There are a staggering number of willow tree and shrub species found throughout Colorado, and they all seem to have one thing in common: they need a lot of water. With the ongoing drought conditions in our part of the Front Range, does it make sense to add a willow tree to your property?
In this article, we:
- go over the reasons why willow trees are often NOT recommended,
- describe the common native and non-native willow varieties found in Colorado’s Front Range,
- explain when willows ARE recommended, and
- recommend which willow trees to plant in your yard.
Willow Trees Are Not Recommended by Some Organizations
According to a handout created by Colorado State Forest Service, the Colorado Tree Coalition, and the U. S. Forest Service, willow trees are not recommended to plant in the Front Range area of Colorado.
Other tree species they DO NOT recommend planting include:
- Austree (Salix alba x matsudana) (Technically a willow as well)
- Aspen (Populus tremuloides)
- Silver maple (Acer saccharinum)
- Russian-olive (Elaeagnus angustifolia)
- Tree-of-Heaven (Ailanthus altissima)
- Tamarisk (Tamarix spp.)
- White-Barked Birches (Betula spp.)
- Non-native hybrid poplars/cottonwoods (Populus spp.)
- Siberian elm (Ulmus pumila)
Why Willow Trees Are Typically Not Recommended
Willows Need Lots of Water
The willow species, as a whole, is known for being drawn to places with abundant water. That includes swamps, areas near rivers or other bodies of water, or other areas that are known to have and collect a lot of water.
As Colorado is still in the midst of drought conditions, willows are not recommended in general for the Front Range area. Because they need lots of moisture, drought can lead to health issues for the tree. Willows have also been known to compete with other plants for water, so they may end up harming other plants around them.
Willows Have Invasive Root Systems
One of the ways that willows are able to get so much water is through their extensive root systems. While these root systems are helpful for the tree, branching out to search for any available water, the roots can become troublesome in some situations.
Roots cause issues when they seek out water and become embedded in pipes, building foundations, or paved surfaces or when they become invasive and overpower other plants or trees nearby.
As you can see in this handout from the Lefthand Watershed Oversight Group, the invasiveness of a root system can depend on whether the willow tree is native or non-native. Native willow trees tend to benefit the environment around them. In contrast, non-native willows are more likely to become invasive, stealing water and nutrients from surrounding plant life and causing issues with riverbanks.
Willows Sucker Extensively
Willow trees are prone to growing suckers, or offshoots of new trees or branches. While many types of trees are prone to suckering, entire willow trees can literally grow from just a stick in the ground. A branch or stick that has fallen from the willow tree can grow roots and turn into a new tree.
When willows are in the wild, this can be helpful as their short lives mean that new trees are constantly popping up to replace the old. But in a residential or commercial landscape, it just translates to more maintenance, pruning, and digging up any offshoots.
Willows Are Messy Trees
Because willow trees are constantly dropping twigs and branches (that then form suckers), they are considered very messy trees. Leaves, too, often fall off willow trees. Cleanup can be time-consuming and yet is vital, especially during periods of drought or increased wildfire danger.
Willows Have Weak Wood
Willow trees are known to be fast-growing trees and thus have weak wood, prone to frequent breakage. Again, this works in the tree’s favor as it helps it to grow new trees from the pieces that fall to the ground. But for property owners, a willow’s weak wood can be a concern if the tree is located near a home or other structure, especially during high winds or storms.
Willows are Short-lived Trees
Willow trees have a short life, usually only living around 30 years. They have evolved to shoot up quickly. They take in as much water and nutrients as they can, and then die, leaving the suckers and new young trees to replace them.
For property owners who want to invest in their property, it’s far better to choose slow-growing trees that can mature gradually and bring value and benefits to their yard.
Common Willow Trees Found in Colorado’s Front Range
There are a variety of willow trees and shrubs that grow throughout our state. However, many are difficult to identify because the various types tend to hybridize with each other to create new types of willows.
That being said, there are several known types of willows commonly found in the Front Range of Colorado, including:
- Coyote/Sandbar/Narrowleaf Willow (Salix exigua)* – Very common in our riparian areas, grows with narrowleaf willow, rarely grows taller than 15 feet. Spreads easily from underground roots and forms thickets. Often has conegalls caused by conegall midge (Rhabdophaga strobiloides).
