Q. Mr. Punzi, My pink azaleas are blossoming, but for two years now the white ones don’t bloom. And for years they did. What’s wrong? Thanks, Phil Whittenberg – Lakewood, WA
A. There are many situations that can occur that will prevent azaleas from blooming. The problem can arise from their culture (which you are responsible for) or from their response to the environment. The most common cultural problem, which is responsible for loss of blooms, is inappropriate pruning. Azaleas like all Rhododendrons initiate flowers within a month after blooming. For most varieties this means that next years flowers will be initiated and set by the end of June. Any pruning after this point (including shearing) means loss of flowers. Also “pruning” by deer provides the same results. Also excessive fertilizer (especially Nitrogen) during the flower bud initiating period has been attributed to inhibition of flower bud formation in favor of leaf bud formation. Since you have mentioned that the white azaleas have been blooming for years you should consider if you changed your routine for these plants. Also since your pink azaleas are blooming you should consider what may be different for the two plants. How close are they in the yard? Environmental conditions may be different for the two plants. For instance if the azaleas are in different parts of the yard one plant may be getting less light than the other. If over time canopy trees nearby create more shade the white plants may have simply have not received enough light energy to form blooms the last two years. Or perhaps they are receiving less moisture due to tree canopy (affecting rain water dispersal) or the irrigation pattern of you watering method. I would do a simple soil test since too little nutrients could also be a factor. Also there are things that can happen to the buds even if they do form. Late frosts, or fungal diseases can blast flower buds before they open. Both these could affect one cultivar and not another due to their genetic propensities. Use the process of elimination and you should be able to narrow down the possibilities and take corrective action if appropriate.