Aspen Trees

As you begin to plant and take care of your trees, it may become apparent that they look weak or even bare underneath. In most cases, this is often how it appears because the soil below is bare. With this comes the question, “What plants can I put under my aspen tree?” 

Some of the most common examples of plants that you can put under your aspen tree include cosmos, bachelor’s buttons, and zinnias, which require fewer nutrients than typical flowers. Low crawling herbs such as soapwort, sedum, thyme, mint, and catnip will also grow well under your aspen tree.

Read on to learn more about what Aspens need/want to grow and what plants you can grow around them to improve looks and even the health of your tree!

Basic Aspen Tree Growth 

To understand what plants you can grow near your Aspen, it is first important to know how your Aspen grows, as you don’t want to accidentally impede its growth through planting competition. 

As for growth rate, Aspens can grow up to (or often more than) 24 inches per year. This is astonishing when compared to other slow-growing plants. This is also good to keep in mind as you don’t want to plant any sun-loving ground covers. Your growing Aspen could easily shade them out!

Compared to other trees, Aspens have fairly shallow root systems. On average, most Aspen roots only grow down about 12 inches; however, they all tend to sprawl and spread outward very quickly. 

In addition to the vigorous spreading of roots, Aspens tend to propagate and root quickly. This is important to know if you plan on growing other things near them, as they do pose some risk of propagating and shading/competing with your other plants. 

Not exactly a team player, these Aspens!

Requirements For Healthy Aspen Trees

Fall color of aspen trees.
Fall color of Aspen trees.

Aspens have a few basic requirements for healthy, strong growth. For the most part, however, they can be pretty adaptable and strong in most areas. 

Aspens have some standard requirements (among most species) that revolve around things such as soil qualities and water retention, making them pretty easy to adapt to and care for. 

To start, Aspen trees want their soil to be well-drainingThis means that they want a soil that is looser/has more particulates, such as sand, compost, and other organic material. 

Along the same line, Aspens require well-draining environments, meaning they want less water than other plants. This is important to think about when incorporating other plants, as some of their requirements may be the opposite of your Aspen’s. 

In addition to this, Aspen trees also like their soil to be slightly acidic. This can be accomplished through using things like “acid-lovers mix” or pine straw mulch. This is also a good aspect to think about, as it may also interfere with the growth of other plants you wish to pair with your Aspen. 

Pairing Aspens With Different Plants

When choosing additional plants to grow around your Aspens, it is important to think of the requirements of both. In doing so, you can ensure that both your plants and tree will be happy and healthy. 

In general, planting things with opposite or complementary requirements to your Aspen tree will lead to the most success. For example, planting something that prefers shade underneath your tree would most likely work great, as your tree can get full sun while providing the plant with proper shade. 

As they say, opposites attract!

Pairing Shade Requirements For Plants Under Aspen Trees

Upper view of the Aspen trees in the fall season.
Upper view of the Aspen trees in the fall season.

One of the most important things you need to pair is the shade requirements of your Aspen tree and companion plants. As sunlight is one of the most important factors a plant needs, getting the incorrect levels can easily lead to one of your plants becoming weak. 

Going along with this, it is normally best to pair a plant that tolerates, or even likes, shade with your full trees.

This is because, in most cases, the tree will tend to be way larger and cast a large area of shade. For most plants, this can be harmful; however, if you preemptively plan by putting shade-loving plants, you will have completed companion planting.

Pairing Water Requirements For Plants Under Aspen Trees

Similar to shade, water is another requirement that is the limiting factor to pairing plants and Aspen trees together. If two plants near each other have vastly different water needs, one of them is bound to not be in its optimal conditions and will most likely suffer from it. 

Instead, if you put plants with similar water requirements to Aspens near your tree, both will most likely flourish and grow strong and healthy together. 

Pairing Soil Requirements For Plants Under Aspen Trees

Although less important than water and sun, soil can be another factor that limits plant pairings. With soil comes lots of other factors such as pH, nutrients, etc. These can have many positive or negative effects on plants and trees. 

With this, if you plant companion plants near your Aspens that have similar soil, pH, nutrient, and other similar requirements, both will most likely enjoy their environment and grow well together! 

Will Plants Under Aspen Trees Harm The Tree?

Another important factor to look at is safety with plants. This doesn’t refer to your safety but instead refers to the safety of your Aspen tree itself. With this, some companion plants can compete with your Aspen, or in worse cases, even kill it. 

