Pruning
If you are going to prune bushes it is best to do it straight after flowering. Spring flowering shrubs flower on last years growth so if you prune them in autumn there will be nothing for them to flower on. Autumn flowering shrubs flower on the current years growth so if you prune them in summer, again, there will be nothing for them to flower on.
Keep cutting or deadheading flowers to prolong flowering.
The reason for flowers is to attract insects to enable the plant to make seeds. If you cut the flower before it can make seeds then the plant is encouraged to produce more flowers to make up for the lost ones.
Watering
Only water in very dry weather in the first year if the plants are beginning to look as if they need it. They shouldn’t need much as they’ve been planted in autumn and have had the winter and spring to establish their root systems. Too much watering stops the roots growing deeply to look for water and means they will always need watered. My advice is not too unless really necessary.
Weeds
There shouldn’t be many as we’ve put down weed suppressor and a good thick mulch of bark but if any do come through it is best to get them as soon as possible so they don’t set seed.