 Gardens in the upper park area include Longfellow Gardens , Minnehaha Falls Pergola Garden , and the Song of Hiawatha Garden . The lower glen area offers examples of a surprisingly large number of trees that are native to Minnesota including basswood , black ash , maples , oaks , willows , and cottonwoods . Unusual plants include the first spring @-@ blooming plant , skunk cabbage , often blooming so early that temperatures are still freezing and snow may still be on the ground . As the name implies , they have a disagreeable odor except to the various insects that prefer to feed on rotting flesh or dung . By consuming carbohydrates stored in its fleshy roots , skunk cabbages can maintain a temperature inside the spathe that is 15 – 35 degrees warmer than the surrounding air temperature . The warmth helps attract cold @-@ blooded , early @-@ emerging pollinating insects during early spring when temperatures are still chilly . As the spathe dies back the large , showy leaves emerge which die back by mid @-@ August , making the plant difficult to find in late summer . Other wild flowers include wild ginger , trout lilies , anemones , marsh marigold and various ferns and sedges . The Minneapolis Park and Recreation Board is working to remove invasive species that have been introduced into the park in order to promote a healthy environment so that native species may survive and grow . 
