Drought-Tolerant Trees for the Pacific Northwest

Drought-Tolerant Trees for the Pacific Northwest

The Pacific Northwest is known for its wet winters and dry summers, making it hard to find trees that are good in drought. But there are plenty of drought-tolerant trees that are native to the region, as well as some non-native varieties that can thrive in our climate.

Unfortunately, the prolonged drought we are beginning to experience could have long-term and potentially devastating effects on our forests. A single season of drought-induced stress may not be enough to kill a tree, but repeated exposures can be fatal. Newly planted trees are particularly vulnerable to these conditions, and weakened trees are more likely to succumb to disease or insect infestations.

According to some climate projections, annual average global temperatures could rise between 1.5 and 7 degrees Celsius (2.7 to 12.6 degrees Fahrenheit). The winters are expected to be wetter and summers to be dryer.

The Pacific Northwest is home to some of the most diverse coniferous trees in the world. Their deep root systems are better able to reach moisture in the ground, making them more resistant to drought conditions. Their ability to withstand cold temperatures and high winds makes them ideal for the region’s climate.

Here are just a few of the drought-tolerant trees that do well in the Pacific Northwest Landscape:

  • Maidenhair Tree (Ginkgo biloba) – The Ginkgo tree has beautiful fan-shaped green to yellow leaves. It is a popular fall specimen tree and grows 25-50 ft. tall and 25-35 ft. wide.
  • Golden Rain Tree (Koelreuteria paniculata) – This is a small deciduous tree with a rounded canopy and bright yellow flowers in summer. It can grow 30 to 40 feet tall high and equally as wide.
  • Dwarf Strawberry Tree (Arbutus unedo ‘Compacta’) – This popular tree has reddish peeling bark and pinkish-red fruits similar to strawberries. This tree is a slower grower, about 8-10’ tall and wide at maturity.
  • Western Redbud (Cercis occidentalis) – his native plant has bright pink flowers in spring and green, heart-shaped leaves. It grows to about 10-18’ tall and wide.
  • Incense Cedar (Calocedrus decurrens) – This popular evergreen is a dense conifer that grows 70-90’ tall and 50’ wide.
  • Bur Oak (Quercus macrocarpa) – This hardy oak can grow to a height of 70–80′ and a spread of around 80′ at maturity. It has textured bark and large acorns for wildlife.
  • Eastern Red Cedar (Juniperus virginiana) – This heat-tolerant evergreen can grow to a height of 40–50′ and a spread of 8–20′ at maturity.
  • White Fir (Abies concolor) – This fairly slow-growing fir tree can grow to a height of 30–50′ and a spread of about 20′ at maturity. It is also not bothered by pests.
  • Japanese Zelkova (Zelkova serrata) –  This medium to large deciduous tree typically grows to 50-80′ tall and is often used as a street tree or shade tree.

You can plant drought-tolerant trees with other drought-tolerant plants in the garden. Drought-tolerant trees still need nurturing for the first three years. They’ll be less stressed if planted in late winter or early spring. Don’t forget to water your trees while they’re getting established. Continue to water them even after established.

If you need help with tree planting or other tree care services, call us at 360-574-4125.

Watering Your Trees in Summer

We often water our plants and lawn but forget that trees need water too! Watering trees may be necessary during summer’s hot, dry weather, especially if your trees are young or newly planted.

Trees need an average of one inch of water per week. When watering trees, deeper, less frequent water applications promote better root growth than shallow, more-frequent irrigation.

Young trees haven’t yet grown an extensive network of roots. That’s why they can’t store much water and need water more often. Young trees should be watered once or twice a week in dry weather. Approximately 20 gallons of water per week are recommended.

In times of drought, when it hasn’t rained for a month or more, even large, mature trees will need watering. You can plan to water mature trees 2 – 3 times a month if they are well established.

The best way to water trees is to slowly water them for a long time in the morning or evening so the roots have time to absorb the moisture from the soil as it soaks down. The roots that absorb the water aren’t deep. Roots spread out sideways; most are just a foot beneath the soil’s surface. On a mature tree, roots extend far in all directions, so focus on watering the area beneath the branches.

Effects of High Temperatures on Trees

Prolonged heat and improper summer irrigation can cause permanent damage to your trees, creating potential hazards that pose a risk to your home and property.

Don’t wait until it’s too late to observe your tree’s signs of drought stress. Often insects and pathogens will attack trees that are already weak. Proper deep root watering is the best way to establish your tree’s root system for long-term plant health.

