Hi, alaMel. Yes, a lot of people in Zones 4-5 have complained about ES. I still remember looking at the website when it first came out and it said 'hardy to zone 4'. Then they changed the comment to suggest winter protection in zones 5 and colder.

Now, I should point out that hydrangeas sometimes take several years to develop a good root system and grow strong and fast. In the meantime, you see no growth or little growth above ground. So waiting can be normal and is ok. In your zone, the arrival of warmer temperatures will kick off the growth spurt but your growing zone is short so the growth spurt will not last long; all of which can make ES seem slow.

Do not feel alone; I am in the same boat too. I have a Glowing Embers that will be about two years old as of mid July but has stayed about 1.5 feet tall so far. Short and slow compared how other hydrangeas here have done. I like the blooms so I kept her.

To help it develop a good root system, make sure that the soil is acidic, moist, well draining and well mulched (3-4") as often as possible. Add about 1/2 to 1 cup of composted manure in June to fertilize the soil. You can sprinkle coffee grounds too, thru July.

ES's size at maturity (in 10 years) is around 3-5' tall by 3-5' wide. So it still has time to reach those dimensions. Of course, dieback and a short growing season will make it reach dimensions around 3-4'. In the southern states, you have a better chance of reaching or exceeding the 5 feet height and width.

Other things that you could do: adding winter protection will help minimize dieback; stopping fertilizers around July will make sure that new growth is not zapped by early frosts; keeping the soil moist (until the ground freezes) will ensure continued growth; and of course, you could always replace ES with a hardier one like some of the arborescens and paniculatas.

For more information, see the Endless Summer Website in the link below.

Luis

Here is a link that might be useful: ES Website

Give it some time. Once they establish they are impressive in zone 4. Most of the growth in zone 4 will come from the base.

Mine followed the old adage, first year it sleeps, second year it creeps, third year it leaps.

Mine took six years to leap. Possibly because I've provided no winter protection, my ES provided no blooms. Well, that's not completely true; we saw one or two blooms every summer. I think it would have done better last year, and the year before as well, had we not experienced a killing frost (actually a freeze) in early June. The plant was looking good until that point.

But this year it has exceeded all my dreams. For some unknown reason, it didn't suffer nearly as much winter dieback as usual, and it leafed out beautifully. Now it's covered with buds, and I'm excited!

Last year it produced only one bloom, but it was lovely.

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