PlantFiles: Bigleaf Hydrangea, French Hydrangea, Mophead
Hydrangea macrophylla 'Nikko Blue'

I got four of these plants in 1997 when doing some re-landscaping. I have moved them around the yard trying to find a spot they would be happy in. They seem to like bright shade. They grow well but flower poorly in my zone 5a. I dump a bag of peat moss on them each winter and it helps, but they still only put out a few flowers. and the leaves are often chlorotic which is a bother to deal with.

I love this plant! I bought it in spring 2008 not knowing it will not flower in my area (Akron, OH, Z5) without protecting in in winter. After reading many sites I decided I wasn't going to dig my 5 plants out. I read about tying up the branches and then covering with burlap and mulch but the problems many people report are that the ends that carry the buds could be damaged or broken off even when inside the bag.... the snow could also put pressure on them or the wind could rub on them through the wrapping. I decided to go with a method I found on http://www.hydrangeashydrangeas.com
This was on the website:
[AN UNUSUAL WAY TO PROTECT HYDRANGEAS - FLATTEN THEM !
NOTE: As with several techniques on this site, I can neither recommend the following technique nor take credit for it. But it is such a wonderfully creative and unusual idea, that I wanted to share it with the visitors to this site. This is a highly unconventional way to protect hydrangeas sent to me from a Canadian visitor to this site (Maria).
I can give you no more information other than what you will read below. Basically, Maria describes how she flattens her whole hydrangea plant beneath sheets of cardboard and bricks. Maria writes:
"I live In Ottawa, Ontario Canada, and have been a very crazy hydrangea fan. In my very large previous garden I had quite a large collection of them. I was told by an old German lady that owns one of the nurseries here to cover hydrangeas this way, and it does work.
Find a middle of the shrub, gently push down each side of the plant (groups of branches) towards the ground, cover each with cardboard. (hunt for large TV boxes). When they get larger, I need help to hold them down. I use bricks to hold down the cardboard, then I put leaves over it all, and then white insulating cloth, and finally more brick to hold it all down. Later, the snow helps to push the whole thing down,.. and it has worked for me in this climate. love your site, Maria"]
Well I tried this method by staking all stems down to the ground and covering them a layer of leaves and cardboard in October and uncovering them on Mothers day (last day of frost for my area). Besides losing a few buds at the tips (remember they are very fragile) when I was uncovering them it looked like the old wood and buds would make it. They looked very white from being covered for so long. When I unstaked the stems they all bounced back... you could never tell they were flattened at all!
Well it is June 8th now and I have two huge blooms on one plant already in great pink color and many, many more to come on all the rest!
I will post picture as soon as I can!

This was given to me as a gift 10 years ago...purchased AT White Flower Farm which is in our home town so it should bloom here, right? (NW CT zones varies from road to road).

I heard that I should gently tie the stems all together so that the weight of the snow and ice doesn't flatten them and harm any buds. Did that and covered it with burlap. Moved it to a snug little corner to get nearby driveway and house heat....

This is the first year I've seen new growth on old wood but I don't see any signs of bloom buds...is it too early? Maybe I'll try a "cage" of leaves next winter and pine bows. Thanks!

I have had success in MN with 5 mature beautiful plants. They are quite large, approx. 4' high and bloom on old wood every year. The blooms are pink because I have not attempted to fertilize for the blue color. However, this zone requires that the plants are well mulched in winter. I cover the plants with straw and leaves (mostly maple and ash) all the way up to the top. They are located on the edge of my driveway so they also get covered with a good layer of snow from the clearing of the driveway which provides good insulation from our severe MN winters. I have not lost a plant in 10 years. They do tend to fade in the summer afternoon heat and sun, but perk up after sun moves away. This plant is well worth the extra care in winter and spring.

I was surprised to find this in a pot that I saved from the bulk trash pick up. It was in one of three huge pots. It looked pretty dead. I've never had a hydrangea before so I'm just gonna wing it and hope I get a deal out of it. I pruned it back a good deal because it was a mess, and added some acidic plant food. Funny enough I found a plant tag on one of the dead branches. Good thing or I might have just chucked the whole mess. And now I know what it is and how to prep it. Hopefully, I didn't prune it back too much to get a bloom this year.

I have a Nikko Blue hydrangea and finally found a way to mulch it enough to get a minimal amount of blooms this year. I weaved what seemed to be dozens of pine boughs through the bare stems of the hydrangea last fall being careful of the flower buds forming and then added almost a bale of straw intermingled with the pine boughs and tucked the straw underneath it to the base of the plant. My bush is about 4' tall and 5" across. I had 9 blooms this year. However, I found another gardening website that shows a cage that you can construct and then fill with oak leaves or insulation materials that won't pack down. I think I might try that one, too. Until it all becomes a massive chore, I'll try anything to get more than just a few blooms.

