Have you ever pruned your Little Limes? Panicle hydrangeas like Little Lime, Limelight, Quick Fire, Pinky Winky, etc. bloom on new wood, which means if you prune them in late winter/early spring, there is no risk of pruning off this summer's flower display. I work at a landscape nursery in SE Michigan and I usually advise clients to leave the dried flower heads on for winter interest, then prune the entire shrub by about a third in early spring. Add a little slow release, organic fertilizer, refresh the mulch if needed and that's it. At the nursery we have mature examples of several different types of panicle hydrangeas growing in the landscape. They are pruned annually, put on a spectacular show each summer, and I've never noticed any flopping.

Try it this spring and good luck!