On the eastern side of the Systematic Beds two representatives of the Pea family provide spectacular, if unpredictable, summer flowering. These are the Chinese Yellowwood, Cladrastis sinensis, and its American cousin, Cladrastis kentukea.

In both species, the leaves are made up of many leaflets and create a dense cover against which the long racemes of Wisteria-like, fragrant white flowers flutter in the lightest breeze. Flowering is most profuse after hot dry summers, like that of 2006, when temperatures frequently reached 35°C.

These conditions are closer to those in their native habitats and encouraged the formation of flower buds. In the autumn, the foliage of both species turns yellow, gold, and orange.