I have a three-year-old Viburnum growing in a pot that is trying to bloom now. I'm unsure if this is due to wonky weather, since it hasn't been that warm, though it has been bitterly cold the last four days, and will likely warm up to 40-degree weather later this week. It usually blooms in early Spring. Can I send it back to sleep to ensure a Spring bloom, or would it be best to just let it be? Thanks and Happy Holidays!
Viburnum blooming NOW?
I would let is be, allow the flowering BUT place in a sheltered area where it may NOT get frost damage on the buds, the reason for protection is, when the buds get frost damage, it can kill off the buds tissue and this CAN lead to further damage entering the spores where the buds died off.
It might well be that no damage will be done or maybe just a few flowers die off, but you are correct when you say the weather has created lot's of problems for seasonal flowering shrubs / plant as the climate has rather gone hot, cold, sunny and dull all out of time clock and with how we normally know our seasons, I have Rhododendrons flowering all out of normal times BUT maybe the next spring they wont give too many flowers as they have used lots more energy making flowers without a resting period. but I know they will over time go back to their normal seasonal flowerings.
Hope you understand all this but, I don't think you have too much to worry about.
Good luck and Best regards.
Your plant looks like the one I know as Viburnum ×bodnantense 'Dawn'.
This plant is well-known to throw occasional blooms all winter. I have grown this selection for nearly 20 years, and it has never confined itself to spring bloom. This behavior has not affected the plants I grow here at the Valley negatively in the least, insofar as overall health.
If you want to try to prevent the plant from blooming or growing "out of season", then you ought to place it in a position where it will stay as cool as possible. One way of doing that is by not having its roots above ground or exposed to warm winter sun/temperatures.
Sink that pot in the ground in a cooler shadier place, and you will likely see a cessation of advanced growth and flowering. Leaving the pot out where it will warm with the ambient air temperature will almost guarantee this kind of behavior.