Old Crepe Myrtle Trees
I have a row of very old crepe myrtle trees that seldom bloom. They have been pruned many times over the years and it appears down to the main trunk so, they have developed big knots at that place. Do I prune the remaining tall branches back to that point or cut below the knots? We also have one that is at least 80 feet tall and blooms way up at the top.
Certified GKH Gardening Expert
It sounds like it may be a sunlight issue. I would recommend thinning out the interior branches to allow more sunlight to get in. From your description, it sounds like the trees have been pollarded in the past, which normally results in a dense growth of branches from the knots. These branches can block sun from each other and can limit blooming if unthinned. Just to be on the safe side, add some phosphorous to the soil (to encourage blooming) and have the soil tested to make sure the nitrogen levels are not too high.