One of the innumerable joys of May in the Botanical Garden is the paulownia, or princess tree. People are immediately attracted to their huge, velvety-hairy leaves, stout stems and the ridiculously rapid growth they exhibit as younger plants. The leaves and stems on reproductively mature plants are more restrained, and the large fawn-coloured overwintering buds and flower stalks are conspicuous on the bare stems in winter. Paulownias are reputed to be among the fastest growing of all temperate deciduous trees, but in parts of North America where summer moisture is reliable, the common princess tree is considered an invasive species. Not here, thankfully, and the reason is probably a simple one: our ever-deepening summer droughts and increasingly soppy winter conditions effectively conspire to limit both seed germination and seedling establishment if seeds were ever to spill into wild areas.
Our largest paulownias, Paulownia tomentosa var. tsinlingensis (Quinling princess tree), are located along the fence that separates the David C. Lam Asian Garden from Old Marine Drive. The species is named for the Quinling—pronounced chin-ling—Mountains, an east-west range that runs across central-eastern China. Technically outside the Garden, our trees are conveniently close to the Ting (the lookout at the end of the boardwalk). Here, in May, the conical clusters of mauve and white foxglove-like flowers are both easily viewed and close enough that their sweet, violet-scented perfume can be detected. A somewhat more intimate experience can be had with the related Paulownia kawakamii (Taiwan princess tree), which has deeper, purple-blue, startlingly beautiful flowers. This species, also known as the sapphire dragon tree, is considered critically endangered because of habitat destruction in its native Taiwan and southern China. Also in this area is Paulownia fargesii (Chinese princess tree), a valuable, fast growing timber tree native to the mountains of southwestern China and adjacent Vietnam. Our specimen has very large, but comparatively pale flowers. These two species are located nearby in the Peter Wharton Cherry Grove and both have flower-bearing branches close enough to the ground for visitors to investigate the buds and flowers. Although renowned for fragrance, not everyone can smell paulownia flowers. There is evidently a common mutation in a human “odorant receptor gene” that underlies the sensitivity to the smell of β-ionone, the compound responsible for the aroma associated with violets. (For those interested in the science, here is a link to an explanatory article).
A third significant location for paulownia is the Forest Theatre in the Asian Garden, where there are no paulownia trees. The wooden benches are, however, constructed of paulownia wood that was derived from a 2019 storm-toppled var. tsinlingensis tree. The choice of paulownia wood for the Forest Theatre was easily made. The local arborist who handled the blowdown kindly offered to mill the timber (in our parking lot), and UBC Forest Science was able to kiln dry and store the lumber until it was needed. Fortuitously, the landscape architect was delighted at the opportunity to incorporate on-site material into her design. Equally important to our decision was the tradition of using paulownia wood in Asia. The wood of all species is highly prized for its workability when freshly cut, and its hardness and resilience when dry. The timber is variously used for cabinetry and the manufacture of musical instruments and dowry boxes, and in Japan, P. tomentosa is used for making geta (traditional elevated clogs).
While you’re having a seat on the paulownia in the Forest Theatre, don’t forget to admire the slug-free Meconopsis Fertile Blue Group (blue poppies) in the large copper-tape rimmed, Corten steel boxes all around. The poppies will be blooming through much of the month. For these we have Millie Kermode to thank. Millie was a long-standing Friend of the Garden (FOG) and garden donor who was convinced we were diminished as a garden by not having a display of blue poppies. She remembered scores of them gracing the Botanical Garden decades ago (when slug poison was routinely and liberally spread around). Nowadays, our live-and-let-live (no pesticides) policy makes cultivating these Himalayan beauties a virtual impossibility—or at least impossible to have them with flowers and leaves intact. And this was the message we took to Millie, but she insisted that we find a way. And Andy Hill, the Asian Garden’s Curator-Horticulturist did find a way, with two broad strips of copper tape around the rim of a steel box filled with rich, moisture retentive soil. No slugs are harmed, but the small electric current created when slug mucus reacts with the copper is sufficient to deter these mollusks.
UBC Botanical Garden is more than just a collection of plants. It’s people working together to create a biodiverse, enticing and enlightening place of beauty and wonder, where natural and cultural histories are cherished and built upon. Visitors might not realize it, but every flower, plant, trail name, steel box and timber bench in the Garden has a story to tell.
Written by:
Douglas Justice
Associate Director, Horticulture and Collections
UBC Botanical Garden
UBC Botanical Garden
