I have a forest flame in a quite large pot, but after about 6 years, it seems to be struggling. It has grown to about 3 foot dia and height. The question is, does it need re-planting in the garden, or can I prune it back fairly heavily, and give it a new start, I look forward to an answer as it has been a real eye catcher until this year
If I were you I would plant it out into the garden. Not many plants enjoy being in a container though some can tolerate it but once the roots have no place to go they struggle. You could always plant it into a bigger container and keep it there for a couple of years.
i think forest flames need a slightly acidic soil like azaleas do, ive never been able to grow them in my garden, they always die out.
you could transfer it to a larger pot, or it could be the compost it is growing in is spent and it needs some fresh compost and/or a good fertilising/feeding.
and this is probably not the best time of year to be re-planting a pot plant into the garden, you'd be better off waiting to the autumn when the weathers wetter and cooler.