This is quite typical for many varieties of crapemyrtle, and there isn't much you can do about it except to consider trimming off spent flower heads (those going to seed) to reduce the weight on the branch end. This phenomenon happens to young plants too, where at the nursery they're being grown, since they have more slender stems at that age, they can bend considerably after heavy irrigation or rain. Usually they become upright again after blooming. Avoid heavy, regular pruning of the tree as this results in a worsening of this issue, since regrowth from drastic cut-backs is weaker than the original branch structure had been and will be more prone to breakage. The plant pictured does not appear to have been pruned that way in the past, but we wanted to mention it just in case it was being considered going forward, since the practice of "topping" crapemyrtles, even though not at all healthy for the tree, is unfortunately still widespread.

Miri

Thank you for this super helpful information. We inherited this tree from the previous homeowners and are new to crape myrtles. I appreciate knowing not to top it. What kind of pruning, and when, is appropriate? The tree is situated right next to the house and we have trimmed a few of the branches that started scraping the window, but nothing drastic. The other side of the tree (where it's bent in the photos) hangs right over a set of steps, so we need to keep proper head clearance there. Right now we have to almost double over going down the steps in order not to hit the branches.

Crapemyrtle should not need any regular pruning outside of that which is typical for maintaining the health of any tree: removing crossing branches (so the bark doesn't abrade away where they rub up against each other), pruning off storm breakage or dead wood, and selectively thinning-out any areas with overly-crowded branches (where they connect to the trunk very close to each other). Branches in the way of a walkway can definitely be trimmed back as needed for safety/convenience, and now is an okay time to do so.

Our Pruning Trees web page provides some general guidance, though it's geared more towards mature trees needing more substantial pruning than this one. The "proper pruning cuts" section will be the most relevant, since it applies to any type of pruning so the cut is made in the right location.

Miri

Great, thank you so much. Appreciate the link to the pruning page, too.

You're welcome.