I live near a small botanical garden that houses an amazing array of ornamental plants, including a significant collection of rhododendrons. The majority of those plants are grown with great deliberation and care, but one of the most amazing seems to have sprouted of its own volition near a boundary fence. Over the course of this past growing season it has made an aggressive reach to the heavens, becoming increasingly visible to viewers inside and outside the garden.
The mystery plant’s leaves are enormous, like 14-inch green saucers with shallow lobes. An entire family of toads—or even rabbits—could shelter comfortably under a single leaf. Each one is slightly fuzzy, or tomentose, as the botanists say, and pairs of them adorn woody stems.
Since the spring, the main stem has grown approximately seven feet—a phenomenal rate of growth that puts the mystery plant on par with some of the giant annual sunflowers.
Clearly though, it is not a sunflower.
Every time I passed the mystery plant in the summer and early fall, I vowed to discover its identity. Until this past week, my good intentions deserted me before I got home. Finally though, the mystery plant and the riddle of its identity grew so large that I couldn’t forget them.
After a bit of research I made a positive identification. I had been tantalized and stymied by a young princess tree or Paulownia tomentosa.
As far as I know, the Paulownia in question did not bloom last spring. If it had, I would have known it by the flowers, which are lavender and white, borne in large, pyramid-shaped clusters. The individual blooms resemble foxgloves, and smell like vanilla. A paulownia in flower looks a little like its distant relative, the northern catalpa tree, which also boasts extra-large leaves. Plant taxonomists have played fast and loose with paulownia, assigning it to the Bignoniaceae family, along with catalpa; then moving it to the horrible sounding Scrophularaceae to keep the foxgloves and snapdragons company. Now the foxgloves have moved on botanically and so have the paulownias, which have acquired their own plant family, eponymously called Paulowniaceae.
I think plant taxonomists, while scientifically astute, take a kind of sadistic glee in tormenting and confusing gardeners.
All of that matters little by comparison to my glee in unraveling the identity of the mammoth-leafed mystery.
As the locals sometimes say, paulownias are not from around here—and “here” means the Americas. They hail originally from a region running from western China to Korea, and made their way to this country by 1834. Then as now, I am sure people were fascinated by their fast growth and entranced by their flowery magnificence in spring.
I think my mystery paulownia was self-sown because it was growing right next to a fence—far too close for a tree that will end up being about 40 feet tall and equally wide.. The unlikely self-selected location is indicative of another paulownia trait—fertility. According to woody plant guru Dr. Michael Dirr, a large paulownia can produce up to 20 million seeds per year. Under ideal laboratory conditions, 90 percent of those seeds will germinate within 19 days. Even without ideal conditions, that means that paulownia has a strong tendency towards invasiveness. This is especially true in the mid-Atlantic and south central regions of the United States, where it escaped early, reproduced prolifically, and is deemed invasive.
This does not stop paulownia’s use as an ornamental in some situations. Longwood Gardens in Kennett Square, Pennsylvania, used to have an impressive allee of paulownias, which, I believe were installed on the orders of founder, Pierre S. DuPont. I have not seen it in my hometown, except naturalized in a railroad right-of-way, and, of course, sprouting up on the edge of the nearby botanical garden. Given the germination rate, it’s a wonder there aren’t more of them.
So… I solved the mystery, only to find that the lovely, mysterious plant is tainted by villainous ways. So many are—common violets, purple loosestrife, multiflora roses, to name a few. I won’t aspire to plant a paulownia tree, but I will cling to higher hopes for the next mystery plant. With luck it will be a worthy, non-invasive ornamental, not a wolf in foxglove’s clothing.