Just Arrived: Surprising Leaf Growths. Here’s What they Mean

Autumn in the Hudson Valley is meant for looking at beautiful foliage while eating the best apple cider donuts in the country. New growths on New York leaves, however, is enough to make you lose your appetite. Here's what they are and what they mean for our trees.

Leaf Gall in the Hudson Valley, NY

This wouldn't be the first time beautiful plants were marred by odd growths in the Hudson Valley. Earlier this year, we were visited by a creature that created peculiar "spikes" on grape vine leaves (above). Called "grape tube galls", the spikes act as a home for small maggots that eventually mature into gall gnats (below). Something similar is happening to our oak trees.

Oak Leaf Gall in New York

Apparently, there are almost as many types of galls as there are leaves to house them. The New York State Department of Environmental Conservation (NYSDEC) recently took to Facebook to explain the growths they described as looking like mini loaves of bread.

"Homes come in all shapes and sizes", their post began. The photo they shared of an oak tree leaf (above) had what they suspected were oak leaf midge galls. Instead of the gall gnats that were living inside the grape leaf spikes, these galls likely house midge flies. The fascinating thing is how they are created in the first place.

How Leaf Galls are Formed

"The midges bite and release a chemical into the leaf that irritates it and causes it to swell up", the DEC explained. "The midge will then burrow into the gall for shelter as it feeds on the leaf". Sounds gross (and looks gross), but luckily, it doesn't spell doom for the tree.

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While the leaves may look like mutants, the overall health of oaks with midge galls is not negatively affected. In addition to grape tube and oak leaf galls, there are also woolly oak gall, ash flower gall, and more. You can report your own gall sightings here.