For one thing, you'll get smaller blooms from *near* the tops of stems on old wood. That is, smaller than terminal bud blooms and smaller than blooms that occur at the end of new canes. If you have small terminal bud blooms I would suspect some type of stunting event.

I thought old wood was the only part that bloomed....

Since there are a number of different species of hydrangeas and those different species often require very different growing and care methods, it would be very helpful if posters told us what kind of hydrangeas they are growing. We could very well be discussing complete different plants without that information!!

For mopheads, I would do a soil analysis to make sure there are no mineraql deficiens.

I also see smaller blooms like that when the plant has been pruned such that it ends with lots of branches. Then at blooming time, you get more blooms at many of these new branches but, they are smaller.

Old, established shrubs can also do this and must be rejuvenated by cutting 1/3 of the stems each year for 3 years in a row.

On lots of breeds you'll get a few new wood blooms every now and then. I was just citing that as an example that blooms from the very ends of thick canes always produce the largest blooms, regardless or whether the cane is green (new) or brown (old).

I will post pictures this weekend... thank you all for you insight!

I am having the exact same issue this year. I am going to move mine next spring to see if location change will help. They are currently on the north side of the house. I’m in zone 7. I don’t prune them.

Same here! Endless Summers. I’m also in zone 7. Should I cut them back after they bloom so the blooms are big next year?

I had winter damage this year. I am guessing that my/your flower buds were partially injured (as opposed to getting killed) as there were few flowers that bloomed, the ones that did open were small and the affected plants were mopheads, lacecaps and serratas only (which tend to be damaged more often in winter)... Oakleaf flower buds were not affected.

I will just say that there is no relationship between pruning and flower size. So pruning after blooming - whenever that might be...in my climate they bloom until frost - is not going to help. And could very well eliminate or reduce flowering for next season if left too late.

I am in zone 7 having the same issue, I pruned almost down to ground two years ago , would that be responsible for smaller size blooms , anything I can do now ?

I have both mop heads and smooth

Wow, if you pruned them all the way down, yes, I can see that happening. I was at a plant nursery just minutes ago. They had a smooth hydrangea in two different sized pots, a one gallon pot and a much, much larger pot (guessing 5 gallons pot). You could tell there was a bloom size difference and a shrub height/width difference.

They have grown back to 4 greet height but blooms are small

much smaller blooms this year did not cut back last year

Once again, unless you can tell us what kind of hydrangea you are growing or supply photos, there is not much we can do to help.

It also helps to let us know where you are located, how the plant is sited and if and when and how it gets fertilized. Otherwise, we are only guessing.