Leaf Size Helps Determine Light Penetration
If you want to plant a tree on your property, but don’t want to give up a sunny flower bed or lawn because of the shade the tree will create, consider the following detail: the smaller tree’s leaves, the more light will filter through; the bigger they are, the less sun reaches the ground. So trees with tiny leaves or deeply cut leaves, like honey locust (Gleditsia spp.), black locust (Robinia spp.), silk tree (Albizia julibrissin) or cut-leaved alder (Alnus glutinosa ‘Imperialis’), let in lots of light and you can consider the space at their feet as being in full sun. Other trees have very large leaves and create deep shade, including Norway maple (Acer platanoides), sugar maple (Acer saccharum), basswood (Tilia americana) and red oak (Quercus rubra). It is difficult to grow flowers or lawns at their feet. Most other trees have an “average-sized” foliage and will give medium shade, what gardeners know as partial shade.