There are some signals to help you spot signs of early stress. If your tree’s leaves are dying off, wilting, or showing folded or crispy leaves, those are signs of a problem. You may still be able to take measures to restore the overall health of your tree.

Other Signs of Irrigation Stress Include:

  • Leaf wilting, curling, or folding
  • Leaf scorch
  • Needle drop in conifers
  • Canopy die-off of main branches or new growth
  • Insect or disease Issues
  • Premature fall color on leaves
  • Leaning or wilting new branches

Watering too much or too little can be harmful. Don’t overdo your watering, as it could cause insect or disease issues.

Let us know if we can help take care of your trees this summer. Give us a call at 360-574-4125.

Winter Pruning

Winter Pruning

As we’re looking forward to Spring, and hoping it’s around the corner soon, late winter is a good time to do some pruning, particularly on deciduous trees and shrubs. In Winter we can view the overall structure of a tree or shrub, without it being obscured by leaves. It’s also healthier for the tree to be pruned while dormant, before the sap begins to flow in Spring. Pruning in the summer will take away some of the plant’s energy (in leaves), this is stored safely in the roots in the winter.

Prune trees and shrubs that bloom on new wood

First of all, make sure that you’re not pruning a tree or shrub that will be blooming soon, like Forsythia, or Western Redbud (Cercis Occidentalis) or the Star Magnolia (Magnolia stellata), unless there are some dead or diseased branches that need to come out.  Plan on pruning them after they bloom.  Similarly, don’t prune your Rhododendrons now, or you’ll cut off all those beautiful blooms.

Why Prune

Secondly, be clear on why you’re pruning.  Maybe the tree’s size needs to be controlled, or the branches need thinning, so that lower branches, or plants growing beneath can get more light.  Or perhaps there are some structural defects that need to be addressed; dead or diseased branches to remove, or crossing branches growing in the wrong direction.  Regular pruning will help light penetrate the canopy, and air circulate, resulting in a healthier tree.  Over time you will develop an eye for the pruning cuts that should be made.  But be careful of over pruning, you should prune out no more than a quarter of the canopy or even less, it’s best to be conservative on this.  If you are not sure, consult an Arborist, there is great value in a well pruned tree!

Selecting the correct species to prune in Winter

Trees and shrubs you can prune right now tend to bloom in summer; June and beyond.  Crape Myrtles (Lagerstroemia indica), which are late summer bloomers and trees, such as the Katsura tree(Cercidiphyllum japonicum), Smoke tree (Cotinus species), Hornbeams (Carpinus species) and Oaks (Quercus species).  Shrubs such as Buddleia, Abelia, Caryopteris, and Hibiscus can  be pruned now.  Fruit trees, such as Apples and Pears can also be pruned.  Since they are grown for fruit, the reason for pruning is to access fruit, and to develop a strong leader and well-spaced scaffold branches to bear fruit.

These plants will bloom on this year’s growth, so there’s no danger of pruning off blooms.  Often there are spent blooms to trim back, and pruning will also help to control the size of shrubs and trees, encouraging new growth, and keeping them more compact, and less woody.

Some evergreen trees and shrubs, such as Spruce (Picea), Fir (Abies), Yew (Taxus), Holly (Ilex), and Boxwoods (Buxus) can also be pruned in late winter, while dormant. 

As you’re pruning, always keep in mind the habit (the way the plant wants to  grow naturally), and try to accentuate its features, and allow it space to grow.


The International Society of Arboriculture (ISA), has a handy guide on tree pruning for the consumer:



Oxydendrum arboreum

Oxydendrum arboreum

Oxydendrum arboreum – known commonly as sourwood – is one of the great trees for small spaces with a history of healing. The oval-shaped tree grows 20-25 feet tall, provides year round interest and exceptional fall color. It is common in the nursery trade as a large multi-stemmed tree or with a central leader. It requires very little pruning and is tolerant of most soil types.

As the tree matures its bark becomes gray, ridged and scaly, adding to visual interest in the winter months. Pioneers used to chew sourwood bark for mouth pain, draw its sap to relieve fever and brewed leaf tea for digestive maladies. Truely an all season tree for both its look and herbal remedies.

Today sorrel leaf tea is widely used to slake the thirst of mountain climbers. In spring the branches take a back seat to glossy green leaves 5-8 inches long and sour to the taste, hence the tree’s common name.

Summer ushers in drooping 4 to 8-inch clusters of waxy, fragrant white blooms very much like lily-of-the-valley. These are a favorite of pollinators and sourwood honey is a delicacy in Pennsylvania south to Florida and Louisiana. Where the tree is native.

