Hello. Hoping someone here can give me some overdue advice that I need!

I purchased two strawberry vanilla hydrangeas in April from a local nursery that were overwintered there.They were still dormant when I purchased them.

One came out of dormancy like normal and is covered in leaves and has 4-5 blooms on it now! The other one sat bare so in June, I mentioned it to the couple that owns the nursery to see if they had any advice for me and the husband insisted I just take a new one. Since these are in the very front of our property, I planted the new and transplanted the dormant one to a less viewed location in my big garden.

It seemed to like the new location better and put off 5-6 leaves. And that's it. Since then it's done nothing. The bare canes are all alive (I do the scratch test every few weeks to be sure), but it's just not producing any more leaves. I water it regularly and the soil is mulched. All my other hydrangeas are doing great so I'm wondering what I can do to give this one a little TLC. It's a little late in the summer perhaps but you all have such wonderful advice I'd like to see if there is anything I can do.

Other stuff you may want to know:
I gave it a little 20-20-20 fertilizer in July (we had a very cool July here in Iowa.. most days around 75 degrees) and that didn't seem to do anything. However the leaves it's putting off are bright green and healthy. It gets full sun with dappled sun in the afternoon. I'm really not sure on the quality of our soil but I have 4 hydrangeas, and 12 roses growing quite well and a perennial garden. Nothing seems to struggle except this little guy. Let me know if there's anything else that could help.

Thank you in advance for advice. Everyone here is always so helpful!