Looks like it did what cauliflower does -- forms a little head that is now "ricey" and overmature. It might or might not have had a happier ending if you had blanched the head as soon as you saw it starting to form. The plant looks great.

1. You let let it get way too old. 2. While in your climate you may be able to get with away with self wrapping types, heads exposed to sunlight will turn pink to purple when exposed to sun. Cauliflower has a short harvest window. The heads should be good if promptly harvested. If they turn overly quick perhaps you should tie up the heads to keep the sun from reaching them.

People are supposed to get their vitamins from their food; plants get theirs from the soil. Neither should depend on supplements. A plant should be able to live under local conditions. Fortunately, roses have lived all over the world all by themselves without soil ammendments, fertilzers, bone meal, phosphates, etc. Their mid-range Ph tells you they are more generalized than specialized. They won't survive in all environments, but in most, and some classes do better or worse here or there (see the discussion on killing Bourbons in Maryland in the Antique Roses forum). You should never add supplements until you have had your soil analized. 'Kill' is the important part of 'overkill.' If you have had your soil analized or the plant is showing specific symptoms of a nutrient failure, supplement that one thing. If the plant has been under stress or neglect, supplements are the equivalent of taking vitamins when you're ill. I Super-Thrive new plants and transplants and give them a good starter soil and I dig in an all-purpose organic fertilzer twice a year--plant feast days (feasting is an important part of balancing a diet; nature provides 'feasts' which we generally do not allow in our gardens). Otherwise, if a plant can't live off the local mother earth, s/he needs a new home.

Your ph is a little high and the roses may be re-acting to it as this can cause what looks like to me as a mild manganese deficiency starting. If it is, the leaves will go to a brighter yellow. I would give the roses a rest from any spray or fertilizer. Just water and see if the new leaves are normal looking. If they do go yellow then there is a foliar spray for mineral deficiencies. Don't give up on the roses as there is always some thing you can do to solve most basic rose problems.