Late-blooming lilac changes color

I’ve written before about Miss Kim lilac, the late variety that opens its flowers long after the common lilac is finished blooming.

But this season my Miss Kim has done something strange. It has seemed to change the color of its flowers from pale lavender to white over the course of one season.

I commented to the husband just a few days ago that Miss Kim was different this year.

”Who is Miss Kim?” he said.

So I told him the story of the Korean lilac, Syringa patula ”Miss Kim” and how I planted it below a window so its fragrance would carry through and into the house. I told him that the shrub had always bloomed medium to pale purple flowers nearly every year.

And then I realized that not only were there white flowers on Miss Kim but there were a lot of them. Many more, in fact, than I’ve ever seen in the nearly 10 years since I first put this plant in the ground.

Not that I’m complaining. I love seeing this shrub so full that her branches are nearly bending over offering a waterfall effect. I don’t even mind all that much that they are now blooming white. I am just wondering why.

I know that Miss Kim is temperamental about her watering. Too much or too little and there won’t be flowers at all, which is why I planted her at the top of a slope where the pipe from the roof gutters run underground from the corner of the house. She can get plenty of water on rainy days, but it will drain quickly so her roots aren’t sitting in a quagmire.

The shrub also is particular about her fertilizer, too much and once again, no more flowers.

But lack of flowers isn’t the issue. Changing color isn’t as common in plants – most plants, that is.

Many hydrangea varieties will change flower color depending on the PH of the soil. Acid soil will produce blue flowers while alkaline soil turns them pink.

You can literally change the color of your hydrangea blossoms by adding aluminum sulfate to the soil if you want them to be blue or by adding ground limestone if you want them pink. In some soils the soil PH varies from spot to spot, which can result in shrubs with both pink and blue flowers, or combinations of the two.

If a hydrangea is planted too close to concrete, they can turn pink as the concrete residue leaching into the soil raises its PH.

Not all hydrangeas have this quirk, however. White hydrangeas, such as the old-fashioned variety, Annabelle, aren’t affected by soil PH.

Miss Kim is planted near the concrete foundation on that side of the house, and even though she is a lilac and not a hydrangea, it could be possible that a change in the soil could affect the blossom color.

While I contemplated the change in Miss Kim’s appearance, the husband made an interesting comment.

”The tree in our neighbor’s yard,” he said, ”half of it is purple and half of it is white.”

And he’s right. My neighbor had asked me about his strange tree, an Eastern Redbud, a few years ago and my first response was that there were actually two trees growing closely together and they only looked as if they were one tree.

But he said that wasn’t the case. He had looked closely at the tree and it was obvious that the two leader trunks, each producing different colored spring blossoms, were branches from the same main trunk. So I explained that the white half of the tree had probably originated from below the graft and was likely the offspring of the original rootstock.The tree that was intended was likely grafted onto the roots of a stronger plant when it was just a seedling.

The reminder of our neighbor’s tree made me realize this could have happened to Miss Kim, but I still have my doubts.

Miss Kim’s change happened seemingly overnight, or at least over the course of one growing season. I swear the flowers were purple last spring. Had it been a rootstock issue, the change wouldn’t have been quite as sudden.

I never knew a lilac could be affected by soil PH, but if it can happen to a hydrangea, why not? I suppose a soil test is in order and perhaps the addition of a bit of aluminum sulfate to bring back her natural beauty.

But then, I sort of like the white.