Answer: Based on your description (and a peek at the past month's weather for Syracuse) I suspect the cold nights may be delaying the blooms. Mandevilla is a true heat loving plant and objects to temperatures below fifty five degrees, it also needs warm soil temperatures to perform its best. Now that nights are staying in the 60's I would expect them to open. Also, be sure you keep fertilizing regularly with a water soluble or slow release fertilizer with an analysis of 5-10-5 or similar proportions. Finally, be sure to keep the soil evenly moist (damp, not sopping wet) for best results. Enjoy your mandevilla!
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