Tree Sorbus alnifolia [Korean Mountainash] Sorbus alnifolia is an attractive small, dense tree that produces beautiful clusters of white flowers in the spring. In the wild, this plant lives in cooler, mountain climates and is not well-adapted to USDA zone 8 and south. Intolerant of city conditions. Tends to flowers heavier every other year. Susceptible to fireblight and scab, but resistant to borers that frequently attack other Sorbus. Although this plant is commonly referred to as a "mountainash", it is…
Tree Sorbus intermedia [Mountainash] Structural pruning is important for this species, as it has weak crotch angles. Prune so that the trunk and branches cannot rub against each other. This tree does not tolerate competition well and should be mulched to the dripline.