Species and hybrids of Hydrangea and other genera such as Schizophragma may spread by suckers or stray seedlings in the garden or persist on old homesites, but it is doubtful whether any are truly escaped or naturalized yet in our area.
1. Pubescence of simple hairs or essentially absent; stamen more than twice as many as the petals (ca. 25–90) or the flowers “double” (the stamens mostly modified into petals).
1. Pubescence stellate; stamens usually 10 (twice as many as the petals).
All species found in Hydrangeaceae
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. March 25, 2019. https://www.michiganflora.net/family.aspx?id=HYDRANGEACEAE.