1. In cold zones, they will die to the ground (if not protected) and in Spring, new stems will develop to replace the dead stems. You will therefore not get blooms from the old wood but, if the shrub is a rebloomer like yours, it should bloom from new wood. This is usually around July-ish. Note: you can winter protect the shrub if you want to get blooms from old wood. Maintain 3-4" of organic mulch to protect the roots from heat, cold and lengthen the times between waterings (1 gallon per plant for new shrubs).

2. Depends on what you are amending for. If your soil is alkaline, you will have to amend the soil with some regularity in order to prevent the leaves from developing iron chlorosis. This is when the leaves turn light green or yellowish but the leaf veins remain dark green.

Hydrangeas do not need extra fertilizer like roses do so adding fertilizer once a year in Spring should be enough. The plants probably come with those round fertilizer pellets so do not feed them until Spring 2015. A 1/2 cup or 1 cup of organic compost or cottonseed meal should be enough. You can also add weak fertilizers like coffee grounds, liquid seaweed or liquid fish but stop fertilizing by July so the fertilizers will not make the plant stay in growth mode when it needs to go dormant in the Fall.

If you need to amend because your soil is sandy, feel free to add plenty of organic compost.

3. No, Rose of Sharon is fine but there could be competition for resources (water, fertilizer, etc) if there is another plant with shallow roots nearby though.

Other things to avoid or keep and eye on: dense shade should be avoided as really dense shade might reduce the number of blooms; planting near the house could force you to amend the soil more often since cement leeches in new and somewhat new houses and makes the soil alkaline; plants/trees that contain juglone should be avoided; example: black walnut; you improve airflow and reduce the chances of fungal infections on hydrangea leaves if you separate all plants and not grow them close together (but you can grow them together in cases where you are doing a hedge).

Enjoy your new shrubs!
Luis

This post was edited by luis_pr on Thu, Aug 7, 14 at 1:51

Thank you Luis, this is much more info that will be helpful to keeping this plant alive. This is embarrassing but I have no clue if my soil is alkaline or acidic. I should really invest in buying one of those soil ph testers. I live in NE Indiana and my soil is clay.

I had another question if it isn't to much of a hassle to answer...my neighbor has a white Hydrangea bush and it's about 6' tall and 5' round. Their Hydrangea has never died to the ground since it was planted a few years back. Do different Hydrangeas die to the ground and other remains with hardwood? What's a variety that doesn't die to the ground?

Thanks again for the detailed answers.

Yes, there are some hydrangeas that are hardy to Zone 5 and do not die to the ground. Hydrangea paniculata ia especially hardy, produces flower buds in Spring, blooms in June-August. It produces panicle blooms that start white and then turn colors as the growing season progresses. Other possibilities that also produce white blooms: oakleaf hydrangeas (leaves are oak leaf shaped; blooms are panicle shaped) and arborescens hydrangeas like Annabelle (blooms start green, turn white and look like mophead roundish blooms).

In a pinch, you can also contact nearby plant nurseries or even neighbors to determine if the soil is alkaline or acidic. Soil pH kits are available but as the season goes on, they do not get restocked and by now, I do not find them over here.

This post was edited by luis_pr on Thu, Aug 7, 14 at 2:26

If your rose of Sharon drops seed there will be seedlings coming up within a 6' radius that will need to be pulled yearly. Some double-flowering specimens don't drop seed, though. I haven't noticed any root issues though. I have a David Ramsey 3' from a 10' tall rose of Sharon tree and it's 5' tall (taller than advertised).

Revolution isn't supposed to exceed 30" though, so you can throw leaves or straw over it in December to protect the stems through winter. If any survive they could produce flowers next season. This could be important, as there have already been people that have whined about Revolution not blooming after being killed to the ground, despite ads claiming that it blooms on new wood. So far nothing from Plants Nouveau has proven to me that any of their claims haven't been a sham thus far (aside from the fact that the spent blooms - if you get any - do make good cut flowers).

Cal I live in a colder zone and both my hydrangeas (Macrophylla) are planted against the porch.
My soil is sandy, they grow under a giant maple, in dappled shade.

FWIW:

My hydrangea macrophylla have never died to the ground.
Though they are covered more or less by snow in winter.

They hate afternoon sun and heat waves, their leaves systematically droop.

If your soil is alkaline, or even neutral you'll see the color change from blue to purple/ mauve and to pink in the coming years. The change is gradual. And you might have a variety of different colours from bluish to pinkish tinge in between. If not they remain blue.

Both hydrangea paniculata & hydrangea arborescens are hardy to zone 3.

Check the site linked below, it helped me a lot when I was beginning just like you :-)

Here is a link that might be useful: All About Hydrangea

Is the rose of Sharon in full sun? What about the hydrangea? Seems like it would be preferable to have it in morning sun - dappled shade for the rest of the day.

Hmm, not sure if I would like the blooms to look upside down every year or not... Does look nice when I stand on my head though. JK!

Thanks True, I have bookmarked that site.

lol hcmc, I just took a quick downward shot of the flowers, not the best photographer. :)

The rose of Sharon is in full sun but this Hydrangea will be in morning sun till about 1PM.

Springwood, having trouble parsing your meaning here:

"So far nothing from Plants Nouveau has proven to me that any of their claims haven't been a sham thus far (aside from the fact that the spent blooms - if you get any - do make good cut flowers)."

Brain on blooey today (sorry). Are you saying PN's claims are false (exception noted) in regards to Revolution? Sounds that way, especially added to your additional statement about Winter protection:

"This could be important, as there have already been people that have whined about Revolution not blooming after being killed to the ground, despite ads claiming that it blooms on new wood."

