I've lived in my house in Newburgh, NY long enough to have seen everything there was to see in my backyard... or so I thought.

This morning I noticed a strange phenomenon on one of our beloved maple trees: what looked like spikes growing out of several leaves (below). Here's what it means if your trees start to sprout "thorns" as well.

Spiky galls on a maple leaf
Have you noticed "spikes" growing out of your maple tree leaves? (TSM Poughkeepsie)
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Growths on New York Trees: Harmless vs. Dangerous

Growths on plant leaves can range from completely harmless to dangerous. Cedar apple rust, for example (also known as "exploding hearts", below), grows on cedar trees but can be devastating for nearby apple trees. Luckily, the "spikes" on maple leaves are something completely different.

Photo of a cedar apple rust gall on a tree
Cedar apple rust grows on cedar and juniper trees before it releases spores that seek out host apple trees (TSM Poughkeepsie)
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Maple Spindle Gall Mites in New York

The growths on my maple tree are classified as "galls", and like grape tube galls and oak leaf midge galls, the spikes on the maple leaves are actually homes for tiny animals, specifically maple spindle gall mites. Here's what it means for your tree:

Photo of a maple leaf hosting maple spindle gall mites
If you notice "spikes" on your sugar maple leaves, it is most likely caused by maple spindle gall mites (TSM Poughkeepsie)
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The good news, according to the Penn State University extension, is that maple spindle gall mites are generally harmless to your maple tree. While over-infestations may cover so many leaves that it begins to interfere with the tree's photosynthesis process, maple spindle galls on select leaves should not pose a threat.

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While I dodged a bullet with the gall mites, it's always a good idea to monitor changes in your plants and trees. From invasive animals looking to make a meal of your garden to trees that look beautiful but are harmful to the ecosystem, owning property can be a full-time job. Take a look at some invasive plants to watch out for below.

New York State's Invasive Plants To Be On The Lookout For

These seven invasive plants have become a nuisance to the wildlife and people living in New York State. Learn more about them and how to remove them at the New York State Department of Environmental Conservation here.

5 of New York's Most Devastating Invasive Species

Here are 5 species that have invaded New York State and in some cases they must be killed. We are talking about fish that walk on land, plants that cause severe burns and insects that could wipe out a variety of crops that we rely on.

Keep an eye out for these species and you hike, work around the yard or do some fishing this year. Should you locate any of these it is important to report where and when you found them to the New York State DEC.

Gallery Credit: Karolyi

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