Hmmm, tough question. ... The height and width given on plant labels and in ads are estimates by the wholesalers/hybridizers,,, guesses of "more than 5 years".

But please understand that there are many, many factors that interplay for a particular variety to reach a certain height/width in one particular location and that the same result may not happen everywhere or even close-by. What works with one rebloomer may not "work" with another... even in places close to one's home. Consider two people living close, say about 100 miles or so; if one variety is planted in sandy soil by one person and another person plants it in clay or loam soil. Just an example that even close-by locations can have different growth rates.

If your location has a long growing season, the plants can grow more and faster and reach those estimates sooner than otherwise.

Then adjust for local weather, sunlight, micro-climates, moisture and type of & minerals in your soil. The more favorable these are, the happier the shrub will be and the faster they will grow.

Then there are genetics. Genetics may also play a role in how fast one variety grows. This one makes paniculatas (for example) grow a lot per growing season and makes a Let's Dance Series shrub (mophead) grow more slowly.

Also, some hydrangeas may start slow and take about three years to produce
high growth rates. Part of that is because it takes them time to become
established. The roots in the plant pot are small and it takes them a
while to grow more extensive root systems.

Finally, consider that plants do not typically just stop growing when
I get to the height in their label. They do keep getting bigger, albeit
more slowly in some cases.

The best suggestion that I can offer is to post the names of the varieties that you plan to get and ask people near you to chime in; then pay attention to replies by individuals in very close range (100 miles? etc?). Ask these persons to post what their experience has been for the varieties that you want (for example: the Pistachio Hydrangea has grown to "x" feet high and "y" feet wide in "z" years from an original height of "a" feet and width of "b" feet, etc.).

I hope this helps.

Luis

PS - look what I found! now we just need to add the hydrangea!!!! Ha! ;o)

https://www.amazon.com/Gallon-Grow-Plant-Fabric-Planter/dp/B076Q4GMZN/ref=sr_1_1_sspa/144-3460238-9921047?ie=UTF8&qid=1517289098&sr=8-1-spons&keywords=25+gallon+pot&psc=1

Where I am, the rebloom on the reblooming macros is so sparse and so late in the season that it's barely noticeable if it happens at all. So I personally would never rip out older established macros to replant rebloomers.

However, your mileage may vary based on where you are located. Where is that, by the way? I know other members of the forums here have asked you this question repeatedly, and have tried to get you to update your profile with that information so that we can better answer your questions.

Profile has been updated a long awhiles when you click on it. I'm out in the east end of LI.

Do older macros change in behaviour in bloom. Granted, my issue is moreso due to former HO neglect so due to largish canes/root flares, new growth interweaving between spaces of thick hard wood is very hard - and if so, they don't make it high enough before they dieback.

Last year was the breaking point as a good majority had only a handful each. Bad analogy but 5 blooms for a 5' round sphere.

I've been observing these older ones super critical this year/last to help me decide if I'm going the R/R. Sofar, what's I've noticed on the oldest ones is that the terminal buds don't seem to last at all, whereas plenty of the sideshoots are fine. Going to see how my many canes dieback or not come spring.

Oh, I'm sorry! I didn't see that.

Here's something you can do to make it more visible:

Go to "Edit Profile".

Under "Profile Sections", choose "Advanced Settings". Scroll almost to the bottom of that page, and there will be a box that says "Climate Zone for Garden Forums". Just write it in there!

As for old canes on macros, your zone must be a lot more favorable than mine is. I never see canes develop long enough to get significantly woody.

I've been wondering about canes vs. stems too....aka, I planted a couple of small let's dance. new small hyra's are more like a shrub with branches, etc. To compare, old established ones are more just straight vertical shoots of canes, that don't grow side branches

Is this more due to age and establishment, or more a cultivar thing, and these newer breeds of Hydra's will have branches and such.

LOL Luis. I meant 25G nice handsome pampered nourished hyras ready for sale. I would don't mind buying large shrubs rather than playing the wait game.

I got a client who's got deep pockets. I can't recall the exact figure but he wanted a tree in a specific spot in his garden. This tree was no baby tree by no feat. I think he used a tree broker. He paid like north of 75K for the tree.......or was it 120K. Anyhow, I could not wrap my head around it.....

Gardening is just one of those things where it can't be rushed... You're basically at the mercy of time. Heh, that is why medium/large shrubs cost $$$.-$$$$ Someone's got to pay for water if not space that it has taken up all through those years

Hi Luis, thanks for the post on the pots, found them interesting and the price is right(5pack) good reviews also

For fabric pots, I tend to stick with the original

https://rootpouch.com/

Hee hee hee. I know that is what you meant, a1an. I could not resist when I found the Amazon Link though. I knew there was a such a pot (without a hydrangea, of course) because years ago, I bought such a pot, filled with soil and with a Souvenir de la Malmaison Rose. Gooooooood, it was heavy! The prev owner had run out of space and was planting the shrubs in pots. All kinds of pots. I was looking for a (new) SDLM, unsuccessfully, and decided to finally get it there. Oh, I never got a 25G anything after that! LOL! ;0)

a1an what would you do with a 25g potted reblooming Mac it would be about 5’x5’ now you have to get it out of pot and plant it... need to Winter protect ...your back to sq 1 ( reblooming will/ may give you 1/2 doz. blooms if you’re lucky, I would go in a different direction.