Revolution is the only one of the "Everlasting" series claimed to bloom on both old (if it survives) & new wood.

Here is a link that might be useful: Revolution

Well I'm not saying PN's claims definitively aren't true, just that that there hasn't been enough to prove they are true. Example: what trials? Where? Lowest winter temp? Complete dieback? It's quite exceptionally rare for any hydrangea macrophylla to bloom on new wood from the ground. Plants Nouveau has claimed that, at minimum, some of its hydrangeas can bloom on new wood. In addition to Revolution, the claim has been made for Noblesse, Pearl, and Garnet.

Revolution itself is a naturally occurring mutation of 'Xian' a.k.a. Opal. Mine was outside all winter and has not bloomed while its neighbor Pistachio is loaded. The description and patent for Xian have made no claims about new wood blooming. Others have complained about Revolution itself not blooming after winter, although mine (two) will be tested personally.

And re: Quebec residents... Snow cover can play a huge role in winter stem survival, because it acts as both an insulator and a windshield. This would lend to success in what are known as microclimates.

BTW, you can't go wrong with an arborescens or paniculata - if you like whites. Winters can't harm them, and they're otherwise quite hard to mess up. With macrophyllas, it all comes down to a) what colors you want b) how well you think you can protect them and c) how badly your winters will affect them.

And this is where the forum is most helpful. Many people here including myself think they're worth the risk of trialing and tweaking for reliable results, as well as weeding out the dud plants. And there are always more tricks to try. For example, my next one will be to lay 10-40-10 fertilizer under mulch in spring to replace excessive green growth with blooms. :)

So don't be discouraged with your recent purchases out there. They can always be better protected or used as a container plant if they don't live up to your garden standards.

This question is for True-Blue (or anyone else with similar experience that can help me) with regards to your mac growing in dappled shade under a giant maple....I have tried to plant macs about 10 feet away from the foot of a giant maple in my yard several times but have been unsucessful. Could you tell me how you are able to do this when I have not? Thx.

Different types of maples have different root systems: small versus large. Some maples' root systems are deep, while others -like the Norway- are shallow, right below the surface. That last one can be a problem.

Starlight I grow 3 hydrangeas at varying distances from the maple: 1 arborescens (6 feet), 2 macrophylla,Twist n' shout 9 feet, Endless summer 13 feet.

The tree is in my neighbour's front yard and is seperated by their pathway from our yard, which is slightly higher 2-4 inches.

The maple's canopy starts way up. But the roots are all over the place, and unless we have major showers no rain can past that canopy.

H. arborescens is really big and continues to sucker all over the place. It is rarely watered in the summer. but it thrives.

However, both macrophyllas are water hogs. Mulched, mulch-less they drooped especially the 1st 3 years. Remember my soil is 100% sand.

In the first 3 years, I had to water it regularly. Sometimes every day (especially in heat waves) or every 2nd day. I just put the hose in it's crown and let them drink.

However, since this year, 5th year, I have to water it much less. Maybe once a week if we don't have any showers. The plants are healthy and flower.

Mine receive dappled light and some 1 or 2 morning sun. And the one that receives the afternoon sun hates it.

In retrospect, if I had amended my sandy soil properly with organic matter, I might have a had a better result.

SG the worse year with the hydrangea was a freaky one when the snow melted in mid March and then we had a freakish cold weather -4 wind chills etc. That killed all the top buds.

Last year, during the polar vortex I couldn't cover the top buds of Twish and shout. Nothing happened to it.

From my experience it isn't the winter but a roller coaster spring that can kill the confused buds on the old growth.

Yes, the springs are the worst, because you're dealing with the tenderest of foliage and below freezing temps. In my experience, it takes a night of 28-27 degree Fahrenheit temps for a total of 3+ hours to severely damage growth. This will zap everything down to an inch from the ground. You can lose up to a whole month's progress, especially if the plant breaks dormancy in March. In any climate, it's most ideal if they break dormancy in late April, in exact coincidence with last chance of frost.

There are also local "farmer's tricks" you can use. Where I live, if you can hear the call of a Baltimore Oriole, danger of frost has passed. This is 90+% accurate, even for planting annuals. This year, I heard it in mid April! If the Polar Vortex hadn't already killed everything above ground, it would've been a banner year as they'd just broken dormancy.

I tie the stems in fall. I've less stem damage than usual.

In spring, if we have frost or a cold snap and the plants have leaved, I cover the hydrangeas with burlap. It works fine.

Yep, either that or blankets. I never throw out old ones or sheets. They are stored in a plastic tub in my garage. Frost or freeze warnings, out come the blankets. Use rocks or bricks if windy.

... And that's the life of a hydrabgea enthusiast in zones 4-6. Happy gardening! :)

Thank you everyone for your kind advice above. My next question is that I now know that the maple is a silver maple with shallow roots. Which hydrangea can I plant nearby and how close can it be planted? Looks like only aborescent or macs or good choices for this site. I have Annabelle, Incrediball, Pia, Mathilda Grutches, Blushing Bride, Moonlight, Original, etcs....which would be most suitable? Thank you in advance again for your answers!

Starlight I'd go with any of arborescence variety. Go with Annabelle. Nothing fancy.

I don't recommend Macrophyllas as they need a lot of water in my experience, unless you can water them regularly.

I haven't had much experience with paniculatas. But I've seen established ones growing without any care.

Any plants needs 3- 4 years to establish. If you plant and want to forget about it, it won't work.

Good luck.