A look at some uncommon flowering trees

The spring season of 2017 featured the most beautiful display of flowering trees and shrubs that I can recall in my life. Of course, my long-term memory is not what it used to be, but almost every horticulturist I have spoken with this year agrees.

There is a bit of a letdown as we officially enter summer and the number of varieties of flowering trees and shrubs diminishes. One of the perks of living in this wonderful region is to be able to drive through two or even three hardiness zones in less than an hour. You can drive from the village of Rhinebeck (elevation 200 feet), which is probably in U.S. Department of Agriculture hardiness Zone 6B, to Hunter Mountain Fire Tower (at over 4,000 feet), probably in the department’s hardiness Zone 4B, to essentially go back two or three weeks in time and enjoy many of the same trees and shrubs in bloom for a second look.

Of course, there are plants in Rhinebeck that will not grow on Hunter Mountain due to hardiness, but both regions share many of the same species. This reminds me a bit of the mountains of western North Carolina, where it seems like they enjoy all the plants we have here, but also have lots more!

In the past 20 or 30 years that I have paid attention to these things, I have noticed a distinct increase in the number of tree species that can tolerate our winters. Global warming proponents like to point out these trends as evidence of climate change, but 20 or 50 years even is an eye blink in the big picture of our planet.

The winter of 2014-15 was one of the coldest on record and I noticed that many of the borderline hardy plants either perished outright or failed to bloom at all. Still, there are some interesting trees and shrubs that you might want to try growing today that I would not have recommended years ago.

The golden rain tree (Koelreuteria paniculata) is reported to be hardy from the U.S. Department of Agriculture’s hardiness Zones 6 to 9, but my friend Lester, who lives at an elevation of over 1,200 hundred feet in the town of Durham (Zone 5), has successfully grown this species for many years. It is a relatively small tree, topping out at about 20 feet tall that features 12- to 15inch long, hanging clusters of bright yellow flowers in June and nice yellow fall color as well. It is highly tolerant of poor soils and clay soils and will grow almost anywhere, as long as it has full sun. It can also tolerate urban conditions, drought and air pollution.

Lester also grows the Golden Chain tree, Laburnum anagyrodies, which features 10-inch-long hanging clusters of bright yellow flowers, similar to Wisteria, (but yellow) in May or early June. It is also a small tree, growing to 25 feet tall and 15 feet wide. It can tolerate partial shade and poor soil as long as it is well-drained, but it prefers alkaline soil and will benefit from lime applications (like lilac). It does need to be trained to a central leader when young.

All three of these trees are well-suited for growing under power lines due to their relatively short stature.

Fringe trees, Chionanthus virginicus, are actually native to the Southeastern United States, but there is a very similar cultivar called the Chinese fringe tree, C. retusus. These small, 10- to 15-foot trees may be covered with spectacular snow white flowers in late spring/early summer. The delicate blossoms will last longer if the tree is protected from wind, but it flowers best in full sun. It likes welldrained fertile soil, but Lester’s soil is heavy clay and not particularly fertile.

All three of these trees are well-suited for growing under power lines due to their relatively short stature. All are available at local garden centers as well.

Next week, I will continue this topic and will include some unusual shrubs.