Answer: Zinnia blooms do begin small and expand to their full size. My 'Cut and Come Again' blooms are about 2 1/2 inches across when full sized. Watch your plants and let us know if they don't turn out as you expected. I think they'll be fine. This variety really does well in Texas.
The white spots may be powdery mildew, or the beginning of a bacterial spot. Powdery mildew appears as white patches on the upper surface of the leaf. Bacterial spot appears as creamy white areas in the leaf that soon turn black and angular. Control for these two is very different. If the problem continues submit another question with a detailed description of the spot and where on the plant and leaf it appears and we'll be happy to offer suggestions for control.
In the meantime, minimize overhead watering as this can increase some fungal and bacterial disease problems.
Q&A Library Searching Tips