Aspen Struggling - Ask Extension
My aspen’s leaves have black spots and curling. They are also “bleeding” from the trunk.
Knowledgebase
Aspen Struggling #871082
Asked June 01, 2024, 4:36 PM EDT
My aspen’s leaves have black spots and curling. They are also “bleeding” from the trunk.
Larimer County Colorado
Expert Response
Hi Brian,
This looks like one of the many foliar diseases that aspens can get at lower elevations (and even where they grow best, above 8,000 feet). We had periods of wet weather this spring, which likely caused some of the disease pressure. Fortunately, this happens often and doesn't harm the tree (though it looks bad and can cause early leaf drop). Any management needs to be preventative and applied early, around budbreak.
https://extension.colostate.edu/topic-areas/yard-garden/aspen-and-poplar-leaf-spots-2-920/
The "bleeding" might be from another disease, if it's amber/orange color. Cytospora is very common and affects mostly stressed trees. Boost your cultural conditions with regular water, proper pruning, and applying water in fall and winter during dry periods.
This looks like one of the many foliar diseases that aspens can get at lower elevations (and even where they grow best, above 8,000 feet). We had periods of wet weather this spring, which likely caused some of the disease pressure. Fortunately, this happens often and doesn't harm the tree (though it looks bad and can cause early leaf drop). Any management needs to be preventative and applied early, around budbreak.
https://extension.colostate.edu/topic-areas/yard-garden/aspen-and-poplar-leaf-spots-2-920/
The "bleeding" might be from another disease, if it's amber/orange color. Cytospora is very common and affects mostly stressed trees. Boost your cultural conditions with regular water, proper pruning, and applying water in fall and winter during dry periods.
