Reply #1: It sounds like they're growing properly.

[Gormy Cuss]

Remember that the chokes are flower buds. Give the plants a dose of a flowering plant fertilizer if they don't form buds on their own. The normal progression is that the central stock will send up a bud, then smaller buds will form on the side shoots.

Can't help you with the rain except to say that in my climate they get most of their water in our winter rainy season and grow accordingly. By the time they bud our rainy season is just about over.
My plants are usually 4 ft tall before they bud but they're perennial here, not annual. You may see buds sooner.