To be a hipster, you're going to have to be a little backward. Let me explain. Normally, you should be deadheading spent blooms on your roses to encourage your plants to keep growing and blooming throughout the Summer and into Fall. If you want hips that contain viable seeds, however, you'll need to let hips develop and remain on the bush until they get nice and mature. Here is my backward scheme --
Here in Salem, I leave blooms alone until the end of July, maybe gently plucking off unsightly petals (but no more than that). Remember, I let nature take its course, and depend on open ( or self) pollination. This allows about 1½ months of blooms to develop hips (middle of June through the end of July). Beginning in August, I deadhead all the NEW blooms after they are spent, leaving the earlier hips alone (they should resemble hips by then). I harvest the hips at the end of November, or before the first hard freeze (under 25 degrees). This guarantees that the hips have aged for at least 4 months, namely August through November. Hips on various rose types do not necessarily turn a rich orange or reddish color when they mature. Hips on my 'Queen Elizabeth' and 'Voodoo' roses turn a very slight shade of orange. So, the above method avoids any confusion concerning older and newer hips because there are NO newer hips. As a matter of fact, the strong 'Queen Elizabeth' rose will continue blooming very nicely even while still retaining its early hips. You didn't realize you were a hipster, did you?
I should add that here in the central Willamette Valley, the month of November does just fine for getting the seeds "stratified" as the hips are ripening on the bush. If you live in a warmer region of the world, you will probably need to refrigerate your hips/seeds for a month or so.
