Hardy Rubber Tree (Eucommia ulmoides)&lt;br /&gt;
If you want green leaves on a tree during a severe drought, this is your tree! This little-known but urban-tough, has Elm like ascending branches reaching heights of 40-60 feet and nearly as wide. Attractive rounded habit.  Ideal for use as a specimen, shade or street tree. The thin, glossy, dark green leaves are almost totally resistant to pests and disease and remain an attractive dark green throughout the summer, changing only to a paler green before dropping in early fall. The foliage is quite striking and appears to glimmer in the moonlight or when lit from above.  Only one or two corrective prunings at an early age normally is all that is needed to develop good structure in the crown.   Has medicinal uses too.  Has latex in the sap. Cold hardy to U.S.D.A.  Zone 4.