It appears that your tree is suffering from a common fungal disease called horse chestnut leaf blotch. Several of the Garden’s horse chestnuts show signs of this same disease.

Chestnut forests were destroyed by chestnut blight between 1904 and 1950. The genus Aesculus contains 13 to 19 tree species, some erroneously called chestnuts and others called buckeyes.

Horse chestnut (Aesculus hippocastanum) trees are widely planted for their ornamental and wildlife value. Mid-spring, they bloom gorgeous red-flushed white flowers, luring in hummingbirds and bees.

The flowers of the horse chestnut tree are spectacular in the spring. Dozens of tiny white and/or pink florets spike into the air on pyramid-shaped, green stalks known as candles.

Today the invasive horse chestnut (Aesculus hippocastanum) is common enough that it is the first tree that comes to mind when a chestnut tree is mentioned. Its nuts are not edible and are even ...

[2] Chemical composition of horse-chestnut (Aesculus) leaves and their susceptibility to chestnut leaf miner Cameraria ohridella Deschka & Dimić. Acta Physiologiae Plantarum (2017).

A horse chestnut tree, like the one mentioned in "The Diary of Anne Frank," has been planted in Kelly In­gram Park to mark Holocaust Re­membrance.