EDDIE SEAGLE: The amazing river birch

“Did you know that a bee dies after he stings you? And that there’s a star called Aldebaran? And that around the tenth of August, any year, you can look up in the sky at night and see dozens and dozens of shooting stars?”

— Elizabeth Enright, “Then There Were Five”

Saying goodbye to July and welcoming August as the days continue to shorten and we start thinking about the closure of summer and the beginning of fall activities. In the landscape, we consider what plants to install and how they will improve curb appeal and satisfy our own personal needs.

The amazing river birch (Betula nigra or water birch) is such a tree — a species of birch native to the eastern and southern United States. It is a deciduous tree commonly found in the flood plains and swamp areas. The bark of the river birch is usually dark gray-brown to pinkish-brown and scaly. And, in some situations, it appears smooth and creamy pinkish-white with exfoliating, curly, papery sheets. The flowers are wind-pollinated catkins with the male as pendulous and the female as erect. The fruit matures in the late spring and consists of numerous tiny, winged seeds positioned between the catkin bracts.

While its native habitat is a wet, lower environment, the river birch will grow on higher elevations. Its bark is very distinctive, thus making it a favored ornamental tree for landscape uses. Several cultivars with whiter bark than the typical native type have been selected for landscape planting, including Heritage and Duraheat. Also, these two are recognized as being tolerant of the bronze birch borer (Agrilus anxius) in warmer areas of the southeast.

The cinnamon-colored, exfoliating bark of the river birch is awesome in appearance during the winter months (fall leaf color is golden yellow). During the growing season it exhibits lustrous, medium-green leaves (silvery white underneath) and tolerates wet soils and dry summers. It does not tolerate shade and prefers slightly acidic to neutral and moist soil conditions. The river birch is the most common birch tree found in our area since most birch species prefer the cooler climates to the north. It is a fast-growing tree, but its life is short compared to most trees.

The bark of the river birch varies according to its age, as young trees have a silvery gray bark with light reddish-brown patches and the older trees have dark reddish-brown bark (almost black). It has two different flowers with the male flowers growing in the fall, remaining on the tree through the winter, and producing pollen in the early spring. The female flowers grow in the spring and turn into fruit (cones filled with hairy seeds) in May and June after pollination and are dispersed by wind and water. The ripening of seeds coincides with high water levels of rivers (its native setting), thus allowing the seeds to be carried long distances by the water. The seeds germinates quickly in the mud, allowing them to grow in areas where they help prevent erosion.

In such natural settings, the river birch usually grows close to water and is often found on sandbars, islands in streams, streambanks, lakeshores and floodplains. Other trees found growing in nature in the vicinity of the river birch include American sycamore, red maple, silver maple, black willow, American hornbeam, yellow poplar, blackgum, black cherry, American elm, sugar maple, boxelder, mockernut hickory, American beech, ash, sweetgum and pin oak.

The river birch is one of the most recognizable and beautiful trees in the landscape. It sheds its bark constantly, which drops underneath the tree as a beneficial mulch that prevents aggressive competition from weeds and other unwanted plants. It is much more resilient and heat tolerant than the white paper birch and is very popular for landscaping on estates, golf courses, metropolitan locations, small business locations, recreational areas, parks and homes. The river birch is also a very popular lawn tree that thrives easily in hot, humid locations and exhibits the attractive peeling bark feature. As one of the fastest growing and outstanding shade trees, it can offer energy savings through temperature control and lower your electricity bill as an added bonus.

The river birch can be purchased as a multi-trunk shade tree, although the single trunk specimens are most preferred. It can be used as a screen or shade tree and as a street tree with irrigation. They are attractive when planted in groupings, especially against a dark background. Because of its shallow root system, the river birch is easy to transplant. It should be pruned during the summer to minimize the excessive sap bleeding which can result from spring pruning.

The cultivars include Cully (a broad pyramidal with lighter bark than the species and large, glossy green leaves offering a good resistance to bronze birch borer) and Heritage (a heat-tolerant, highly adaptive cultivar with larger, glossier leaves). The Royal Horticultural Society labels Cully as Heritage and is sold under the name of Heritage even though many distinguish it as an independent cultivar.

Heritage received a Pennsylvania Horticulture Society Gold Medal in 1990 and was selected as 2002 Tree of the Year by the Society of Municipal Arborists. The bark of Heritage is whiter than any birch resistant to bronze birch borer. Heritage offers many positive traits including a cold tolerance in northern environments and a tolerance of the heat of the southern environments.

Other cultivars include Duraheat (glossy dark green, closely spaced leaves with yellow fall color, aphid resistant, and bark exfoliation at early age), Fox Valley (a dense, compact, oval to rounded habit with branches to the ground and dense foliage), and Suwanee (lustrous dark green leaves with salmon-white exfoliating bark). Avoid those selections that exhibit growth patterns not consistent with the species, including variegated leaves and weeping growth habits.

May the results of your immediate efforts be long-lasting so that you can enjoy the fruits of your labor for seasons to come. Think sustainability. Keep your hanging baskets and potted plants refreshed with water and food. Remember to feed and water the songbirds, and give your pets the care they need (do not leave them unattended in a hot car or tied to a tree all day long). Also, be on lookout for children along the streets and roadways throughout our communities as the summer gives way to the start of a new school year. Let’s keep everyone safe.

“The Lord does not look at the things man looks at. Man looks at the outward appearance, but the Lord looks at the heart.” 1 Samuel 16:7.

Eddie Seagle is a sustainability associate, Golf Environment Organization (Scotland); agronomist and horticulturalist, CSI: Seagle (Consulting Services International); professor emeritus and honorary alumnus, Abraham Baldwin Agricultural College, and associate editor of The Golf Course, International Journal of Golf Science. Direct inquiries to [email protected].