Winter brings into sharp focus the elegant structure of our native deciduous trees. This pause in the growing season gives us pause to appreciate the unique growth habit and character of the leafy trees that cool us in summer. A winter ramble through world-renowned arboretums is the perfect opportunity to see and appreciate the growth habit and architecture of noble trees. Their canopies may be battered or made asymmetrical by long ago storms, but each is generally recognizable from afar by those who take the time to walk and look and learn.
Boston is world-famous for its museums and cultural sites such as the Museum of Fine Arts, the Isabella Stewart Gardener Museum, Harvard University museums and others. Among them are two living museums that should be on the itinerary of all who love trees and green spaces.
The Arnold Arboretum of Harvard University and Mount Auburn Cemetery are top destinations for tree tourists like me. Fair warning, two afternoons, and a mere four hours to explore each of these greenspace gems wasn’t nearly enough time to do these grand arboretums justice! Already plotting a return in summer to leafy paradise, I share with you some of the bare-branched beauties encountered. Each of these North American native species is currently available for planting today – in anticipation of growing noble trees like these in just 50 or 100 or 200 years. Future generations will thank you!
By Nancy Buley, who is always Thankful for Trees
White Oak
Quercus alba
This venerable giant was a mature tree when Mount Auburn Cemetery was founded in 1831, according to President and CEO Matthew Stephens who took time out of his busy schedule to show me some of the arboreal highlights of the historic cemetery and arboretum. (It was great to reconnect with Matthew, who worked with our nursery during the years he led the MillionTreesNYC campaign.)
White Oaks are among the mightiest of noble oaks. A broad-spreading, storm-resistant shade tree at maturity, its commanding stature in autumn is complemented by red to reddish purple fall colors. Reputed to be slow-growing, well-grown nursery trees grow fairly quickly in 30 years to a height and spread of 45’ x 45’. Unlike English Oak, this North American native oak is resistant to powdery mildew.
Crimean Linden
Tilia x euchlora
Crimean Linden glows glossy green in summer, when its extra-shiny leaves put on a bright show. Said to be more resistant to the feeding of aphids, it’s a popular street tree in Europe as well as in North America. Broadly pyramidal in form, it offers a show of fragrant yellow flowers in late June that is very attractive to pollinators. According to The Tree Book, it is a hybrid of T. cordata and T. dasystyla, a species native from Crimea to Iran. This beauty stands at the top of a hill at a fork in one of the many winding lanes that guide visitors through this National Historic Landmark. Founded in 1831 by members of the Massachusetts Horticultural Society, it was America’s first large-scale designed landscape that was open to the public, and inspiration for the rural cemetery movement of the nineteenth century.
Red Oak
Quercus rubra
Tolerant of urban air pollution and resistant to Verticillium wilt, this fast-growing, broad headed tree performs well under varied growing conditions. it is a valuable oak for lawns, parks, golf courses, commercial areas, boulevards and other landscapes where a fast-maturing, durable and long-lived shade tree is needed. Red Oak is called “the ‘king’ of the northern oak species” by Guy Sternberg and Jim Wilson in their classic Landscaping with Native Trees. Its rich, dark green leaves turn to a dark red in the fall. Maturing to a height of about 50 feet and spread of 45 feet, it is hardy to USDA Zone 4. This handsome tree towers above a roadway that winds through The Arnold Arboretum.
Pin Oak
Quercus palustris
Pin Oak is a tree with a very distinctive growth habit that changes over time. In youth, the strong central leader is maintained to the top. Branches are long, slender and horizontally layered, giving this large tree an elegant, formal, pyramidal appearance in youth that gradually becomes more rounded as it reaches a height and spread of approximately 55’ x 40’ after 30 years in the landscape. Over time, it becomes more rounded and may reach 80’ or higher, as may be the case with this venerable tree growing at The Arnold Arboretum. Summer foliage is deep green and turns rusty orange to red in the fall.
Sunburst® Honeylocust
Gleditsia triacanthos ‘Suncole’
Loved for its golden yellow foliage, this eye-catching cultivar brightens grey days of springtime like a burst of sunlight when leaflets emerge bright yellow. New growth darkens gradually as it matures, creating a two-tone effect as yellow leaf tips continue to emerge throughout the growing season. A somewhat irregular branching habit leads this cultivar to develop a loosely rectangular outline at maturity. Its light, airy shade is welcome in cities striving to increase shade canopy cover and welcomed by visitors to the gravesites cooled in summer by its long shadow.
According to a copper plate hung at eye level, this handsome specimen was planted in 1972, 20 years after its introduction by Cole Nurseries of Ohio in 1952.
Bald Cypress
Taxodium distichum
The soft and feathery foliage of Bald Cypress belies the tough character of this deciduous conifer. Its flat, short needlelike leaves are borne in graceful sprays that emerge a pale green in the spring and darken to medium green through the summer. Foliage turns to rich orange-bronze in the fall prior to leaf drop. Winter stems glow golden orange, adding color and texture to the season. Although it thrives in swampy or waterside conditions, it is also remarkably drought and heat tolerant, and is proving to be a widely adaptable city tree.
It was a special treat to spot a Blue Heron doing its best to blend in with the cypress “knees” growing at the base of this lakeside grove at Mount Auburn Cemetery.