Going along with this, what are some concerns that should be thought of when putting companion plants near your aspens? 

Vines and Chokers Harm Aspen Growth

Vines and choking plants can be one of the worst things for aspen trees. This category of plants refers to things like morning glory, blackberries, or English ivy. Although they are beautiful, most of them can easily compete with trees and even cause them to struggle with basic things like light and water requirements. 

In most cases, vines and chokers can physically block your Aspen’s roots or trunk and can also crawl upwards and grow around branches, blocking the much-needed light from your Aspen’s leaves. 

Invasive Plants Can Be Bad For Aspen Trees

Another thing to think about is invasive plants. These plants are those that are not usually native to your area, meaning that in some cases, they can easily take over Aspen trees and become rampant, even dominating over some of the other native plant species in the area. 

With this, it is important to research the native and invasive plants in your area before you try to companion plants near your aspen tree! 

6 Best Plants to Put Under Your Aspen Tree

Now that we know what Aspen trees need and what to avoid when companion planting, we can now look at the specific plants that you can (and should!) put under your Aspen tree, as well as how to plant them. 

Sedum Varieties Under Your Aspen Tree

Decorative garden plant Sedum prominent (lat. Sedum spectabile.)
Decorative garden plant Sedum prominent (lat. Sedum spectabile.)

Sedum is a great plant to put near your Aspens. It is simple to care for, normally not requiring much. In addition, it has a root system that does not normally compete with your Aspens. 

In addition, creeping varieties are well suited to part-shade, making them excellent to plant with large Aspens that may block out some of the sun.

They also come in lots of shapes, sizes, and colors, which make them great to use in flower and show gardens that may need special looks/themes. 

Thyme Varieties As Aspen Tree Companion Plants

green background with a twigs of a thyme closeup
Close up of thyme plant.

Thyme is another great option to plant near your Aspen trees or in your garden in general.

Thyme tends to grow lower to the ground as a cover crop, having shallow roots that hold on and retain soil while also not competing with larger organisms such as your Aspen. 

In addition, thyme plants normally don’t require many nutrients or other compounds, so they won’t compete with Aspen trees for any nutrients either. Another benefit of thyme plants as companion plants is that they are very aromatic and lovely for your garden and kitchen. 

Overall, thyme might be a great option for you, especially if you are looking for plants to cover a wider area or for herbs that you can use in your kitchen!

Mint, Catnip, Other Herbs Grow Well Under Aspen Trees

Close up of catnip, green herb growing in a container
Close up of catnip, green herb.

Similar to the idea of thyme, other herbs such as mint, catnip, or rosemary could also be planted near your Aspen trees. They have similar benefits, such as not having rigorous root systems, not requiring too much water, and not competing for vital nutrients. 

In addition, all of these herb options are great for the fact that you can use them in the kitchen as well, possibly maximizing some of the space that you use in the garden. Another benefit of these plants is that they are aromatic, and their flowers can also attract beneficial insects if you are also planting near a vegetable garden. 

One great option for herb varieties is this SEEDRA 12 herb seed variety pack, which can be used to companion plant near your Aspen!

One drawback of some of these plants, mint, in particular, is that they can be vigorous in the speed and size in which they grow.

While they may not compete underground with your Aspen, they do have the ability to spread far and wide very quickly, possibly causing you some trouble or unneeded work with trimming and maintaining the area. 

Cut Flowers Grow Well Under Aspen Trees

Red zinnias in full bloom
Red zinnias in full bloom.

Cut flowers are another great option to add to your companion planting list for Aspen trees. “Cut flowers” refers to the common list of flowers that are grown for arrangements, such as cosmos, bachelor’s buttons, and zinnias. 

All of these options are great because, normally, they do not require lots of water, and they do not have super vigorous root systems that could compete with your Aspen. 

In addition to this, cut flowers do not usually require too much sunlight (although they don’t hate it), or too many nutrients, meaning they won’t compete too much with your Aspen in those regards either. 

Similar to the herbs, cut flowers can also be harvested, cut, and used in arrangements or other home endeavors, making them multifaceted and useful. Another benefit is that they can attract beneficial insects if you are working in or near a garden!

Another pro to cut flowers is that they come in many species, shapes, sizes, colors, scents, etc., making them great for someone who has specific wants/needs with color, size, and use. 

