I hope someone could give me advise, my azalea has been struggling in the last few months, the leaves come out but end up having brown/black tips and dying off- I thought to much water so adjusted and no success so adjusted the other way and same issue really, so maybe it is a root issue question in at this time of year should you repot in new kanuma ?? Or leave it alone or could it be something else thanks for the help (I am in uk)
I would definitely wait to repot until it is healthier. It does look like it could be root rot issues, being in the UK I am not sure what you have for fungicides. I happen to use a product here that is labeled for root rot diseases but technically it is a 0-30-30 fertilizer that is derived from mono and di- potassium salts of phosphorus acid. I live in the southeastern US and we have periods where the disease pressure is great enough that I will treat as a preventative every 21 days. The product is sold under many names Agrofos is one that is available to homeowners here in the states. I also found that my azalea do better with a 80:20 mix kanuma to pumice. Azalea watering can be difficult, as they like moist soil but not wet feet. Also if they ever dry out then it is hard to recover. In the past when I had a plant struggling I would carefully pull the flower buds in the spring to preserve energy. Best of luck!
What is the Ph of your water?
You may want to think about putting the tree in a sawdust bed (see Randy Knight podcast) until you can repot in spring.