The Golden Rain tree (Koelreuteria paniculata) blooms in mid-summer. The yellow conspicuous flowers hang in grape-like clusters over the tree and develop into bright greenish yellow fruit that dries and turns to pink then brown in the fall. The golden rain tree is an attractive small tree up to 30 feet tall and 25 feet wide and is tolerant of a wide range of soil conditions. The golden rain tree is appropriate for USDA zones 5 and warmer. The tree grows best if planted in the early spring as the ground warms. Prune in winter when the tree is dormant.
Prune a young golden rain tree for the health of the tree only and not for shape. A young golden rain tree is naturally thin with uneven growth. The only pruning that should be done is removing the lower limbs that are dead or any limbs that cross other limbs and touch, causing wear on the limbs where they have contact with each other.
Prune an older golden rain tree by removing lower limbs that interfere with access to the lower portion of the tree such as when mowing or cultivating. Cut the lower branches at the branch collar or the thick area where the branch meets the main trunk. Do not cut the branches flush with the tree or right against the trunk because it will delay the healing process and allow damaging insects or disease to enter the tree.
Prune out dead or diseased limbs as the tree gets older as an ongoing maintenance program. The tree naturally develops into a rounded even shape if planted in full sun with plenty of room to spread out. Occasionally, smaller limbs inside the tree canopy will die out and these need to be pruned to give the tree a neat appearance.