Dewberry canes flower and develop fruit in their second year. The first year only produces leaves. New shoots emerge from the plant's crown each spring and grow into trailing canes. In the summer, these new canes develop lateral branches and buds that flower and fruit the following year before dying back. If well tended, dewberry brambles produce for fruit for 6 to 8 years or more.
Dewberry canes flower and develop fruit slightly earlier than other blackberry species. This can range from flowering in the early spring through to early May. Depending on the climate and growing conditions, the fruit ripens and is ready for harvest from very late May to early June and into August. Dewberries growing warmer and temperate climates flower and fruit early.
Dewberries are green when nascent and turn dark, reddish black as they mature. The berries are ripe for harvest when deep purple-blue black and are swollen and glossy but still firm. When ripe, the individual berry releases easily from the stem when gently plucked.
Once the dewberries darken to near black and swell, they rapidly age on the canes. Harsh, direct sun and moisture speed this process. When the berries lose their firmness and become soft or mushy in places, they are past their prime for fresh eating, freezing or preserving. Leave them on the canes as forage for local wildlife. Dewberries are a food source for birds and small mammals.