Similar to the herbs, many cut flowers can be found in packs, such as this Botanical Interested Cut Flowers Seed Collection.

Baby’s Breath Plants Under Aspen Trees

Beautiful flowering close-up of Alpine Gypsophila flower or Creeping Baby's Breath Gypsophila repens.
Close-up of Alpine Gypsophila flower or Creeping Baby’s Breath Gypsophila repens.

Baby’s breath is a plant that may not often be thought of; however, it can be very useful in companion planting with Aspen trees. 

Baby’s breath plants create a great puff of white color through their small and delicate flowers, making them unique and fun to plant with Aspen trees. In addition, their roots can hold in and retain the soil without competing for things like nutrients or water.

Another thing to think about is that baby’s breath may need full sun but can still be healthy in partial shade, so you may have to play around with planting them before fully committing. 

Artemisia’s Look Gorgeous Under Aspen Trees

Artemisia (mugwort) plant.
Artemisia (mugwort) plant.

Artemisia (mugworts) is another unique and uncommon plant that can be grown with Aspens. According to most sources, they are drought-tolerant and will not compete for too many nutrients or water. 

In addition, many avid gardeners love to plant artemisia with their Aspens for their specific color. Most people cite that the silvery color of the artemisia plants highlight and make the undertones of Aspens leaves look gorgeous, making them a great companion plant. 

Overall, artemisia may be a great option for you, especially if you are looking for a classic pairing that has been tested and proven to boost the natural beauty of your Aspen tree. 

Salvia Varieties Plant Well Under Aspen Trees

Blue salvia (sage) flower in blossom.
Blue salvia (sage) flower in blossom.

Some varieties of salvia, like sage, are another great option to plant near your Aspens. Like most other plants on this list, they are pretty easy to take care of and are not known to compete or choke out other plants such as your Aspen tree. 

In addition, salvia comes in many different varieties that exhibit many different colors and sizes, making them infinitely customizable for the home gardener.

Another pro is that salvia has a bit more height when compared to other plants on this list, giving them a unique and not often seen beauty in companion planting. 

During the spring and summer seasons, big-box gardening stores and small nurseries often carry many varieties of salvia seedlings, along with many varieties of salvia seeds, meaning they are highly accessible to use in any format or size. 

In the end, salvia is another great option for those who are beginners in gardening/companion planting and for those who may want to simply buy a plant from the store and put it in the ground. 

That’s A Wrap!

In the end, Aspens are pretty unique trees that can add the perfect touch to just about any home garden. They are versatile and usually have a few simple requirements, making them incredibly easy and rewarding for any home gardener to take care of!

In addition to this, you may want to plant companion plants near your Aspen to fill in the space or even create a symbiotic relationship. In doing so, there are multiple factors that you should think about, such as the light, soil, and water requirements of both your Aspen and companion plant. 

There are also a few other things to think about, such as if your companion plants are invasive in your area or if they are known to vine and choke out large things such as trees and shrubs. 

Overall, there are a few main companion plants that are well known to form great relationships with Aspens, such as herbs, sedums, salvias, and artemisia! 

So get out there and have fun planting with your Aspen tree! 

References

Cunningham, S. J. (1998). Great Garden Companions. Google Books.

Légaré, S., Bergeron, Y., & Paré, D. (2005). Effect of Aspen (populus tremuloides) as a companion species on the growth of black spruce (picea mariana) in the southwestern Boreal Forest of Quebec.

Sjödin, A., Wissel, K., Bylesjö, M. et al. Global expression profiling in leaves of free-growing Aspen. BMC Plant Biol 8, 61 (2008).

Rahman, M. (2021). Bioscience Biotechnology Research Communications. Vol 14. No. 05 242–244.

When you think of an aspen tree, you are most likely thinking of a tall, white-barked, slender tree that has golden-yellow leaves in the fall. This is a Quaking Aspen. But did you know there is another, less-well-known aspen tree growing in North America?

The quaking aspen and bigtooth aspen are the two types of aspen trees found in North America. There are a few ways to tell these trees apart, including the shape of their leaves, the bark color and texture, the height of the trees, and where they are found in North America.

Aspen trees are beautiful to see and are quite unique because they can clone themselves. Read on to discover the 9 differences between bigtooth aspens and quaking aspens.

Are Aspens And Quaking Aspens The Same?

