Beginner Gardening: My hibiscus flowers curl up, 2 by Anne80

Anne80 wrote:
I have a hibiscut, that I have had for 2 years. Normaly the flowers are fine . But the 4 flowers that are on it now are all curled and twisted.
In spring, the plant came over in a bigger pot and the pot is a self vatering pot. Aprox every 14. day I give the plant some fertilizer.
Does anyone have any idea, why my hibiscus flowers suddenly is curled up. The flowers are newly developed on the plant (they are not withered).
See pictures.