I have four of this variety, two blue and two with more of a pinkish lavender cast. They aren't totally wild about the heat here, they get a bit droopy in the afternoon heat, but bounce back to normal after it cools a bit. They are beginning to settle in and seem to be satisfied with watering every other day.

This hydrangea is one of the happiest growers in my garden. Great new growth during the first year and very well established by Spring of third year.

This year however, we had the need to move it to another location where the plant receives morning light. Previously, the hydrangea received 4 hours of direct sunlight during the hottest time of the day and really caused the flowers to droop.

Wish our hydrangea and us luck with our new location!

In my experience, an important key to success with Nikko Blue is the location in which you plant it. I planted some on both the north and south sides of my house. The north side receives some sun until about noon, and the south side receives no sun, thanks to some very large trees. I expected they would do better on the south, due to the increased shade, but to my surprise, the north side plants were MUCH more successful. I believe this is due, in part, to the protection from the hot, summer winds that blow from the south.

Also, I believe that if you live in a cold winter area (I'm in zone 5b), it is important to provide winter protection by piling leaves over the plants in the fall. I first did this in the fall of 2004, and was shocked in the spring. The plants sprouted from the previous year's stems and went on to produce triple the number of blooms I had seen in the past.

I really hate to say I don't like this plant, but if you are growing it in my zone5a it is an accent plant at best - not a specimen. It has way too much winter dieback and few flowers.

Planted in 2003 it did well from the nursery and in the following year; a late killing frost this spring killed back all the new buds on the old growth. But the plant survived and started to regrow from the base. By the end of June we had a half dozen large blooms. So it will definately bloom from new growth.

I originally planted a couple of these plants under an oak tree. No matter what I did, I could not get it to thrive among the oak roots (as said earlier by another member). But this year, I built up a large raised bed around this oak tree, and this plant is just going wild, loads of beautiful blooms.

I am in Zone 3 and I planted Nikko Blue in 2002. Everyone told me it would never last in our climate but I planted it on my south side between my house and my neighbour's where I have a little microclimate. I love the blooms. I also have Pink Diamond, Unique, Annabelle and planted Endless Summer last summer.

I bought 2 Nikko Blue in 1 gal containers 10 years ago. They have bloomed more beautifully each year, and continually self layer and create more plants. I now have at least a dozen plants from the original 2, and have moved them around many times, and have never lost one to transplant shock. I have just started intentionally layering to increase the number of plants and will have several dozen soon! I have always been enchanted with these huge true blue blooms and delight all my neighbors with huge sprays of flowers as gifts thoughout the summer. The flowers last at least a week in a vase.

I purchased a Nikko blue hydrangea and planted it in spring of 2002. Unfortunately, receiving bad information, I over-fertilized it with aluminum sulfate during the summer and almost killed it. It was touch and go for a while, but it survived. I mulched it well for winter 2002 but in 2003 did not have any blooms whatsoever. I thought perhaps it was still recuperating from the trauma the year before. It was suggested to me (fall 2003) to cover the bare stems with leaves over the winter in our area for extra protection (Zone 5b), so I did.

In late summer,2004 - just when I'd given up hope of it blooming - it suddenly sprung a small but very beautiful blue bloom - just one. Of course one of my friendly deer population ate it before it ripened to be cut. But I am hopeful that with good mulch, and a covering over the winter this year, I will have many blossoms next year.

Notes on winter covering: I was told originally to cover my hydrangea with fallen leaves in fall 2003. In addition to my bigger Nikko blue, I had also been given several 1-year-old plants by a friend that I also mulched this way. While this covering probably allowed the larger plant to come through one of our most severe winters on record (2003-2004) with prolonged temps of -25 to -20, the smaller plants died due to some type of cut worms eating right through the main stems. So I would not suggest this type of overall mulching for young plants. I am trying an alternative approach of using evergreen boughs placed among the bare hydrangea branches this winter instead of leaves. I had great success with placing the branches of our discarded Christmas tree over several small hydrangeas last year - they came through the severe winter wonderfully. If cut late enough (and with snow cover) the needles stay green most of the winter.

Put out nursery stock in May 2003 and it bloomed well last summer. Seems to tolerate Oklahoma heat well as long as it is watered every other day unless there is rain.

I was given H. m. 'Nikko Blue' as a rooted cutting many years ago from a distant friend. It flourished and gave me cuttings and bloomed well and grew to nearly 4' tall and wide. It responded well to cutting back (needed to keep a path clear) and definitely blooms on the same season's growth. In a place with short summers, I would advise pruning in fall.

When I moved, I brought a rooted cutting with me of course. It did not like being in lots of oak roots, but it sure likes the move to a more open soil!

I am in zone 5a and have grown Nikko Blue for over 20 years. It likes morning sun and profusely blooms big, beautiful, blue blossoms year after year. It does not tolerate late afternoon sun.

This shrub, sold by the thousands in cold climate areas, is not reliably winter-hardy in zone 4 or 5. It blooms on old wood, and therefore will not flower in the North, even though it is root-hardy through zone 4.