I've got some large macs that has been neglected in pruning - aka, big canes, big trunks, big root flares. (I'm thinking these Macs are like 70+ years old) - based on my talk with my neighbor. New growth is hard to grow from all this *wood mass*. There literally is no space for new growth to weave through. The bottom has alot of older canes that have been cut down. There's area where the root flares are more like a mini stump cut flush. LOL, I did find one that managed to do a S around a cane to grow up. On one of the canes that snapped off due to the recent snowfall, I measure it. It was a hair over 5/8" thick !

Don't get me started with the trunkish canes where it's a small stub that is probably borderline 2 inches + .

In one weird area (and I'll try to grab a pic this spring) is right off the center, it's like a large wood root (and I mean large) that is all wood. It would be nice if some new growth could happen, but between that & older canes that either have died back, snapped or cut (they are all not flush to the ground), there literally is not room for new ~green~ to grow up from the bottom.

I've got some better maintained ones that has nice straw sized canes, thinned out to let news ones up, etc.

But some of these much older ones...hell, one of the canes that when I say is trunkish, I think is thicker than the trunk of the LL trees I've planted.

But some of the neglected ones, while its one big round shrub in the summer, I don't know if I really can bring it back to where I want from a pruning perspective to allow for new growth.

So in my mind, regardless of the rebloomer or not, I'm just thinking that that the ones with so much (wood) is not something I can really bring back . Am I making sense logically

a1an I hear you, pulling out 70yr old hys you’ll have to make that decision...last May I pulled out 3 ES that were about 12yrs.. had some great years with Winter pro but the last 5 (no WP) Very Few Blooms..

Thanks, Those canes look to be borderline 3 - 3 1/2 feet - 12 years. These full grown ones I generally prune to about 6 feet max, just to keep them managable as once it's summer, the leaves and all make it even higher.....

Uggh. Grrr. That's exactly why I've hesitated so far. Hard to replace biggies with pee-wees with always the unknown variables ya know. And yes, the push was this year with greens galore, and on one, a paltry 5-8 blooms

Those ES would top out about 5’ H 5’ W by Fall, with the new growth .. the IVS 11 will top out at about 4’ in a few yrs

hyed..in your pic above with the big buried rock..is the hydrangea on the right an arborescens?..looks good..little to no dieback..or if a macrophylla which one?

Is the 5x5 just a general broad term statement. Alluding back to Luis 1st response in this thread. I actually checked out Hyd. Plus site. Seems like most if not all the Macro's she has listed - the default size seems to be 5x5.

Mine can probably get up to 6 1/2-7 if I did not cut them back to about 5

With little ones now in the mix, LOL, I'm sorta okay with them being a bit shorter as then I can look out the kitchen window and scan the yard as they play !

Luis. Crazy story about the 10G Bloomstruck I overwintered in a 30G pot. It was warm the last 2 days so I decided to see if I could move it a bit....anyhow between the weather, the weight/size of the pot and water/temps, the bottom of the pot is frozen to the mulch.

I could not budge it left or right. I then proceeded to try to lift it.....18 inches past the diameter of the pit, the pot/mulch and frozen soil - all in one piece was lifting up. It was quite the sight. We're talking probably a 4 foot square of frozen dirt lifting up....

Needless to say, I left the pot alone....

a1an here is one of my ES about 5 1/2 X 7’ W

What time of year are you trimming your hydrangeas to keep them at the size that you want?

Wow, a1an, you sure got an unexpected workout... Even if you almost did nothing that you planned to do!!!

Nichols that would be a new Annabelle was going with pink, white pink and white

I guessed right!..Annabelles are so reliable aren't they?..yours look great..

Illstep. I usually trim around mid aug-Sept...but I don't trim them all each year. I do it ~selective pruning~. I'm losing the terminal buds which I'm OK with. I leave about 4 inches above a healty bud and wait until spring to clean up the tips to where the bud is.

In my mind, leaving a bit of extra wood on top might help the bud a bit in the elements. Terminals don't really last anyhow

snapped a pic of a snapped cane

5/8"+

Interesting Blurb blog from one of the local nurserys around me. Same/Similar statement on enchantress, nikko and ES

"It grows at a fast rate, and under ideal conditions can be expected to live for approximately 20 years."