There are six species of aspen trees, but only two are found in North America. The quaking aspen and the bigtooth aspen. These trees are very closely related to poplar trees, both of which are part of the genus Populus.

Aspen trees are only differentiated from poplar trees by their scientific classification. Even then, the lines become a little blurred. Although grey poplar and white poplar are different species, they are still part of the Populus genus and are even classified in the same section as aspen trees.

So, are aspens and quaking aspens the same thing? Yes! It is similar to asking if a grey wolf is a wolf… yes, of course! But a grey wolf is a species of wolf, just like  quaking aspen is a species of aspen. 

Zooming out further, aspen trees are part of the willow tree family. These include willows, poplars, aspens, and cottonwoods.

Aspens are deciduous trees, meaning they lose their leaves in the fall. According to Bryce Canyon National Park Service, the aspen flowering season is in May and June, but aspen tree seeds rarely successfully establish themselves. Instead, they reproduce by cloning themselves. 

Wait, what? Don’t worry, more on that later…

First, let’s check out the major differences between bigtooth aspens and quaking aspens. We’ll also go over how these trees are similar.

9 Differences Between Aspen And Quaking Aspen

The differences between trees may not be as obvious as the differences in animals. But if you look closely, you can see subtle differences that will clue you into what type of aspen tree you are looking at!

Along with the descriptions below, you can use something like Mark Mikolas’s Beginner’s Guide to Recognizing Trees of the Northeast. This can further aid you in your quest to differentiate one aspen from another.

With location maps for each species and over 400 pictures, you are sure to recognize more of the trees around you!

CHARACTERISTICQUAKING ASPENBIGTOOTH ASPEN
LeavesHeart-shaped with small, jagged teeth on the outer rimHeart-shaped with large jagged teeth on the outer rim. Larger leaves than quaking aspen
BarkWhite to yellowish/grey-whiteOlive green to brownish green
Height20-80 feet60-80 feet
Width3-18 inches in diameter8-10 inches in diameter
RangeAll across Canada & Alaska, Northeast & Northcentral U.S. with some patches in the westSoutheast Canada & Northeast/Northcentral U.S.
Environmental ConditionsMountainous regions up to 11,500’ elevationGently sloping terrain, sandy loam, up to 3,000’ elevation
Seed DispersalCatkins; dispersal is approximately May-June. Usually before bigtooth aspensCatkins; dispersal is approximately May-June. Typically 1-3 weeks after quaking aspen dispersal
Longevity50 years for individuals60-70 years for individuals
NameQuaking - named for the way the leaves appear to quake/tremble in the slightest breezeBigtooth - named for the tooth-like serrations on the leaves

Aspen & Quaking Aspen Leaf Difference

The first difference we’ll look at is the leaves of the tree. You’ll have to look close in the spring, summer, and early fall to use this to differentiate. Both quaking and bigtooth aspen are deciduous trees, so they will not have leaves in the winter.

Bigtooth aspen leaf.
Bigtooth aspen leaf.

According to NCR Forest Management, both trembling aspen and bigtooth aspen have heart-shaped leaves that are green in the spring and yellow, golden, or (more rarely) red, in the fall.

The biggest difference will be in the outer edges of the leaves. Quaking aspens will appear smooth but have small jagged edges. Bigtooth aspen will have much more pronounced edges, hence the name ‘bigtooth’ aspen.

Another difference in the leaves is the size. Bigtooth aspen leaves are bigger than quaking aspens, reaching up to five inches in diameter while quaking aspens are only two to three.

Aspen & Quaking Aspen Bark Difference

Using bark to tell the difference between trees is a great tool to have in the winter when it’s impossible to see the leaves because, well, they’re all on the ground!

The bark of quaking aspen is typically white with black scars running along the width of it. These scars are where lower branches were naturally self-pruned while growing.

quaking aspen trees.
Quaking aspen trees.

The bark of bigtooth aspen is more of a greenish color, according to the Maine Forest Service, but smooth in appearance except in older trees. Older trees may have furrows in the bark, especially at the base of the tree.

The bark of both the bigtooth and the quaking aspen has a remarkable property – they can photosynthesize in the winter! While most other trees are being lazy and dormant during the winter, aspen trees are still hard at work, growing and producing sugars and carbohydrates!

This is possible because the bark is so thin on aspen trees. Beneath this thin layer is a green layer that is filled with chloroplasts needed for photosynthesis.

