Answer: Mandevilla is a tropical plant that really likes sun and heat and humidity. It needs full sun all day and warm temperatures, including warm nights, and warm soil, to bloom. In your climate, it may be helpful to place it in a location with reflected heat from a wall or similar spot to help it warm up as early as possible in the season. If it is in a container you might try moving it to a more favorable location. Also, be sure the fertilizer you are using is a complete one such as 10-10-10 plus minors. I hope this helps.
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