Tree Maackia amurensis [sold as Summertime™] [Summertime Amur Maackia] The Summertime Amur Maackia is a small tree with low branches, attractive mottled bark, and upright, creamy flower racemes that appear in the summer. This tree, closely related to Cladrastis kentukea (American Yellowwood), is an adaptable plant that is able to fix atmospheric nitrogen.