Freshening old 'Indigo Spires'
We have 2 old (several years old) S. 'Indigo Spires' which have grown very woody at the base over the years. They got out of hand this year while I tended to other things. The thick woody base spreads laterally in all directions, with the new growth on top. New foliage and blooms appear healthy. Both grow in full sun, clay soil, and moderate/occasional water.
I have cut them back to the new growth on top of the woody base, and am thinking of giving them a good deep watering and spreading fresh homemade compost around them to see if they freshen up. Is this the type of treatment it needs to look its best each year? Does it need more regular water, more frequent trimming, or is it time to replace it?