Tip the telescope in the main cardinal direction (N, S, E, W) at an elevation of at least 30 degrees in the same direction the leaf is stuck. For example, if the N, NW, or NE petals are stuck tip the scope north; if the E petal is stuck tip the scope east; if the W petal is stuck tip the scope west, if the S, SW, or SE petals are stuck tip the scope south. This should allow gravity and the weight of the petal itself to flop open. From there you should be able to close all the way.