on flowering crab #930088
Asked April 29, 2026, 6:55 PM EDT
We have a red jewel flowering crab apple that has leaves starting to brown and curl at their edges. I realize some of what we see are the spent blossoms, but there are still a number of leaves that do not look healthy. It was looking very healthy until it finished blooming. I had been watering it on occasion, but I am concerned it is something more than watering. As a side note, it was pruned in February.
Boulder County Colorado
Expert Response
Hi Robert,
From your photos it appears to be a bacteria such as fire blight but to be sure you are welcome to bring in a sample to the Extension Office in Longmont M-F 8-4:00 for a diagnostician to look closer. The browning curling leaves and irregular patterns are indicative but not conclusive via email.
If it is fire blight it can be addressed by pruning and dipping the pruners into a bucket of weak bleach and water solution to prevent spreading it, bagging up affected cuttings and cleaning up any on the ground near the tree.
Deep watering at the drip line promotes best hydration over shallow watering or close to the tree trunk.
From your photos it appears to be a bacteria such as fire blight but to be sure you are welcome to bring in a sample to the Extension Office in Longmont M-F 8-4:00 for a diagnostician to look closer. The browning curling leaves and irregular patterns are indicative but not conclusive via email.
If it is fire blight it can be addressed by pruning and dipping the pruners into a bucket of weak bleach and water solution to prevent spreading it, bagging up affected cuttings and cleaning up any on the ground near the tree.
Deep watering at the drip line promotes best hydration over shallow watering or close to the tree trunk.
We have a red jewel flowering crab apple that has leaves starting to brown and curl at their edges. I realize some of what we see are the spent blossoms, but there are still a number of leaves that do not look healthy. It was looking very healthy until it finished blooming. I had been watering it on occasion, but I am concerned it is something more than watering. As a side note, it was pruned in February.
