Trees to Plant this Spring

Morris Arboretum just published a new blog post called, Thinking Ahead of Climate Change. Reading their blog post reminded me of a lecture I attended at Morris in December. The lecture, titled “Woody Plant Diseases and Pests in Our Changing Landscape” began with an overview of climate trends in the mid-Atlantic region.

In 1990, the greater Philadelphia region was classified as Zone 6 by the USDA.

By 2006, our region had moved to Zone 7 on the Hardiness map.

According to future hardiness indicators, we will be Zone 8 by 2039 and Zone 9 by 2070.

Hardiness Zone is one of the key pieces of information we look for on a plant label when determining if a plant will thrive in our landscape. As we make new selections, particularly for tree plantings that we hope will survive for decades, if not centuries, to come, we must consider their preferences and adaptability. In that regard, we must consider periods of drought, extreme precipitation events such as flash flooding, and extreme high and low temperature swings. Remember on December 23, 2022, our region experienced a remarkable 51° temperature swing from a daytime high of 57°F to a nighttime low of 6°F.

Fortunately, entomologists, plant pathologists, arborists and nursery owners have closely monitored these environmental changes and have provided us with ample resources to make informed choices when selecting new plants, particularly trees.

One such resource, the Climate Change Response Framework, has a particularly helpful document that projects which specific tree species have good climate change capability vs. which tree species have poor climate change capability. This is definitely a document that I would reference when deciding about which tree species to plant in our region. Click here to access the PDF. Alex and I are very happy to see our favorite tree, the White Oak, has good adaptability and will likely continue to do well in this region.

Another fantastic document that I have enjoyed interacting with is provided online by J. Frank Schmidt & Son Co., an Oregon-based wholesale nursery that recently celebrated 75 years in business. Their PDF, Urban Tree Selection for a Changing Environment, was published in 2017 and includes a list (with links!) to 35 “climate resilient” tree species. A few that particularly stood out to me are: Native Flame American Hornbeam, Royal Raindrops Crabapple, Afterburner Tupelo, Crimson Spire Oak, Cobblestone Oak (interesting bark), Streetspire Oak, Skinny Genes Oak (for tight spaces or smaller landscapes), Shawnee Brave Bald Cypress (it will grow in standing water!), and Emerald Sunshine Elm.

While thinking about climate change can be a bit depressing, there are two things to remember:

1. Trees are extremely resistant, resilient and adaptable. Despite drought, raising air temperatures, and extreme flooding events, it is still easy to have trees that will thrive in your landscape so long as they are given routine care and maintenance. For example, an annual deep root feeding of nutrients mixed with Hydretain Soil Moisture Manager, will help any tree with water retention in the dry months of July and August. We recommend this service for anyone with a particularly significant tree or shrub on their property.

2. As demonstrated by the list of trees from J. Frank Schmidt & Son Co. above and the Morris Arboretum blog post, industry experts are working to hybridize tree species that are resilient against insect and disease pressure, heat and drought, and even standing water. It is important to make informed decisions about the trees and shrubs we select for our landscape and to always choose the right tree for the right place.

If you need help selecting the right tree to plant this spring, please reach out! We are always happy to share our recommendations!