Notes from the Garden: My Heirloom (and Mysterious) Bridal Wreath Spiraea

Many years ago, on a farm located on the Salt River in Mercer County, Kentucky, my maternal grandmother planted a spiraea.  It blooms early in March, sometimes the delicate white blossoms even appear in a mild February, and blend in with snow on the ground. My mother took a division from this shrub and planted it on the farm she moved to (on the wrong side of the Kentucky River, as I’ve heard her grumble before). Around 10 years ago, I dug up a tiny bit with roots, and planted it in the narrow backyard of my 1925 bungalow in Lexington, Kentucky. When I moved again, I brought it with me.

My bridal wreath spiraea, March 2024.

It’s a glorious, untamed, spreading shrub, perfect for my preferred cottage garden aesthetic. But I’ve always been puzzled when discussing it with other gardeners, because it looks nothing like what other people call a bridal wreath spiraea.

Two of the original spiraea sat on either end of the sidewalk at my mother’s family home, seen here in the 1950s.

Spiraea (the genus) is a deciduous flowering shrub, and the name originates from the Greek word, speira, or “wreath” in reference to the orientation of the shrub’s delicate flowers.

My amateur efforts at identifying my beloved version research yielded more confusion. I thought it might be Spiraea prunifolia, but the leaves and blooms aren’t quite right. I’ve also dismissed Spiraea × vanhouttei as a contender.

Detail of my spiraea.

The blossoms on my spiraea (which is now around nine feet tall and nine feet wide, after six years in its second location) are delicate, unaccompanied by leaves, and not clustered together in little clumps. I believe those clusters are called umbellate clusters. My spiraea also blooms a good month before its more blowsy, strident (yet still beautiful!) cousins.

The “other” spiraea.

I have some of those blowsy kin, and they are blooming like mad right now. I’ve found them across Kentucky, both at historic farmhouses and in town.

The flowers of the “other” spiraea.

The leaves of the two shrubs are also quite different.  The leaves on my spiraea (#2 in the photo below) are longer, and appear after the blooms. The stems are darker as well.

My spiraea is #2. The more common spiraea is #1.

Head scratching continued. Could it be Spiraea x arguta? This seems like a better match than the others, and interestingly, this looks to be a popular variety across the pond in England! Spiraea x arguta is a cross between S. multiflora and S. thunbergii. It does not appear to be a widely available nursery plant, but I did find a reference to it in a 1912 Bulletin (number 21) put out by the Arnold Arboretum at Harvard University.

A description of Spiraea arguta from Harvard University’s Annold Arboretum, circa 1912.

I would love to find it in a garden catalog from the 1940s, which is when I suspect the original shrub was planted by  my grandmother. I imagine she didn’t buy a shrub, but instead, planted her own divisions from another shrub, from a garden somewhere in Harrodsburg. The species name is irrelevant in the end, as I adore my beloved heirloom shrub no matter its proper classification. My heart lifts when its blooms begin to show early in the year, as we turn our tired faces from winter.