The mountain ash trees here in Revelstoke have not flowered and produced new berries this year. Rather, last year's berry clusters are shrivelled and black and are still hanging. Any ideas?
Having a large crop of seeds every-other-year is common situation in lots of trees/shrubs. The flower buds for the next season are grown after a seed crop is matured. The yearly cycle is approximately this: Inflate buds for leaves and flowers; set seed; mature seed, second flush of leaves; grow buds for next year; rest. Repeat next year, ad infinitum. If some condition interferes with that process, for example if the season is too short for that cultivar to both ripen the seed crop and then grow flower buds for next year, the following spring will have none or few flowers. Having no flowers means no seeds to ripen so the year following will have a bumper crop. A late frost that kills the flowers also means plenty of time to make buds for next year. A bumper crop will take the plant even longer to ripen the seeds, so the next season will have none, again, and so on and so forth: bumper, none, bumper, none, ad infinitum. This is real common with homeowner untended fruit trees and many Azalea that are grown a couple zones north of their native (longer growing season) range. Seeds on your Mountain Ash that overwintered probably means none next year. And so forth.
Well, it's odd that the birds didn't clear off last year's fruit. These look like European mountain-ash or rowan to me, the non-native Sorbus aucuparia -- more leaflets and tree-like.
Yes: the native Sorbus species are consistently low-forking and shrubby, with the naturalized and conspicuous S. aucuparia repeatedly assumed to be one of them. Merely because of geographic location. Similarly Viburnum opulus gets mistakenly called V. edule in this region and propagations of Rhododendron ponticum lingering at the former site of a habitation in the Seattle area got put on the wholesale market here as R. macrophyllum.
I have the exact same problem. How did this resolve? It is September now, so leaves are starting to turn yellow, but otherwise the trees seem healthy. Very worried though. P.S. I am in Cochrane, AB.
If the species seeds out in Alberta as much as it does farther west I wouldn't worry too much. In fact, it may be becoming time for removals instead of seeing individual specimens as delicate or rare treasures. Washington State Noxious Weed Control Board
