yes.. its really more a question of how ugly they will get in summer after the onslaught of heat ...

just always remember.. that most hings are shade TOLERANT ... and the issue is more along the lines of whether then can process.. or you can provide.. enough water ... for them to look good.. all year long ..

e.g. hosta are shade tolerant .. but the sweat ... give off water ... so by july.. august.. they can start burning .. or browning .. and though they can get real ugly ... they actually grow with more vigor in more sun ... so that by next year.. they are actually larger plants .... i used to tell peeps to grow small plants in more sun for a year or two.. and then move them to more shade ...

of course.. the further south you go .. the less sun things can take.. but that is adding more variables.. like light intensity ... etc ...

ken

I wouldn't do it; they'll look nasty for too long. You could try Hydrangea quercifolia - it can take full sun here, and requires less water. They have the advantage of giving you good fall color, as well.

Tolerate? Sure. Thrive under those conditions? Maybe not :-) And much will depend on the variety as well. I would never intentionally site Hydrangea macrophylla in full sun regardless of location. Even in my very mild summer climate and with reduced sun intensity due to my very northerly location, these will wilt or scorch with this exposure and the flowers will bleach out and decline rapidly. OTOH, Hydrangea paniculata or quercifolia are quite happy in full sun here. Most evergreen azaleas are also quite happy in almost full day sun and the deciduous ones perform best in a lot more sun than shade.

But this is the PNW.....can't say the same for anywhere else.

As a general rule, provided you can provide ample moisture, most plants would prefer more sun than less. A lot of our shade tolerant plants (hostas, heuchera, hellebore, etc) are really just that..shade tolerant and often have mostly sunny placement in nature.

Not to say (in particular for fine textured plants or those with very broad leaves (like the hydrangeas referenced) that there aren't plants that really dont like hot midday sun.

Azaleas as a general rule like 1/2 day sun, with some midday shade.

Take a look around your neighborhood. Do people grow hydrangea macrophylla under full sun successfully? How well do they handle high temperatures?

The Original Endless Summer hydrangeas are popular in my area. Many people grow them in full, direct sun (front yard, next to the side walk). Those that get afternoon sun wilt a little but recover by sun down. I find Bloomstrucks to be more sun tolerant than the original. I planted a few in full, direct sun (8+ hours) because that's the space I had to work with. A few leaves scorched when the temperature gets above 90, but other than that they are growing very nicely. Good luck!

Hydrangea macrophylla is a woodland understory plant by nature. When growing in the wild, it is always found in a partially shaded situation, usually sheltered or shielded from direct sun by the canopy of a larger growing tree. There is nothing in the cultivated forms that would alter this natural preference.

If full sun is your only siting option, then go ahead and attempt....but be prepared for some less than desirable results. I would still never recommend siting in full sun anywhere if other, more preferable locations were available.

I would go to the New Jersey Botanical Gardens and see the plants in there...and even see their Azalea Garden!

How do they get adequate water under a tree when they'll just suck up all the moisture? My dad took some pics of hydrangeas in the hydrangea temple in Japan and the hydrangeas were right next to the trunk of a cryptomeria. I wonder how on earth they get any moisture. Does that mean I can have them under the canopy of large maples and oaks?

But ok, so I guess azaleas fine but not hydrangeas.

In my area, wild hydrangea grows on bluffside and streamside where they typically aren't in direct competition from tree roots, or if so, the constant moisture makes it irrelevant.

My Little Lime Hydrangea get full morning sun until early afternoon, little water and look fabulous. My neighbor has Endless Summer on the north side of the house and they look healthy but I don't think they bloom much.

It is important to understand that different hydrangea species will prefer different growing conditions. Hydrangea paniculata and quercifolia tend to be more sun and drought tolerant than H. macrophylla. And H. macrophylla's ability to flower well is strongly influenced by winter cold or late spring freezes and any pruning.....even the so-called rebloomers (new wood).

Ok well the only partially shaded location I have would be right at the end of the canopy of an acer rubrum. Would that be a problem, provided that I give them enough water? The hydrangea I'm planning to transplant(in fall) is about 4 feet tall and wide.

I have lime light hydrangeas that are planted in a row in full sun, I’m in zone 5 in central Indiana, in the last 3 years I still don’t see any signs of burning or anything else related. They are very healthy and thriving

It probbaly depends on the type of hydrangea and azalea. Some of them do and some dont

In extremely moist and salubrious maritime climates - not exactly something we have in the US - both of these absolutely not only grow, but thrive in full sun. Not exactly something we have in the US, but I'm sure if I could teleport myself to Eureka, CA, right now, or various high elevation parts of Hawaii, I'd find some H. macrophyllas and Azaleas in "full sun". Here are some in the Azores, where H. macrophylla, at least, has become a weed: http://www.growingontheedge.net/viewtopic.php?f=2&t=10994

I'm sure I saw them in full sun on the west coast of NZ and thought nothing of it: Greymouth - Wikipedia
Standard situation for any rhododendron hybrid there, for example, is in full sun. Even fancy ones like 'Nancy Evans'. Easy to do when there's some form of rain or fog on 85% of calendar days if not more. Look at that yearly total - and no months below 6 inches! The PNW's dry summer means you'd have to at least be watering in JJA, if you expected to 'get away' with that sort of planting.

