Trees are the cornerstone of a lot’s landscape, often its largest and most expensive accents.
When considering which trees to add to your oasis, your first step should always be to consult a local arborist. Arborists are invaluable resources; experts in the types of trees that thrive in your area, the maintenance they require, and the threats they may pose. An arborist can help you evaluate your landscape picks based on region, look, and function.
Research your Hardiness Zone to learn which trees can grow within the extreme temperature ranges of your area. The 11 zones are determined by the typical high and low temperatures of each region. Altitude, latitude, and type of climate are all factors that determine which trees can survive in each region.
As hardening drought continues to threaten many regions of the U.S., greenscaping is becoming increasingly important when choosing the trees, shrubs, and flowers to include in your landscape. While foregoing lush lawns is the cornerstone of the movement, thirsty trees may be culprits worthy of the same guilt. It’s important to only plant trees that are well-suited to your environment and will thrive with the amount of water and sunlight typical to your region. Trees with large dark, glossy leaves tend to absorb more heat and consume more water as a result. Soft, pithy, fleshy trunks are a good indication of water-needy trees, too. Unless you live in the tropics, opt for trees with leaves that are lighter or silvery in color, or leaves that are hairy. They naturally diffuse light and retain water, so they need less.
Determining which trees suit your desired upkeep can feel a bit like choosing a pet. You’ll have to consider: Does it shed? How often does it need to be fed? Does it require grooming? Contemplate whether you want your landscape to flex your green thumb or be the poster child for self-sustainment. Some trees may require the work of an arborist to keep healthy or visually attractive, with annual tree pruning and tree shaping. Choosing trees suitable for your climate—especially in drier climates—means you’ll spend less time watering.
Take into account whether a tree is deciduous or coniferous. Deciduous trees drop all of their leaves in autumn while coniferous trees may drop some of their needles throughout the year. The dropped leaves of deciduous trees actually make great compost and can return nutrients to your vegetable garden’s soil. Some pine needles increase the acidity of soil when dropped, meaning grass around the trunk of some coniferous trees will die. If a coniferous tree species is deemed fit for your climate, consider planting it in a slight mound of mulch-covered soil. The mulch will stay visually appealing where grass may otherwise have turned to bare soil. Mulch also offers the bonus benefit of helping soil retain moisture.
Size & Form
How long will your tree take to reach its mature size? Trees that grow slowly typically live longer, but they may take longer than you’d like to provide shade to nearby shrubs or produce succulent fruit. Also consider the proximity of your tree to your house or other structures in your yard. Know how big each tree is expected to get and use that to determine how far trees should be planted from structures and each other. Pruning can prevent complete tree removal by trimming branches that cause a tree to tilt to one side, obstruct power lines, are diseased, or are too close to a structure. Note that creating too much shade over a structure can cause rotting.
Shape determines how a tree fits into the space at large and how well it will achieve your goals. Tall trees with large canopies are ideal for creating shade while some species, commonly shrubs, need shade to survive. Trees that grow in columns, like Poplar, work well in landscapes where space is limited.
Climate-suited trees that produce fruit can be a fun landscape addition with the added benefit of providing fresh food steps from your kitchen. Planting for your climate is even more important when considering fruit trees. Kumquat and apricot trees are drought-resistant while banana trees are 90% water. Some fruit trees require two trees (male and female) to bare fruit and therefore aren’t ideal for small spaces.
Trees are also a great way to draw wildlife to your yard (plus, making space for wildlife is a rule of greenscaping!). Research common native animal species in your area and what they prefer in both food and habitat. Linden, Willow, and Franklin trees are all good sources of bee food, supporting the pollinating insects that are crucial to the health of your entire yard. Keep in mind that trees that drop berries may be annoying to have near a sidewalk where they can stain cement. Rethink planting a tree that drops poisonous berries especially if you have small children who may consume the toxins.
Prohibited & Invasive Species
Nearly every country struggles with an epidemic of non-native species and the U.S. is no exception. Though nuisance and invasive species are known to harm ecosystems, they remain a prevalent choice for landscaping. Nuisance species are non-native trees that threaten health and safety. They may overtake natural habitat or be toxic to humans or soil. Nuisance species should definitely be avoided but are not as threatening as invasive species that prove to be detrimental to native ecosystems. Invasive species spread at an inflated rate, overtaking native ecosystems and posing threat to human health, the environment, and the economy. Invasive species displace native vegetation and threaten biodiversity.
Check your city’s website for information concerning banned (or celebrated) trees in your area. The city of Portland’s Portland Plant List is a great example of an extensive resource that lists native plant species including trees, shrubs, flowers, and weeds, as well as which species are considered nuisance or invasive. The Portland Plant List even identifies common plants that are considered beneficial to its residents and ecosystems, as well as species the city is working to eradicate.