Spread a 2 or 3 inch layer of some organic material such as chopped leaves, pine needles, wood chips or commercial bark product over the zelkova’s root zone (not against its trunk) out as far as the leaf canopy extends. This year round mulch will help keep the soil moist, protect its tender trunk from injury by mower or trimmer and improve the soil as it continuously decomposes. Expand the circle of mulch as the tree canopy grows wider.
Water only in drought conditions
When the tree has been in place for at least six months, sprinkle some granular slow-acting fertilizer formulated for trees on the mulch for the rain to soak in. Do this annually for 3 or 4years if the tree is in mediocre soil. Eventually the constantly decomposing mulch will improve the soil and the tree will not need regular fertilizing.
Prune young trees to establish a branching framework and remove rubbing branches. Sometimes the narrow angle of the crotches where upright branches attach to trunk causes splitting.