I do not live close to you but adding snow (like you did) is a good way to shield plants from frigid temperatures!

One of the better features of Endless Summer Original is its increased hardiness. Unlike most other bigleaf hydrangeas, this is fully root hardy to zone 4 (-30F) so you should have no concerns about winter hardiness in your zone. In fact, this selection (and all the other cultivars in the Endless Summer series) was developed by Bailey Nursery, located in St. Paul MN, specifically for cold climate gardeners.

If you check out their website, their instructions for winterization are to stop fertilizing by August 15 and mulch with 4" of mulch (leaves, straw, bark, etc) when the plant is fully dormant or around November 30. There is no need to cut back top growth or wrap with burlap (although you can if desired), as this hydrangea blooms on both old and new growth. It can die back to the ground each winter and still be expected to bloom the next summer on growth produced that same season. Any snow cover is just an additional form of insulation and may protect old growth -- while the air may be at subzero temperatures, the soil surface under a thick snow cover will often hover right around freezing. Remove any obviously dead wood in spring.

I've not heard any stories about first year fragility with ES necessarily although there have been numerous reports about the plant not blooming as profusely as advertised. A lot of how well a plant survives its first winter in the ground has to do with when it was planted and how well it was able to establish before cold weather sets in. As long as it was early enough in the season to develop a proper root system (like before October 1 in your zone) and it received adequate care, there should not be any problem overwintering.

Lizzie, I'm in Zone 5B and my ES overwintered fine the first year but growth during the second summer was slow. I didn't do anything special to them, i.e.,cover with a barrel/burlap, etc. Now, 3-4 years later, they are thriving.

I mulched mine the first winter, but have done nothing to protect them the last 4 winters. I've learned not to prune them back to early, even if the stems look dead, they have fooled me. Some winters we've had good snow cover, some not.

I live right on the edge of 5B/6A and cover my macrophylla hydrangeas with about 16 inches of leaves around Thanksgiving time and uncover the last week in March. They all perform magnificently, especially Endless Summer which probably doesn't even require this level of treatment given its hardiness. In fact, on a Nikko Blue hydrangea 104 flowers were in bloom all at once last June (plant only four years old). If this winter ended up being bad for your hydrangeas, consider growing in a large pot (like 14 gallons or larger) and then overwintering in an uninsulated garage or shed. This is what I do for the varieties that are not so winter-hardy.

I have an endless summer planted between 2 large (10 feet tall) Holly trees. I never do anything special to it over the winter. It looks dead but I just noticed some green leaves sprouting today. It is 2 or 3 years old, some sun in the early morning. It bloomed last summer, it is a beautiful blue. I was thinking about cutting it back above the leaves sprouting now but I don't know what it do??
I live in Phila., we had a lot of snow this winter.........

Lizzie, I know this thread is a few months old, but I'm pretty close to the same zone as you though a bit closer to the ocean. I've never done anything to winter protect my ES's, and they've always come through like champs. I cannot say the same for my Nikkos. Of course, both ES's are right next to the house, so that surely helps.

This year I finally got around to winter protecting my Nikkos albiet I was likely a little late. We'll see if I had any luck.

Thanks! Sorry I didn't follow up on this post sooner. It's good to hear how hardy this plant is - I know the whole allure is that they can survive cold areas, but I've still read about them not making it through the first winter.

Today, April 6, I still have tons of snow in my yard, but most of the snow that was on this plant is now melted. So, I've got the plant covered in dead leaves, with just one large piece of ice on top of the leaves. Because I didn't use a barrel or a wooden frame to protect the plant, and instead just threw the leaves on top and left it open to snow, it's gotten really crushed down. (We got a lot of snow all at once this winter.) I'm not sure when it will be safe to uncover it - is there any reason to wait until the last frost (which here is not til early June!?) Or, since the plant should be dormant and has been in freezing temps all winter, will it be okay for it to now be exposed to frost? I'm dying to know what shape it's in now. I suppose if some people never do anything to protect the plant, and they survive, uncovering it now should be fine.

Lizzie, I'll be waiting for the answer to your last question, because I'm in the same boat! I'm so ready to uncover them, but I don't want to jump the gun. We still have 3 weeks to go before last frost.
Karen

I planted my Endless Summer in a container. First year it was loaded with huge green leaves and big pink flowers (still working on the right amount of aluminum phosphate to use to turn them blue. Wintered it over in the garage where it goes down to about 20-30 degrees. Kept it watered once a month and low and behold there are about 7 or 8 new tall growths of wood growing. It looks very healthy. I'm worried about hardening it out like how many hours of exposure a day,The CO sun can really fry tender shoots. What I love is that I broke off a shoot and rooted in water. After 5 months it is gorgeous with green/red leaves and a bright pink new flower...growing in roots floating in water in the vase! Has anyone tried propagating?

Hi. I planted several endless summer last year. I did not do anything special for winterizing, no trimming, no mulching or covering. I live ~ 40 miles north of Chicao. We, as usual, had a very long and harsh winter. And there were times the plants were not covered in snow for extended time period with very cold temperature.

They all survided. We started to see some spring weather and temperature, so I went out today and examine the hydrageas. New life started to grow out of all the endless summer plants.

A couple of my neighnors also have endless summer for several years. They never do anything for winterizing. And every year the hydrageas came back nicely.

They seem to be very hardy for our Zone 4/5a, and long cold winter climate.

All the best,
Vivian

Hello - I read this thread at the start of this Spring-clean up season & promised to return as soon as I have cleaned around the back where my 2 6y/o ES are ~ but alas that was 2weeks ago ~ 'tis taking this long to get all the clean-up so far, whew ~TG for these 2 days of colder/intermittent-rain ~ rest much needed & ease the muscles & joints that lay dormant for months!!!

I was new to Hydrangeas in general, when I planted my 2 ESs so for fear of losing them ~ they were coddled well for the first Winter & gradually relaxed as I gained knowledge & confidence over the next few. These past 2 I left them to fend for themselves w/ just recommended amount of dry-leaves mulch. Last year they both grew well but bloom-production were less that previous years only due to the July-Aug steamy heat~wave ~ w/c to my experience is as bad as a killing Winter!!!

This past week Both promptly showed eagerness to stretch out to Ma Natures call, heralding Spring!!! So far so good!!!

I took the covers off my nikkos last week (late spring here). 2 were already starting to leaf out. One looks like crap. The ES's are not leafing out yet which is odd. They usually have a little green under the snow. I'm just waiting for the ground to thaw because I have to dig deep to transplant the massive ES. I'm glad it's still asleep. However, as soon as I wrote that, I realized that I will see green tomorrow. lol

We've had such extreme weather since last April. I wouldn't be at all surprised if the Nikkos blooms this year and the ES's don't. Ha!

The past 2 nights have been below 32 degrees, so the Nikkos get blankets (but not the one that looks like crap. I've already written his blooms off this year).

HI mehearty - similarly i waited 'til I was comfy enought with the day after day of unseasonably sunny & even near 90ð (couple of days) before undressing my seriously winter-covered H Divas ~ sure enough the cold returned TG not sub-freezing enough to be running for cover-ups!!! Mid Apr was when upper 70ðs days ended & here we're enjoying much awaited rain but sustained overcast mid-30ð-50ð thru this Holy week! Most all have leaf'd out & 2 have fat-buds ready to stretch open. Mighty sun will show up again by Easter Sunday!!!

Don't give up too soon on ES - her new woods will please you for sure!!! Our Mid-West steamy heat kill bloom efforts more than Winter's cold!!!

Heeeee! Look what Nikko's got!

The Nikkos were protected and the ESs weren't. The ESs have buds too.