Planted Hydrangea macrophylla early summer, was thriving for first 6-8 weeks but now some of the leaves are looking burnt and a bit dried out, but more distressingly all the flowers are fading in colour and turning brown, soil is moist I’m sure it doesn’t need water but I have no idea what is happening to it.
The plant may not have rooted away from the root-ball yet and has not settled in at the root. Therefore its capacity for growth is reduced. Also the plant may be growing in a more exposed position than it was used to, and has taken some hardship, but it will adapt. The flowers are first to go when a plant is struggling, fading and turning brown. Give it a feed of shrub fertiliser in spring.