Interesting question. In my experience they seem to enjoy all with equal fervor, though I will say they have yet to nibble on my lone paniculata. I don't have any arborescens, so can't speak about them. They have eaten on oakleafs, macros and serratas in my garden. I was weedeating around my Clethra barbinervis yesterday and could see where they had been eating it too. My first time to witness deer browsing on any Clethras.

Strange.... Is this happenning to all the stems, most of them or just a few? If it is a few, do you think it could be because the plants are young and the stems have not hardened enough to hold the weight of the blooms? Could they be in a windy location that makes the young stems move around too much? Any chance they were mistreated at the nursery (did some of the plants for sale looked ragged, in bad shape)? If not pruned now and then, other types of hydrangea bushes can become very 'leggy', growing upwards until the weight of the stems is greater than the stem's strength, at which point the stems will sag down to the ground and possibly break. But gosh, your plants are so young that I would expect, at worst, that the stem bends (not break) a little. Deer will nibble but they mostly like to eat leaves, not the base of the stems unless they smelled something there. I am sure that they could even pull hard and break some stems. However, you probably would have mentioned that leaves looked eaten. My only damage to the stems (not Limelight, other types of hydrangeas) has been courtesy of my playful pooches. Regardless, go ahead and put something to support the stems. Then keep an eye to see if you can determine how this is happenning. Luis PS - if you could post pictures of the shrub and the damage, that might give someone else additional ideas.

The critters "broke" into our nursery at the arboretum one night and munched on all the paniculata and arborescens. Didn't touch the year old quercifolia seedlings. On the other hand, they have not bothered the arborescens planted out in the collections and the only paniculata we have in the collections are tree size and the foliage is too high for them to reach.

Eeek. I didn't realize deer would attach limelight hydrangeas. But our limelights have lost all their leaves, with just the flowers left. Would that be deer, or something else? I didn't think they'd just lose their leaves in the fall. The designer who did our plan largely specified rabbit and deer resistant varieties, so I was surprised to learn about these. We never had a significant deer problem with our rhododendrons, and the rabbits haven't touched the mountain hydrangeas we have up front. But if the deer (and rabbits) are gong to destroy the limelights, I'm going to have to search for an alternative shrub.