The story of Dieter Trost’s dwarf birch
Perhaps you remember a margarine commercial from the '70s, featuring an elderly woman wearing a white dress and a crown of daisies. Told she is sampling margarine and not butter, she says menacingly, “It’s not nice to fool Mother Nature,” and unleashes havoc with rain, lightning and, yes, elephants (those kooky '70s).
Yet Mother Nature has no problem fooling us, whether it is desert mirages, green flashes or, for locals, the Oregon Vortex. Fortunately, some of us humans have a few cards up our sleeves as well.
Such was the case in Medford one fine day 45 years ago, when Mother Nature disposed a riddle on Dieter Trost, nurseryman extraordinaire and owner of Southern Oregon Nursery. In 1976, he came across a finely dissected bunch of leaves, shaped like a broom, growing on part of a European birch tree. This was a “sport,” a horticultural term for a plant that produces a branch that looks very different from the host plant.
Trost knew he was onto something. He was a second-generation nurseryman (Southern Oregon Nursery is now in its fourth generation.) So Dieter propagated the cuttings, now sold as Betula pendula ‘Trost’s Dwarf’ (as well as many other common names).
It’s an amazing plant that has to be seen to really be appreciated. A favorite of bonsai growers, it’s also great for rock gardens, which are increasingly popular amid these drought seasons and climate changes. It takes most of a decade for the tan bark to turn into the classic white birch. It is as wide as it is tall, growing 3- to 4-feet high and 3-feet around, so is great for topiaries, as well.
The Trost birch displays some interesting tricks that befit such a wonderful sport. For example, when you first see it, you might think it is a Japanese maple, albeit a beautiful one. It’s only by looking closely, under the leaves, that you will realize that it is, in fact, a birch.
Another fascinating aspect is the peculiar nature of the leaves. They grow to about four centimeters long and three centimeters wide. The doubly serrated leaves adorn the plant like a lace.
But perhaps the most interesting thing is that due to its extraordinary light-green pigment, the leaves can look semi-transparent, gossamer, and pellucid under natural sunlight ... that is, the leaves allow light to pass through but not detailed shapes, so another trick, this one of the eye.
“It was a wonderful discovery,” enthuses Baldassare Mineo, former owner of Siskiyou Rare Plant Nursery, which has now “sported” itself into the Italio Gardens, at 2825 Cummings Lane, in Medford.
“It’s just a sensational introduction.” Mineo says. “To see it is to want it. ... “It’s an elegant habit that rivals and imitates the finest leaf forms from Japan.”
Another bonus is that despite its filigreed, delicate appearance, it is deer resistant and drought tolerant. It is also more hardy against insects, such as borers, than many other birches.
Dieter Trost Jr., one of Trost’s two sons, recently provided a tour of the nursery to show off the eponymous plants — he had two of them in stock. He speculates that the sport appeared due to pollen dropped by a bee or a bird, but he really doesn’t know for sure, adding to the mystery.
The birch was entered into the U.S. National Arboretum in 1984, and is beloved by garden enthusiasts, which is great for Southern Oregon, which has a rich collection of gardeners who appreciate the Trost birch. It’s available online and at Southern Oregon Nursery. Trost Jr. says they regularly sell about 15 of the dwarf trees a year.
“It can be a difficult plant due to the roots,” Trost Jr. says. He explains that birches are naturally drawn to water, but this particular hybrid needs proper drainage because over watering “causes root rot.”
Dieter Trost passed away at home in November 2020 at age 84. His parents established Southern Oregon Nursery in 1945, and Dieter became co-owner in 1955 and owner in 1963, and the business is still family owned and operated today.
He was survived by his wife, Judy, his sons, Dennis Trost (Carie) and Dieter Trost, Jr. (Tammi); six grandchildren and one great-grandchild, Andrew (Kori), Alexa, (son, John), Callen, Ben, Emma and Matt.
Besides seeing the trees at the Southern Oregon Nursery and the Italio Gardens and Nursery, a variety of Begula Pendula (v. lacianata) grows at Post 73 on the self-guided tour in Lithia Park.
The Lithia Park Trail Guide features colorful maps, over 100 photographs and a self-guided tour. The tour begins at the entrance to the park, and is a great way to stroll at your leisure and experience the plants the park has to offer. You can download and print a copy of the guide at www.ashland.or.us/Files/LithiaParkGuide_Digital.pdf
Jefferson Reeder is a freelance writer in Medford. He can be reached at firstname.lastname@example.org.