Yes I don't know why people are mentioning panicle hydrangeas, I'm only asking for hydrangea macrophyllas.

Ok David, but how about for us northeasterners? Will they take full sun there? And how about if they are sharing roots with a mature acer rubrum? Of course I will be watering it like crazy to make up for it

I'm not one to advocate willy-nilly removal of trees, but if you can replace the Acer rubrum, I'd consider doing so. They are monstrously difficult to garden under. Your posts imply you own your residence and intend to be there indefinitely ;-)

As the other posts suggests, we don't tend to see these plants in full sun in the US. That being said I can totally believe there would be some watered hydrangeas in almost full sun situations, especially along the northeastern coast like Martha's Vineyard etc. Evergreen azaleas, too, although I suppose they will be burnt in colder winters. But it's definitely not the optimal place to put them in our climate.

No I'm not the owner of the house, its my dads and I still live with him. I'm just trying to make a neat garden just for the fun of it. Well, its actually right at the end of where the maple's roots are. The hydrangea will barely touch the root of it. So not sure if that makes a difference. I think this area gets sun from 10AM to 3:30 PM which idk is too much or just about enough.

Acer rubrums are notoriously hard to garden under or near. I had mine removed and am so happy they are gone! Red maple will soak up most of the water you supply, so hydrangeas may even wilt despite good watering. Red maples 'learn' where the water is and quickly develop an extensive fibrous root system in those areas.

Hydrangea macrophylla will bloom better with 'some sun'. In deep shade they may not bloom at all. However, in deep shade they won't wilt nearly as readily.

In full sun or blazing afternoon sun the leaves will wilt or be damaged with no additional water. The best location for them is morning sun, open north exposure with some early morning or late afternoon sun, or late afternoon sun. And of course, try to minimize the root competition from trees.

Maples are tough to grow under, Their roots are shallow and really suck up moisture. You may need to water plants often to keep them healthy.

I grow the hydrangea 'Pinky Winky' in full sun. Foilage looks great all summer long even when it is super hot. Very reliable.

'Pinky Winky' is a cultivar of Hydrangea paniculata - not the macrophyllas the OP was talking about. Paniculatas tend to be far more sun and drought tolerant (and cold tolerant) than are any macs!!

Without question Hydrangea macrophylla would prefer some protection from hot afternoon sun. While they can be grown in full sun, the appearance will be different....the plants tend to be stunted in size, often with leaf burn or scorch, flower heads will be smaller and the flower color will be impacted. Sometimes bleached out or sometimes taking on very dark tones. And the flowers don't last or look 'fresh' as long as they would if the plant received some afternoon shade.

Oops. I didn’t fully read the post. Please ignore.

Just a quick data point. I have some new macro's in FullSun 6AM-6PM. On the initial summer/heatwave this year, they wilted pretty SAD. We've going through another heat wave this week and sofar, even the new plantings are Perky. I can't say if it's just larger rootsystem that has occured or JUST acclimation. All in all, it's interesting to observe said differences.

So for all you hydrangea garden gurus, would you say this acclimation is permanent or it be a seasonal thing where they may wilt in extreme sustained sun conditions in the early summer season but lessen more as the season progresses... every year ? plant's dont' have brains do they - I dont even know how this acclimation occurs in plant-o-logy

I will say this - in my trials. New plantings in full sun show new stems. No new blooms on new stems. Maybe stressed. Same planting in morning sun/after shade - new stems have developed new blooms. Less stressed I suppose ?

Gahh I hate part shade plants. Its almost impossible to find a part shade location in your yard. Everything is either full hot blasting sun or full shade or morning shade/afternoon sun. Never morning sun and afternoon shade. Nature won't give it to you so easily. And if you give all day dappled sun under a tree, they may not even bloom.. hydrangeas, azaleas. Such beautiful plants but why do they have to be so finicky?

A1an, at my workplace there are many hydrangeas in full sun. Definitely 8 hours or more of sun. They are at least 10 years old and they are very big. They still wilt every time temperatures get hot and is sunny but perk back up at night only to wilt again in the afternoon. The wilting doesn't lessen. In my experience however, the first year you plant them will definitely wilt the most but they do still wilt even after many years and at the same level. Just never the same level as wilting as they were in its first year of planting.