Should I seal the wounds where limbs were removed on a crape myrtle?

Question

I have a crape myrtle that I attempted to transplant last spring. Unfortunately, it didn't do so well (I damaged more of the roots than I intended), and while it did leaf out last year, after a long cold winter I thought for sure it was dead.

But, to my surprise, around June of this year, it started to leaf out just a little, and we even got some flowers! I've trimmed off all the dead wood (which, unfortunately, was most of the plant), and I'm hoping and praying for the best.

It occurred to me that every pruning wound, or place that I cut off deadwood, is a potential avenue for bugs or pathogens to invade the plant, which would be bad news in its already weakened state. Is it a good idea to seal off the ends somehow? If so, with what? I have a wax sealant intended for use on hardwood decking. Is that, or another product, a good idea?

Answer 1

According to Wayne K. Clatterbuck in the article Tree Wounds on the Texas A&M AgriLife Extension Tree Care Kit:

Research indicates that wound dressings (materials such as tar or paint) do not prevent decay and may even interfere with wound closure. Wound dressings can have the following detrimental effects:

• Prevent drying and encourage fungal growth
• Interfere with formation of wound wood or callus tissue
• Inhibit compartmentalization
• Possibly serve as a food source for pathogens

So don't treat the wounds. The only thing that the plant needs is a good, clean cut to heal over. If you already cut out the dead, you did the right thing, and it would be best to leave it.

Answer 2

Whilst it was once considered essential to paint wounds on trees with a protective/preventive treatment (Arbrex, for instance), this practice has long since fallen out of favour - turns out it often caused more trouble than leaving the sites untreated.

It sounds like you've only removed dead parts anyway, so there's much less risk of any infection gaining access.