- Bebb’s Willow (Salix bebbiana)* – Common in higher elevations, can dominate the riparian areas just below the timberline (around 10,000 feet) and then continue up in elevation 300-400 feet above the tree line. A relatively good soil stabilizer that’s valuable for revegetating stream banks and other disturbed sites. Large shrub grows to 10-15 feet.
- Peachleaf Willow (Salix amygdaloides)* – Native to Colorado, grows up to 40 feet, found in elevations from 3,500 to 7,500 feet. Often found in the foothills area at around 6,000 feet with other willow species.
- Pacific willow (Salix lasiandra spp. lasiandra)* – While native to Colorado, the Pacific willow gets its name because it’s a common plant in the Pacific Northwest. It can grow 15-45 feet tall. It is very often found growing with coyote willow in the creek beds around 7,500-8,500 feet in elevation.
- Crack Willow (Salix fragilis) – Almost ubiquitous along creek banks and marshes here, often looks more like its parent (white willow) because of the fuzziness on the underside of the leaves. Considered the most common non-native species, it can create issues with the Colorado ecosystem and wildlife.
- White Willow (Salix alba) – Sometimes sold as a weeping willow. Can be hard to differentiate from the peachleaf willow.
- Weeping Willow (Salix babylonica) – Not a native tree (it was introduced from China). Note that not all trees labelled “weeping willow” are Salix babylonica, but may be Salix alba ‘Tristis’. It is mostly a backyard tree that was planted into a landscape where the site has water, like a nearby creek or pond.
- Globe Willow (Salix matsudana) – Not as common in Colorado, sometimes seen in ornamental areas in the corkscrew form.
If you plan on adding a willow tree to your property, the kind of willow that you choose will make a big difference. We recommend planting only native trees (marked with * in the list above) that were grown nearby. This will ensure not only that they will thrive in our climate, but that they will help the local ecosystem rather than becoming invasive.
Why You Should Add a Willow to Your Property
Despite all the negative aspects we’ve just mentioned about willow trees, there are still circumstances where you may want to add one (or more!) to your Front Range property.
There’s A River or Body of Water on Your Property
Willows need a lot of water to survive and are often found near streams or rivers. If you have a pond or water that flows through your property, it makes sense to add native willow trees near the body of water.
Some willow species are particularly suited to stabilizing the surrounding soil. If you have problems with erosion, particularly along a creek or river, shrubby willows can quickly spread to keep soil in place along the water’s edge.
You Have Issues with Standing Water or Flooding
For the same reason, willow trees can work to prevent standing water or flooding issues in your yard. If your property was previously a swamp or other moisture-filled area, it might make sense to plant a tree that can handle a lot of water in the ground.
You’re Replacing Non-Native or Invasive Willow Trees
Many non-native plants and trees are taking over our native plant life. This creates issues that can lead to erosion, drought, more wildfires, and poor conditions for native wildlife and pollinators. The less plant diversity in an area, the less habitat is available for birds, squirrels, deer, and other animals that call Colorado home.
One way to stop invasive tree and plant growth is to remove any non-native species from your property. You can replace them with native varieties.
Products Made from Willow Trees
Willow trees have long been a source of material for a variety of products, such as for weaving furniture, fishing nets, and baskets. There are wickers made of willow rods, which are less likely to split than other types of wood.
The leaves and bark of willow trees have been used as a pain reliever and fever reducer since ancient times. In fact, an active extract of the bark, called salicin, can be used to create salicylic acid. A synthetically altered version of salicylic acid was created in 1897 and called “Asprin.”
Willow trees and shrubs are found throughout Colorado, but many of them are non-native and can cause issues, thanks to their need for excessive water, propensity to develop invasive roots, and suckering and littering habits. If you do plan to add one (or several!) willow trees to your property, we recommend one of the native varieties.
Give us a call for more information or to help you identify willows on your own property. We can also help you remove any invasive trees and recommend and plant native varieties for you. You can contact LAM Tree for more information at 303-674-8733 or use our handy online form to request a consultation.
We recommend spring or early fall planting to get your new trees off to a great start. You can always call us for advice on where to plant your new tree(s) and don’t forget that we offer professional tree planting services if you don’t want to do it yourself!
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