Did they copy and paste or what am I amiss. My neighbor has been here since they developed/built in the area so my WAG on the shrub being 70 years+ is close. Where am I amiss where their blog is advising 20 years

I have had good success at dividing hydrangeas. Yes, dividing like a perennial. Try taking a couple of hunks off the larger masses of roots from the older plants. For some reason, this is not recommended by most nurseries or books, but works for me. We recently divided a 6 ft Nikko - about 25 - 20 years old and all 5 pieces are doing just fine. I did not cut them down very far - just took off the old blooms, and pulled and pushed and tried to keep as many roots as possible. Then, I washed the roots really well, untangled the ones attached and spread them out and put them into pots. If it stops raining here in the PNW tomorrow I will take some pics for you. I gave about 10 from other plants - Endless summer, Kluis Superba and Nikko Blue to the Seattle Volunteer Park last spring and they were done the same way. They made it through the winter out doors just fine - but remember, this is the PNW about zone 8b or so. The great result of this rather uncommon way of propagating is that the first year they are 4-5 feet tall - immediate gratification. I have also divided some smaller Japanese varieties. Don't worry about exposing the roots, the latest articles show that this assures the soil is all the same texture throughout the pot and the ground if planted directly. Compacted soil in the middle of the root ball and lose soil in the rest of the pot or planting site will kill the new cutting. Washing the root ball also means that you can inspect the roots and make sure there are no critters or that the roots are circling and not growing out. Dr. Chalker-Scott reports that this root pruning is as valuable as pruning the top of the plant.

Thx ophoenix. I have to picture what this would entail...meaning, let's pretend I divide it by 1/2 or a 1/3. Hopefully, the center canes that exists that is just wood short cut downs will eventually break away to let new growth. Ophoenix, have you seen these crazy root flares I am talking about. It's almost as big as a tree trunk root flare that is above ground. No new growth is coming out for this area just due to this mound of wood.

Then, let's pretend I recenter the new divided plant. Will it eventually grow back in a nice mound or will it look like someone took a ~bite of the apple~. Ha, just thinking outloud.

Cane height aside, will a younger shrub have more vigor to bloom than a older shrub at a certain point ?

Can you post clear photos of these "root flares"? This is not a common phenomenon with bigleaf hydrangeas but they ARE considered a suckering shrub so that might be what you are seeing. That attribute is also what allows them to be divided, which as noted is NOT a common practice with any woody shrub but can be accomplished with a caning, suckering shrub like a hydrangeas if done carefully.

btw, not sure what source you are reading but hydrangeas are typically very long lived shrubs when given the proper care. 50 years or more is not unheard of.

GG -

I'll grab a pic when the unburlapping happens. It's really hard to picture what is being described so I'm sure a pic speaks a thousand words. Imagine a large ginger root planted in soil - about 9 inches long and about 4 inches wide.. Kinda like that. Bottom line, the flare is so big and woody....literally , no new growth can come up, as there is no exposed/soil. Hence, I was suggesting that maybe it's beyond rejuvenation if the goal is to get new growth.

The copy-paste was from one of the local nurserys I frequent - their blog. I suppose it was just a terrible ghost-writer for the blog portion. When luis mentioned to see what was hardy in my local, I just went to their blog and keyworded - hydra, and the copy/paste of the lifespan was what struck me

a1an, I have no idea of what it is that you call 'root flares'. You have to be careful of what you believe that you read on line! Blogs, websites, and books must be judged on the merits of the writers. Are they real people, are articles just being posted to fill space on a site? What are the credentials of the authors? Are the sites sponsored and just there to sell products?

This forum has many respected, educated and experienced gardeners. But, if you look on line I am sure you can find an article somewhere that will refute everything that is discussed here. I do a lot of propagating hydrangeas and many other plants and am successful most of the time - if you want numbers might be as high as 90%! How? I read constantly, evaluate the 'experts' that are quoted and almost as importantly, I try many different ways to accomplish this. Tony Advent, Plants Delights Nursery, says 'he won't give up on growing a plant unless he has killed it at least three times.' That is my mantra.

The theory of plant propagation is very simple! Cut a piece, dunk in rooting product and put in planting media. As simple as the theory of playing the guitar. Get a guitar with strings, put your finger on the string and pluck it to make music! The actual process is a hell of a lot more complicated and making new plants and making music is very very intensive and both take practice, practice and more practice. You can ask questions for more instructions, pictures and techniques, but until you go out a actually dig up a plant, wash off the roots and figure out the next step, you will never solve the problem.

Heh. These RF that I speak of, I really got to share a pic. I literally was was all 4's crawling, observing the base, determining the cuts for the 1/3 rejuvenate rule, etc. Lots'a areas where I had to hold off on cutting to rejuvenate as it's so woody down below and not seeing any new growth.....

Dig up the plant! Wash the roots and then pull off - or cut off branches with roots. Keep the branches - the new growth will come from the base. If you are going to have cold temps - hard freezes, then bring in the new potted, rooted plants. Keep moist. When you have it out of the ground, you will be able to see where to cut for your 1/3 and will be able to cut off really old wood easily. You will probably be able to pull off some of the really old dead stuff. Cut the old wood as close to the root ball as possible.

LOL. I absolutely misinterpreted your OP on dividing. I would have literally loosened/dug up the entire ball, and just because it would so large and not manageable, I would have selectively just divided to size by just taking the transplant blade business end and would have sheared straight down here and there.

Now that your broken down the instructions again, I can see how by root washing and such, I can also selectively remove some of those older deadwood that exist as well.

I might need a helper or two to hold it up while I take care of the business end ;-)