While Mulberry trees are native to China, they very adaptable and can be found in all kinds of different climate zones, from Mexico to Europe and Canada. They are planted all over the place for decoration, and have been widely naturalized throughout the world.
They turn ripe in June, along with the early raspberries and juneberries. A tree can produce a fairly considerable crop, but you’ll be fighting the birds for your haul. The fruit ripens slowly over the course of weeks, so you’ll be harvesting regularly in moderate amounts for weeks, rather than in one big haul.
The berries essentially look like elongated blackberries. You will notice that there is a small green stem that you can’t pull out of the berry without destroying it. You can either just eat the stem, or you can pinch it off with your fingernails.
You can see in the image that the tree has elongated, waxy, toothed leaves. Combined with the conspicuous berry, it’s an easy tree to identify.