I am not sure a southeasterly exposure would be my first choice. Full on sun until midafternoon is a bit of a harsh environment for a bigleaf hydrangea, which would prefer to be in shade for at least the hottest part of the day (generally recommended to be sited in morning sun only, then afternoon shade). You may need to pay close attention to watering well to accommodate the stress of excess sun and heat, but it can be done, especially as you seem to have gone to significant effort to prepare this location before planting ;-)

When sited well and allowed to grow freely, Nikko makes a big shrub - 2 will fill that area completely in time (easily 4'+ tall and 6' wide). Another good choice is 'Enziandom', sometimes called 'Gentian Dome', which is considered to have the most intensely blue flowers of any mophead in appropriately acidic soil and held in a large inflorescence. It will get to a similar size as the Nikko.

In your zone I would seriously consider winter protecting these plants, as cold winters will kill back flowering stems, reducing both the plant size and its ability to flower well. If you do a Google search on 'winter protection of bigleaf hydrangeas' you should turn up various methods to accomplish this very necessary step.

I had to laugh when I re-read my post at the "heavily amended soil" bit. That bed was all lawn, which I removed with a long serrated knife. The previous owners of this house must have had a rock garden, or perhaps used rock as mulch, because I took out four wheelbarrows full of rock, in heavy clay soil. Then I rototilled and removed a foot of the remaining soil and added new soil, compost and fertilizer to a depth of two feet, as well as creating a semi raised bed. Roughly two weeks worth of work, and on a broken ankle held together by nuts and bolts! All that reduced to "heavily amended soil" lol.

i did a bit (ton) of research on overwintering them and decided on tying them into a column, placing a trash can with the bottom cut out over them, and filling it with wood chips. I know I'll be paying very close attention to the thermostat.

The Enziandom looks amazing, and apparently resists scorching in the hot sun. I may have found a Nikko replacement. Thank you gardengal!

"Endless Summer outperforms the Nikko Blue with far more blooms regardless of exposure."

Jon, your experience may be the exception to the rule :-) If you read back through the posts on this forum, you will find a great many gardeners that have had a lot of difficulty with any sort of reliable performance from ES. In fact, a good percentage consider this selection to be a bit of bust and does not at all live up to the promise of an 'endless summer' of blooms - most would be happy if they got any!!

I can't really comment personally one way or the other, as I live in an almost ideal hydrangea growing climate and ALL hydrangeas perform beautifully here.

In a 6x12' bed, you'll find that 3 Nikkos across the 12' will take up a good bit of it after time. I would plant them 3-4' from the rear. In front, some smaller lilies or hostas go fine and they are usually zero-maintenance. You can fill the smallest gaps with annuals or something smaller.

Nikkos and ES both have very good stem hardiness from year to year, especially once the root balls get bigger. The root balls hug the surface of the soil but can go down to a couple feet deep. In years 2 or 3, you might benefit from tilling the ring of soil just outside of the hole you dug for the original rootball, this will allow for expansion of the roots.

Also, buy big! Don't fall victim to buying starter plugs online - they take forever to mature, especially in native soils. Only buy starter plants if you want to try something that's new and you can't physically find it anywhere.

Mari, glad to hear you want to plant multiple hydrangeas. I like 'Penny Mac' as well good bloomer and strong plant. I have many hydrangeas in full sun. Keep an eye on them they will show you when they need a drink. Once you learn the water needs you can water before they wilt. Use a bloom stimulating fertilizer and follow the package directions. Have you looked at 'Blue Billow' this is a good performer as well. This pic is a row of 'Madame Emile Mouillere' in full sun. You can see far back some leaves are wilting. Visit our face book for bloom pictures, Of the Woods Hydrangea and Peony Farm.

I bought these bagged bare root Nikko Blues at Lowe’s on impulse. Only $7.

1. Are these just extremely young? No other obvious drawbacks?

2. I assume I need to amend my alkaline soil to keep the blooms (if I get any) blue?

Unfortunately I'm not able to post a picture of the bags.

But they are small- the size of bare root roses. With only 1 or 2 canes coming out of the top of the bag.

Hi, Are you in a growing zone that has no frost possibilities anymore this Spring? If so, get them planted as soon as possible. Otherwise pot them up inside. Provide over head light and a warm root zone if possible. I don't recommend messing with the ph of your soil to obtain a blue flower. Instead I recommend people enjoy the color nature provides. I would recommend a transplant fertilizer to begin with. After you have some growth switch to a bloom boosting fertilizer. Best of luck.

I would not recommend either the transplant fert or the bloom booster. Neither one is particularly effective (especially the bloom booster) and generally, newly planted stock of any kind is unable to process and assimilate fertilizer well and using it at planting time can be damaging.

Hydrangeas really require very little in the way of fertilization at any time.

ETA: If you want blue flowers and live where there is alkaline soil, plant your hydrangeas in a container. That way you can customize your soil mix to the proper pH for blue.

Would definitely prefer blue to pink, but in the end I will happily take blooms of any color.

I’m not sure why it’s called blue if the ph is what determines the color.

If planting in pots is the best way to go, I am tempted to halfway bury the pots in the bed I wanted the hydrangeas in.

Would cutting out the bottom to allow root expansion defeat the purpose of the pot for color purposes?

Hi, Good point on the name. Keeping that in mind check out the names that are assigned to paint, they also make no sense.

As expected there are as many opinions as their are gardeners. I will stick with my recommendations. The choice is yours. Best of luck and keep gardening.

"I’m not sure why it’s called blue if the ph is what determines the color."

All bigleaf hydrangeas would prefer to be grown in acidic soil conditions. And it is the aluminum in the soil that makes the flowers blue. Less than properly acidic soil conditions (too high a pH) tie up aluminum and make it unavailable to the plant and then the flowers tend towards the purply pink colors rather than a true blue. And even in properly acidic soils, if there is not sufficient aluminum available, the flowers will not be blue.

Some bigleaf hydrangeas have flower pigmentation that makes them less amenable to color changes due to pH. I would consider Nikko Blue one of those in that it will tend mostly to blues (often a rather pale, washed out blue). It is seldom ever a true pink, even in alkaline soils, but more of a muddy pink color.

"As expected there are as many opinions as their (sic) are gardeners. "

The info I provided on fertilizers is not just my opinon :-) It is science based and easily researched! If you understand plant morphology and how they process and use nutrients, it becomes very clear how so-called "special' ferts - like transplant fert or bloom boosters - do not work efficiently in the manner in which they are intended. Or better than any general all-purpose fertilizer. They are really just a marketing gimmick intended to sell more fertilizers

The only way to really know if your soil needs amending is to have it tested. Tested by a lab and not using a tester sold in nurseries. If and only then you can add the chemical that is missing. Adding 'all purpose' fert or specialized ones sold in nurseries is not only bad for your pocketbook, but bad for streams and lakes that your water table runs into. Save the money that you are going to spend on unneeded chemicals - and they are chemicals - organic or not - and put it into the largest plant you can find. You will be happier and the environment will be happier. Good luck and enjoy your Nikko or what ever you plant. All hydrangeas are beautiful.