I think we're on the same schedule Buds. I gave them a feed of potash bout 3 weeks ago. Had a look at them this morning (HEY! It's not been raining!!) and I reckon that they might, just might, be wanting to throw up seed heads soon cos it's now quite humid, so I'll be looking out for that, and nipping them in the bud - so to speak ;D One isn't supposed to water from the beginning of June - but tell that to Imself :( Like OB said, tho, wait for the yellowing/dying back - I'm reckoning back-end of June for mine.
Cheers!