One of the unique talents of the crape myrtle, besides its ability to bloom profusely in our hottest time of the year, is its prolonged blooming season. It can stretch through October, if we just perform two simple cultural practices.
Many people have a love-hate relationship with crape myrtles. These plants can handle any weather we throw at them, but they are messy around pools. And that can be aggravating. And while it seems a transplant or neglect can kill them, they grow too many sports/sprouts making them appear unkempt.
Still, you have to absolutely love their ability to bloom beyond just three months in the summer if you’ll do just two itty bitty things.
First, prune off all the blooms heads that have run their course. Then feed them.
But time is of the essence - you can’t wait until September to decide to prolong their blooms. And while the protocol for prolonging the blooms sounds pretty simple, there is a super big caveat.
To get the best possible chance of new flowers, you need to trim the stems that are the more greenish. The more woody or brown the stem is just under the bloom cluster, the less likely it will set a new bloom head. So, think selective pruning.
Okay, I lied. There is a second caveat.
You're supposed to prune back to where new side-shoots emerge from a branch. If you don't see any, prune very long branches back about one-fourth or one-third. Shorter branches can be prunes less than that. You’ll then get branching, new buds forming, and a new flush of flowers should follow.
Then you feed them! But here's one last helpful hint: Use “super bloom” type fertilizers. If you can’t find a food specifically for crape myrtles, water-soluble bloom-boosters such as Carl Pool's BR-61, Super Bloom, or even Miracle Gro are good. Anything with a super-high middle number. Carl Pool’s BR-61, for example, is a 9-58-8. But many independent nurseries, garden centers, feed stores and Ace Hardware locations in our region carry very specifically designed crape myrtle foods, most of which have high middle numbers.