Turning to Lilac

I love the graduating colours of this plant. So very pretty. I used to have two of them in pots either side of my front door, but one of them got diseased and so I moved them both into a semi shady border in the back garden. This is a picture of the healthy plant which seems to be thriving in its new spot. The not so healthy one has been pruned hard, it's flowered but not as beautifully.