Elderberry is another ubiquitous plant, found throughout Florida and everywhere in the U.S. except the extreme Northwest. It is a shrubby tree that tops out at about 10 feet. It produces clusters of small, white flowers that turn into clusters of blue-black berries. It flowers year round, peaking spring to fall; the berries are food for a host of birds, squirrels and other animals. The clusters are so numerous at times, they can cover the entire plant and making a rather spectacular display. The University of Florida’s Center for Aquatic and Invasive Plants warns that elderberry eaten raw is toxic, although edible when cooked — we've had elderberry jelly many years ago. The raw berries contain alkaloids and don't taste very good; cooking destroys the alkaloids and improves the taste. The berries are high in Vitamin C and there are those who say they have antiviral properties. Native Americans used elderberry for both food and for medicines.

http://www.wildsouthflorida.com/elderberry.html