The flowers make their parting bows, making way for unusual fruit that looks like brown, wooden capsules and contain numerous pointy seeds.

Fall is where this tree takes center stage in the landscape, dense leaves take on intensely beautiful shades of brilliant crimson, purplish-red and sometimes yellow.

Winter, spring, summer, fall: Oxydendrum arboreum shines as a lawn specimen, a garden feature, an ornamental addition in a tree line or as a clump in a wide open space.

Preventing Poor Tree Care

Preventing Poor Tree Care

Getting your trees off to the right start 

Summer is a great time to take a look at your trees. It makes it easy to spot dead wood and begin the process of training young trees to develop a healthy and attractive canopy as they grow. Summer pruning should be light and selective. Young trees may benefit from early training to avoid future issues. Summer is NOT the time to aggressively prune your trees. Frontier Tree Care can save you the risk of having your trees damaged or poorly pruned, which can have lasting effects on your home and can lead to ongoing issues. The wrong style or methods of pruning make it challenging, if not impossible, for trees to recover from. We will get it right the first time! Contact us today!

Treating Pest/Disease Issues 

We are committed to maintaining high quality environmental standards that minimize the use of harsh chemicals for pest issues. Your landscape adds value to your home and your plant and tree health is a huge component of a beautiful outdoor space. We are in business to help you find the right solution to promote health, growth, and performance of your trees and landscape plants for years to come. We will work with you to develop a plan to prevent disease and pest issues and provide proper treatment for unavoidable circumstances. 


The optimal time to fertilize trees in the Spring when they break dormancy or in late Fall prior to dormancy. It’s easy to confuse things in the summer if you are actively fertilizing your shrubs, annuals and perennials. Another common garden mistake is trees inadvertently absorbing fertilizer that is meant for lawns that contain herbicides. This can damage them, especially young trees. 

June Landscaping and Pruning

June Tree Landscaping and Pruning

Summer is nearly here and everything is lush and green! It’s the right time to just enjoy the garden, while keeping up on landscaping and pruning maintenance. We have a few tips for you, this June, to keep your landscape healthy and gorgeous.


tree pruningWhile pruning is the most common tree maintenance project, we don’t recommend doing any heavy pruning in summer, as any high temperatures can damage freshly pruned trees & plants. We always want to keep the nature of the tree in mind – incorrect pruning can permanently damage or kill the tree’s life.

However, the start of summer is a good time to do minor pruning of flush growth, to help trees & plants keep their shape during this time of increased growth. This is especially applicable to evergreen conifers, whether they are trees or shrubs. This minor pruning helps maintain overall health, without harming the core of the plant. Our maintenance team can come out to help you with this type of pruning and to spruce up your yard while they’re at it. 

Routine, proper pruning to remove dead, diseased or weak limbs can happen any time of the year without harming the tree. It is necessary for safety, clearance and overall landscape planning.  Get an estimate by clicking here.


As the warm weather starts, now is the perfect time to get your system started on for the year. residential irrigation Vancouver WAAs summer goes on, trees depend on homeowners more and more for water. It’s important to take care of your trees and shrubs with proper watering. 

The amount of water a tree needs depends on a variety of factors – age, species, time of year, weather and soil type. New trees need more watering than older ones, but as it gets warmer, all trees will need extra watering. You’ll need to find the balance between enough water to keep younger trees growing, and older trees healthy. You don’t want your trees & shrubs to be dependent on irrigation – they need to be able to survive on what mother nature provides. 

A good irrigation system can be adjusted, based on rainfall, so you can tailor it to the weather. Start now to get on a regular schedule by the end of June. July, August, and September are generally very dry months. Hopefully, by now you have had your backflow testing and any repairs done – if not contact us soon to get prompt service.


weedingGetting rid of weeds is always at the top of everyone’s spring/summer garden care priorities. If you don’t start removing weeds now, you’ll spend all summer trying to get rid of them. Everything is having a growth spurt right now, including the weeds. They can be left over ones from last year, or new ones that sprouted in cool weather. Either way – get rid of them now.  It seems like every few hours, some new ones are popping up. Try to dig out the entire plant, including the roots, and pull them up BEFORE they make seeds. They’ll be easier to remove before the ground gets harder when the weather gets drier. If it gets out of control, or you just need a little professional help, our maintenance team is on the job!

What other garden tasks are on your list for this June? Do you have any concerns or questions about your landscape? Reach out to us and ask!