Can I Plant a Palm Tree in Portland?

Sometimes we get called to a house where the homeowner is afraid for an ailing tree, then when we show up, guess what? They want to know if they can plant a palm tree as a replacement tree in Oregon and wonder how to keep it alive. People in Portland, listen up – unless you are a horticulturist or arborist, don’t attempt to plant a palm tree in your yard! It will not ever be like the palm trees in sunny California, the main reason? This is NOT “sunny” California. So what can you plant? Here’s how to know – it’s something called hardiness zones.

What are Plant Hardiness Zones?

Plant Hardiness Zone Maps were created by the USDA (United States Department of Agriculture) to help all growers determine what plants will flourish in their area. Here is what the full map of the United States looks like.

USDA hardiness zones for planting trees

Technically speaking, the map maps out zones based on average temperatures for the area. All landscaping zones are divided by 10 degrees Fahrenheit. The zones are based on average temperatures over the past 30 years and do not reflect the coldest temperatures ever recorded or account for the coldest possible temperature in the future. It is important for growers to consider this when choosing plants or trees, like palm trees that are not rated specifically for their landscaping zone. If you are new to gardening, we always recommend staying with plants  and trees recommended for your landscapezone. Here’s what the map for our state of Oregon looks like. For those of us situated around the Portland area, we fall within the 8B landscape zone, or plant hardiness zone.

Oregon hardiness zone map

What are Microclimates?

Microclimates are smaller areas that have fine-scale climate variations. For example, microclimates may appear around blacktop, concrete, or small hills that can cause cool spots in your yard. Every yard or landscape is different, and it is important to note any microclimates you may have on your property. Likewise, it is possible that your entire yard could be part of a microclimate. This happens most often when a yard is very sheltered or very exposed. There are a few other factors that can change a gardener’s idea of what they should or should not plant.

Other Factors to Consider When Choosing Plants or Trees

  • Light – It is important for plants and trees to receive the ideal amount of sun. The amount of sun an area in your yard receives can vary greatly between summer and winter depending on your area and the amount of shade. Consider what temperature variances can happen in both the summer and winter in accordance with the possible amount of sun before choosing to plant something on the fringe of your hardiness zone.
  • Soil moisture – This is usually not a problem in Oregon, but occasionally soil with too little moisture can affect how well a plant or tree does in a particular zone.
  • Temperature – Look for the optimal temperature range for a specific plant. While some plants can handle varying temperatures, others cannot. Before you plant, know what temperatures a specific plant or tree can handle.
  • Humidity – High relative humidity limits cold damage by limiting moisture loss from sensitive parts of the plant (leaves, branches, and buds). Cold injury can be more severe if the humidity is low, especially for popular in Oregon, evergreens.

So Palm Trees are a Bad Idea, What Can I Plant?

Don’t think keeping it to your hardiness zone means you are limited in choices. The Portland, Oregon area is known for supporting a vast array of trees and plants. Some tree ideas? Maple, Japanese Maple, Hazelnut, Oak, Cherry, and loads of pine trees. If you need help selecting trees for your yard, read our previous post, Choose the Right Tree – Tips from a Certified Arborist, or give us a call! We are happy to help customers learn about trees, and hope to hear from you soon.

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