If you're talking a serratta (mountain), I would say at least 7 feet.

The blue one (mophead) will get big over time...if you don't get winter ground dieback. Definately plan accordingly...but at 3 feet, def too close

One of them is definitely the Mountain Hydrangea: Tuff Stuff™ Reblooming Mountain Hydrangea Hydrangea serrata.

The other one didn't have a tag. Here is a photo of it. Does it look like a mophead?

a1an and gardengal48: thanks for your advice! I'll move them to another location then.

Would it still be ok to move them now or do I have to wait until early spring? I have some spots that get strong afternoon sun. Will that be OK for them in my zone 6b (central NJ)?

I am planning to get a ph tester. I have pine trees in my backyard and lots of pine needles.

Don’t move anything now. Summer will crush them. Fall is best time for transplanting so wait till about September 15. Just look at 10 day forecast.

Both would prefer a location with morning sun but shade in the hot afternoon. And if you need to, test for soil pH. Pine trees or an accumulation of pine needles is not an indication that you have an acidic soil. Although most places in NJ do.

Agree with waiting to transplant.....now is not a good time.

WAG, your pH is about 5.2. If you are planning on keeping track of pH, get indicator liquid or pool strips. Unless you are willing to pay a lot of money, and keep them calibrated, the pH meters are useless.

I, personally, would be a much happier camper if pine needles really made soil more acidic. My rugosas would cheer.

Move the roses to the full sun spot.

NHBabs, I don't have a full sun spot in my yard :-( My side yard is the most sunny spot, morning sun from 8:30, after 3pm or so, it will be partial sun (filed through the pine trees on the west side of the yard). My back yard will get sun from 11am or so, and then afternoon sun.

My front yard will get sun from 10am to about 2pm, then no sun at all. I have two hydrangeas (from Home Depot) grown here since last year. None of them has any buds yet. That's why I didn't plant my new hydrangeas here.

@mad_gallica, I am curious - how did you know my pH is about 5.2?

Without winter protection in your zone, bigeaf hydrangeas (H. macrophylla) are unlikely to produce many flowers. It is not the lack of a sunnier aspect that is preventing flowering but rather winter and spring cold. Mountain hydrangeas are slightly more cold tolerant but I'd still go to the trouble to winter protect if you want reliable flowering.

Your front yard actually gets perfect sunlight conditions for these. But your cold winter climate will prevent more flowering.

btw, that does look like a mophead in the added photo. But I doubt you will see any pink from that one, lime or no lime.......it looks like a white flowered variety :-)

Interesting - you ask if it’s ok to move the 2 hydrangeas now. Strong advice against doing it “now“ proffered by 2 posters. Your 2 hydrangeas were planted “2 days ago” (you write, yesterday).

Wi-Fi, I don't know that your pH is 5.2. It is a WAG - wild ass guess. However, that was what my pH in suburban Philly was, and there are general pH maps that have that entire area looking the same. Basically, it is going to take an awful lot of lime before you even start to get into problems from having too high a pH.

mad_gallica: a WAG is good enough for me :-)

gardengal48: I love white hydrangeas too! I think I'll move both to the front yard then. They'll get more sunlight in the winter when the leaves are all gone.

rifis: I did just plant them on Sunday. I think I'll move them tomorrow. Yesterday when I went home, the mountain hydrangea looked thirsty with all the leaves drooping even though it rained the day before. We are only in the upper 70s to mid 80s now.

It just need to settle in on roots and or depending on what environment it was taken out of, a little bit of hardening. Temps aside, the sun intensity is almost as intense as it is in the summer.

My locally-owned nursery will do one free pH test w every visit. You cd see if any nursery convenient to you offers this service. . .

WiFi, anything over 6 hours qualifies as full sun. As others have said, hydrangeas are happiest with morning sun, though many of mine get sun until early afternoon.

I have Tuff Stuff which blooms every year, most years quite fully, though I had one season that wasn’t as good. Mine dies back to the ground every year and blooms by midsummer on new wood. Most macrophylla/big leaf hydrangeas bloom little if at all most years. I do typically have good snow cover.

Most of NJ has acid soil as do I. Why are you adding lime? If the plants don’t look unhappy, they don’t need lime. The only garden area I have that gets lime or wood ashes to raise pH is the veggie garden, and my soils have native blueberries and rhodora/Rhododendron canadense, both of which like acid soils. My ornamental seem to do fine as long as I am not planting things that strongly prefer neutral to alkaline soils.

I took out my Nikko Blue hydrangea this year. It had been in it's present location on the east side of the house for about 15 years after having been moved from another location the previous 10 years. It was the type that bloomed on old wood and I only saw a flower maybe once in the past four years. It's best to get the kind that bloom on new wood if you have cold winters. My hydrangeas get morning sun until just after noonish but they wilt in the heat despite whether they had just received water the day before. They always recover quickly once the direct sun is gone. Mine were huge even with total neglect.

NHBabs, I didn't know 6 hours qualifies as full sun! I did just move my Tuff Stuff to a place where it would get sun until 2pm. I haven't touched my big leaf yet. I have two big leaves that haven't got any blooms yet (second year in my yard). I thought it was due to lack of sun. Now I know why.

I bought lime because I saw the big pink hydrangea bloom on the cover. I love pink hydrangeas. I guess I'll hold off feeding them lime then, since my soil is acidic anyway. I saw this beautiful pink hydrangea at the garden center. If it will turn blue, could I keep it in a container and just bring it indoor for winter? I googled winter protection, it sounds like a lot of work!