Hydrangea blues that is!
Hydrangeas are my favorite flower and shrub, a passion I inherited from my mother! And while I am fine with the traditional blue, as I expand my hydrangea landscape, I’ve attempted to introduce some other colors, such as whites and limelights (successful) and pinks (unsuccessful).
My lack of pink hues in my macrophylla hydrangea collection reminds me of a close friend whose first four children were boys. When she became pregnant a fifth time, she decided to wear only pink for the entire pregnancy! In her first trimester she was told to expect twins. She adored her sons, but I think the trains, trucks, footballs, baseball bats and dinosaur decor had run its course. She wanted that pop of pink! She wanted to introduce Barbie to Spiderman! But, what popped out were fraternal twins-two adorable baby boys! She was delighted. She was in love. Her passion for pink did not linger. She saved a fortune on baby clothes and toys, and she’ll certainly save a fortune on weddings!
But I empathize with her when it comes to my blue hydrangea children. I adore their show-off blue audaciousness and rock-steady performances. Although I turn to other flowers to contribute pinks, roses and magenta hues in my landscape, I must confess: I too, yearn for that early pop of pink in my macrophylla hydrangea family!
The failure in pink is all about my soil chemistry. Here along the Delaware coast, USDA Zone 7b, my soil has a good deal of aluminum composition and as a result my pink purchases eventually turn into blue boasters! And I am fine with that! But I keep trying, thinking my soil’s chemistry will change all by itself.
I fell in love with a particular hydrangea below (left). Its old-fashioned look and combination of pink centers and creamy white edges reminded me of something my grandmothers might have selected. I quickly scooped it up in my garden center cart and made a bee-line to the checkout counter. I planted it in a special location–at my garden gate entrance where my visitors and I would not miss this unique greeting. For the remainder of the summer I enjoyed the variegated pink display. It was a great choice as the official welcome hostess to my garden. I looked forward to it growing profusely offering delicate pinky goodness in my landscape and bouquets!
I should not have been surprised, but I was, that my soil had a different plan in store for that shrub. The following year not a trace of pink remained. The blue bully lurking in my soil battled for dominance and won, replacing all of the original, dainty pink hues. To the victor goes the spoils! I am a gracious loser!
While the colors of some hydrangeas varieties are affected by pH, that is not the only factor. Your soil’s pH will affect the uptake of nutrients and minerals that pre-exist in the soil. With hydrangeas, it is the uptake of aluminum that is the primary factor for color.
If you have pink, and want blue, it’s easy to add aluminum to the soil if it is not there, and make your soil more acidic.
But if aluminum is already in your soil naturally, it’s much more difficult to remove, and simply changing the pH toward alkaline will only slow down the plant’s ability to access that aluminum. But it will not be enough to override the blue. This Georgia Extension site explains it. A good deal of misinformation and Old Wives’ Tales on changing color abound on the Internet. My mom told me pushing pennies in the soil would change, or boost the color!
Another way to explain how it works is to think of your soil pH as a straw. Acidic soil would be a very wide straw, allowing the plant to uptake its mineral needs, and therefore turning pink into blues or purples or violets. Alkaline soil would be akin to a very narrow straw, preventing the plant from accessing those same minerals, therefore remaining pink. If the aluminum sulfate and other minerals are already in the soil, it’s easy to change the size of the straw. But those minerals have to be there, or be added. It is next to impossible to remove minerals, which is what one needs to do to get the pink hues. But you can try to reduce access to those minerals by narrowing the straw.
Some soils have pockets of alkaline and acidic qualities. Rarely is your soil consistent across your property. Soil’s with these characteristics, combined with an unknown history (did a structure exist on the spot sometime in the recent or distant past?) That might account for a pH or metallic anomaly. Neutral pH can be a delightful blessing providing the hydrangea owner with blues, pinks and purples from the same plant. Roots spread in all directions so who knows what they’ve tapped into!
The plants I buy purposely as blue are normally not as beautiful as the blues that start out as pink and transition over to blue. Those chameleon blues are stunners! The flower below, was a deep pink, hot-house hydrangeas with blooms forced for the Easter market. I planted it that same year and it stopped blooming, which I expected. For an additional two years it grew and leafed out and did not bloom. But on the third planted year, the shrub, nearly 5 foot tall, was festooned with these beautiful blue balls with just a whisper hint of lavender! Why its more blue than any of the blues I bought as blue!
In July 2017, I bought another hydrangea (because one can never have enough and I am completely justified since I suffer from GBTH (Gotta Buy This Hydrangea) Syndrome–a serious affliction for which I am refusing treatment! My husband, however, has tried many forms of intervention upon me, alas (hooray) to no avail. I google-eyed and exclaimed “ooh la la” over a specimen and eventually bought the “Merritt’s Supreme” looker, seen below. The garden center owner assured me it “should stay” pink. Even without this expert assurance, I was going to buy this showy darling! I heaved her my trunk for the short ride home (yes, I refer to it as a she). Here it is where I gave her a new home:
Miss Merritt is leafing out now and setting her 2018 buds. Other than adding home-grown compost at planting, I’ve not added any fertilizer or amendments. I resolved to let nature take her course. Stay tuned for the June reveal!
UPDATE: June 17: We’ve gone purple! I love the color shift.
In 2018 I don’t have as many blooms. The spot I selected clearly gets more shade than what my Merritt’s Supreme obtained at her nursery. We’re going to do some strategic tree pruning, and take down one Arborvitae that is not doing well, and that should allow more light to filter through and improve the flower yield of this shrub for 2019. But look at this violet color!