Hydrangeas do not need that much fertilizer, Cagey59. One fertilizer application in June will do fine for the whole year where you live. It is possible that Rapid Gro has increased the amount of nitrogen a tad too much and is keeping the second shrub in growth mode. Lawn fertilizers like Rapid Gro tend to do that.
Before trying to move it, I would try to keep soil nitrogen levels lower by using another fertilizer on the hydrangeas and applying it only once a year in June. Also, feel free to apply "weak" fertilizers like coffee grounds during the growing seasons but only thru the end of July. Applying them by that time makes sure that the plant will go dormant as scheduled in the Fall and that early frosts will not zap any new growth. As alternate fertilizers, you can try compost, composted manure or cottonseed meal; a general-purpose slow-release fertilizer like Osmocote can also be used.
While sun exposure might cause a hydrangea not to bloom, it would have to be in dense shade for it not to bloom. My sister had a neighbor who grew a mophead on the front lawn such that it got sun early in the morning and very little sun afterwards... and yet it was always blooming well. Surprised me every time I saw that!
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