I have always had a Mandevilla on my patio and have not had any issues with them blooming!
The last 2 summers, my vine has produced many buds that will not open! I have read the previous answer to this question, however, I'm fairly certain, this does not apply to my vine.
I assure you, the photo buds will not open as they have looked this way now for weeks!
I would have to say, "yes". It's on my patio. I have never had an issue with blooming and I have had a Mandelvilla in this location every summer for the last 10 or more years.
Cmsharpe said: I would have to say, "yes". It's on my patio. I have never had an issue with blooming and I have had a Mandelvilla in this location every summer for the last 10 or more years.
Its called Flower balling.
Its a disorder caused by cool, wet weather saturating the outer petals and then sunshine dries and fuses them into a tight shell preventing the bud from opening.
Solutions
good air circulation, increase ventilation by pruning, water plants in the evening around the base rather than over the plant, may need to protect from rain by sheltering somehow, remove balled buds to prevent grey mould.
There really arent any chemicals you can use to prevent this.
Your plant looks green and healthy otherwise.
