I don't think you need to. They are paniculatas and quite hardy and resilient. There are certainly zone 5 posters here who can speak from personal experience.

You don't. Perfectly hardy into Zone 4 if not Zone 3.

If you feel like you need to help them, maintain 3-4" of mulch up to the drip line. Not really necessary in MA but it helps protect the roots. Snow will also help protect them from the cold and the drying winds, although way too much snow may weigh a lot and snap some stems; would be rare but you can keep an eye on that and take appropriate action if/when you deem it necessary.

I don't do anything for mine and I'm right on the border between zone 4 and 5. Never had any dieback, broken branches or any other winter issues on my H. paniculatas, not even vole damage.

Because deer eat my Limelight I have been putting chicken wire fencing around mine with deer netting over the top. This is still a short plant.

Re: short plants. Do you put very tall chicken wire so they can't get to the short stems that are standing up? If so, how tall? I do not have deer here but I have never seen anyone mention that. I tend to go for 6' or higher as a result when I do buy chicken wire.

Yes, I do go all the way to the top with the chicken wire. Just put the deer netting over the top. No problem when they are protected. This spring after I removed the wire they ate the tops of the plants resulting in late and small blossoms. Thought that one side wasn't going to have any blooms at all as the side they couldn't reach started blooming sooner. One year they ate the stems very close to the ground. My plant is only 4 ft tall and about three feet wide. Deer and rabbits are a pain.

Rabbits are the problem here but I have not seen them pestering for the last few years. Maybe my dogs and backyard fence are keeping them away somehow (the front of the house was the one that provided the tasty morsels for the rabbits since those bushes are not 'protected').

You could try pinching to get more internal growth and maybe higher nitrogen levels in the fertilizer (in Spring, not now) but I would let it grow on its own schedule. If it starts getting much bigger on top, winds may suddenly become a problem and may cause you to stake the trunk again.

Perhaps you should also evaluate it in Spring (after leaf out) and not at a time of the year when L and LL like to drop leaves and have 'naked feet' as it may look "smaller".

Hi - I live next to Cambridge MA (close to you, but 6b) and have never done anything with my 2 Limelight hydrangeas (no winter protection, no fertilizer, nothing). They are very happy - tons of blooms. (Remember that Limelight blooms on buds that form after the winter is over - so, they aren't like non-reblooming mopheads, which form the flower buds before winter and, thus, we here in snow zone run the risk of them being damaged and not having flowers the next spring/summer.)

do you cut back the dead leaves and and stems?

Monica, You can do some pruning for shape or to reduce next year's size if you want, but the dead leaves will drop off. Since this isn't a perennial, it's a woody shrub, stems aren't generally cut back, just for shaping or size modification. I haven't ever cut my Hydrangea paniculatas since I like both the size and shape they have.

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.

Limelight is deciduous so it loses it's leaves in the fall.

I think it is considered deer and rabbit resistant because it blooms on new wood so if they eat them in fall, winter or early spring they will still bloom. If they get routinely munched in the summer they will not bloom as well.

As Pennlake said, Limelight (and all other H. paniculata) leaves are deciduous, starting right around this time of year in New England, but the flowers will remain until trimmed off. I like to leave the flowers on my H. paniculatas since I want the plants to look as dense as possible in winter, and I think the tan dried blossoms add interest. I prune off the previous year's blossoms in early spring. Here's H. paniculata Quickfire in November in my yard.

Whew, that's a relief.

Mine had lost its lower leaves earlier in the year, about a foot to a foot and a half off the ground. I'm not sure if it's disease or rabbits, but since it's in the back of the garden, I don't mind planting stuff in front to hide it. Besides, I could always use an excuse for another rose. As long as the upper branches come back. And right now, it is kind of nice having the pale brownish flower clusters in the center, going well with the gracillimus Maiden Grass at the ends of the garden.

Rose, the lower leaves may have dropped off earlier this year due to transplant shock since they are new plantings. If so, it will not be something that happens next year. Mine don't seem to have issues with foliar diseases, and thus far nothing has eaten them, including the voles which eat virtually everything else with the exception of daffodils.

My limelight seems to have grown out more than up. Should I put steaks around it to make it grow more upright?

Is it "growing out more than up" because its blooms are flopping due to the weight of the large blooms?