Dead lilac tree
Last year my lilac tree seemed to be dying. We cut off the dead bit and the other part flowered, though not as well as in past years. Gradually the leaves browned off and the rest of the tree died off. We cut it sown on the weekend. One stump was easily pulled out of the ground and I have attached photographs of the cut bit where it seems to be diseased.
A rose growing near it also died. Do we need to dig out the rest of the stump?
Should we decontaminate the ground around the tree before planting anything else? Any suggestions gratefully received. Thanks