I think it's just natural aging of the inflorescence. It won't last forever.

Ah, OK thanks for the reply. As long as theres nothing wrong with it that's ok

Thanks!

DaveSk - Those black marks may just remnants of old flowers or perhaps new ones which have died within the bracts. In any case I don't think it's anything to worry about.

You say you water the "heart" (I take it you mean just the central foliage of the plant) once a week "although the soil seems dry. "

It's important you water the potting mix as well and you should give it enough so that it runs right through the mix and out of the drainage hole.

The mix needs to be just damp (NOT WET) and with a bit of experience you will be able to judge by the weight of the pot when it needs watering.

I'm not aware of your climatic conditions so I can't say how often you should water, so best to ask someone locally.

The main thing to remember is DON'T OVER WATER - More plants are lost from over watering than under watering.

Al the best, Nev.