The Green Oasis: Broad Leaf Trees in Portland

Are you tired of the dreary winter landscapes dominated by leafless trees? Portland’s urban forest could be a lot greener even in the winter with the addition of more evergreen trees. While our city boasts a mild climate, a heavy reliance on deciduous trees has left our streets and parks looking barren during the colder months. Let’s explore some exciting new options for broad leaf evergreen trees that can bring life and vibrancy to our city all year round.

A Sweet New Magnolia

Urban Forestry has recently introduced a second American magnolia to their list of evergreen choices: the northern sweetbay Magnolia virginiana ‘Jim Wilson.’ This unique cultivar, trademarked as Moonglow, offers a more evergreen characteristic compared to other sweetbays from the northern region. With its upright growth reaching up to 35 feet, it can quickly become a focal point in any landscape. The silvery white leaves and lemon-scented, cream-colored flowers add a touch of elegance to the tree, while the glossy red seeds attract birds. Although it may not provide as deep a shade as the southern magnolia, it still offers a beautiful addition to any garden.

A Southern Belle That Endures Northern Winters

Magnolia grandiflora, the official state flower of Mississippi, has stood the test of time and has made itself at home even in the northern regions. Originally from Florida, the M. grandiflora ‘Edith Bogue’ has proven to be hardy enough to survive Portland’s cold winters and snowstorms better than other cultivars. This evergreen tree with its large, white lemon-scented flowers has been a favorite for centuries and remains popular worldwide as a park, garden, and street tree.

Bambooleaf Oak: A Street Tree Beauty

Among the oak family, one of the most attractive street trees is Quercus myrsinifolia, also known as the bambooleaf oak. Native to China, Korea, and Japan, this oak has proven its hardiness in Portland’s climate. With its rapidly growing height of 30-35 feet, it forms a round-headed tree with smooth gray bark. The new leaves emerge in an attractive silvery purplish red color, adding a unique touch to the landscape. This oak has already withstood ice storms and snowfalls, proving its durability in harsh weather conditions.

Silverleaf Oak: A Drought-Tolerant Beauty

From the southwestern United States and northern Mexico comes the silverleaf oak, Quercus hypoleucoides. This tree is named for its silvery undersides of the leaves, giving it a distinctive look. It is known for its fast growth, forming a densely branched tree that can reach 40 feet or more in a short period of time. The leathery gray-green leaves make the tree incredibly drought tolerant once established. Whether it’s cold or hot, the silverleaf oak can handle it all, making it a great choice for Portland landscapes.

Oregon’s Own Broadleaved Evergreens

While many Portlanders are familiar with the native madrone Arbutus menziesii, there are other broadleaved evergreens that call Oregon home. Canyon live oak (Quercus chrysolepis) and Oregon myrtle (Umbellularia californica) are two examples of trees that thrive in our region. Canyon live oak, which can grow up to 80 feet tall, is a stately tree with leaves resembling holly. Native Americans used the acorns of this tree for various purposes. On the other hand, Oregon myrtle, also known as California bay, is a shade tree that reaches heights of 60 to 90 feet. Its heavily spicy leaves have earned it the nickname “headache tree.” Both trees add unique characteristics to the local flora.

Welcome Californians: Interior Live Oak and Blue Oak

California’s native trees can also thrive in Portland’s climate. Interior live oak (Quercus wislizeni) is a drought and heat-tolerant tree that can survive on minimal rainfall. With its broad and densely branched structure, this oak provides shelter and food for many birds and animals. Blue oak (Quercus douglasii), named for its powder blue or blue-green leaves, can defoliate in colder winters but quickly regenerates in the spring. Native Americans had multiple uses for blue oak, making it an important part of their culture.

Southern Live Oaks: A Symbol of Endurance

Quercus virginiana, or Southern live oak, is a long-lived tree that can withstand the test of time. Surviving even the Civil War, these trees can reach heights of 60 feet or more, casting their shade during hot summer days. With dark green leathery leaves, these oaks are a beautiful addition to any landscape. While they may drop their leaves in colder winters, they quickly regrow in the spring, showcasing their resilience.

The Noble Laurel: A Mediterranean Treasure

If you’ve ever spiced up your pasta with bay leaves, you’re already familiar with the true bay laurel, Laurus nobilis. This evergreen tree, native to the Mediterranean, has aromatic leaves that have been used for centuries for their culinary and decorative purposes. With its dense foliage, the bay laurel can reach heights of 30 feet or more. The small yellowish flowers followed by shiny black fruits are a favorite among birds.

A Long-Lived African and European Tree

Holly oak (Quercus ilex), also known as holm oak, is a special tree that hails from the mountains of Algeria, Morocco, and the Iberian Peninsula. Its leaves, reminiscent of holly in their spikiness, turn pale white underneath. With a dark brown to almost black bark, this tree can reach heights of 60 to 80 feet. In its native habitats, holly oak is home to endangered primates and has been a part of cultural traditions for centuries. However, caution should be exercised when planting this tree near natural areas to prevent invasive spread.

Why Do Evergreen Trees Matter?

In a city where winter can be emotionally and environmentally challenging, evergreen trees play a crucial role. While deciduous trees dominate other northern cities, Portland has the advantage of a mild climate that allows for a greater variety of evergreen tree options. The addition of evergreen trees not only brings color and life to our city’s landscapes but also helps intercept moisture and prevent flooding, especially during the rainy autumn months.

To encourage change, Urban Forestry has expanded its Approved Street Tree Planting Lists to include more evergreen choices. Among these options are twelve broadleaved evergreen trees, including the beloved Magnolia grandiflora ‘Edith Bogue’ and other exciting newcomers.

Let’s embrace the beauty and benefits of evergreen trees and transform Portland into a green oasis that thrives year-round. To learn more about broad leaf trees and their impact, visit Ames Farm Center.