Aspen & Quaking Aspen Height Difference

Aspens are medium-sized trees. They’re certainly not grouped with giant sequoias, but neither are they secluded to small, shrub-sized trees.

That being said, quaking and bigtooth aspens differ in the final height they will reach at maturity. In general, both trees are considered fast growers, especially because of their ability to continue growing in winter.

Quaking aspens can reach a height of up to 80 feet but typically range somewhere between 20 and 80 feet. Bigtooth aspens also max out around 80 feet, but they are often taller, averaging around 60 to 80 feet.

Aspen & Quaking Aspen Width Difference

As with height, the diameter of quaking and bigtooth aspens differ slightly, giving you a good indication if you are unable to identify the leaves.

Quaking aspens are usually 3-18 inches in diameter according to the U.S. Forest Service. Bigtooth aspens average 8-10 inches. 

So, while bigtooth aspens are generally taller than quaking aspens, they are usually thinner around the middle.

Aspen & Quaking Aspen Common Range

Quaking aspens are widely distributed in the United States. In fact, they are the most predominant deciduous tree in North America!

In terms of range, quaking aspens are found throughout Canada and into Alaska. They can be found as far south as Mexico, but the largest continuous stands are found in the northeast and the north-central regions of the U.S. 

Patchy areas in the west can be found, especially in Utah and Colorado.

The bigtooth aspen is less widely distributed than the quaking aspen. They are found primarily in the northeast and north-central United States. You can find them in southeast Canada as well.

In areas where quaking aspen and bigtooth aspen coexist, they often grow near each other or in the same stand.

Aspen & Quaking Aspen Preferred Environmental Conditions

Some things that affect a tree’s ability to grow include PH, precipitation, and soil type. For aspens, they’re like coyotes and will thrive almost anywhere!

Bigtooth aspens prefer gently rolling hills, floodplains, sandy areas, and the bottom of upland slopes. But really, they’ve been found in almost every soil type and condition. They have a soil PH limit of 4.0, which is pretty acidic!

These aspens are found at lower elevations than quaking aspens, typically thriving at elevations lower than 3,000 feet, according to the USDA Fire Effects Information System.

Quaking aspens are more at home in the mountains. They prefer mountainsides, mesas, plateaus, and can be found at the bottom of valleys and canyons. You might spot one up to 11,500 feet, which is why a lot of leaf peepers love to go to the Colorado mountains to see the aspens change!

In terms of soil, quaking aspens also like sandy conditions, but will thrive in shallow and rocky terrain as well.

Both quaking and bigtooth aspens need moist, well-drained soil to thrive and expand their root systems. Both trees are shade-intolerant, although bigtooth aspens can tolerate shade better than quaking aspens.

Aspen & Quaking Aspen Seed Dispersal

Flowering branches of the aspen tree with aspen tree catkins.
Aspen tree catkins.

Both quaking and bigtooth aspens are dioecious. Soooo what does that mean? All dioecious means is that there are distinct male and female trees, similar to how boxelder trees are.

Flowering for quaking and bigtooth aspens begins around March-April. The bigtooth aspen has a shorter duration of active flowering than the quaking aspen, and seed dispersal happens up to 3 weeks after the quaking aspen disperses its seeds.

The fruits of both trees are called catkins. These catkins contain pear-shaped seeds with white tufts. Each tree can produce up to 1.5 million seeds per season!

Believe it or not, almost none of these seeds will turn into full-grown aspens. Conditions have to be perfect for an aspen seedling to grow, and these conditions are rarely met. This is mainly because of the tree’s extreme intolerance to shade. It often gets overshadowed by larger trees or saplings.

Aspen & Quaking Aspen Average Longevity

Aspens are not long-lived trees. Unlike the mighty oak, which some species can live for centuries, aspens rarely live beyond 100 years.

According to the National Wildlife Federation, quaking aspens typically live for about 50 years. Bigtooth aspens average 60-70 years before they begin deteriorating.

Most tree deterioration is caused by fungus rot or pests such as gypsy moths. Quaking aspens are more susceptible to disease and pests than bigtooth aspens.

Aspen & Quaking Aspen Name Differences

This difference is a bit of a cheap shot, but names are important!

Populus tremuloides, the quaking aspen, is so named because of the way its leaves flutter with the slightest breeze. 

This is because the leaves are attached to branches by a thing called a petiole that is long and flat. This petiole allows the leaves to swivel even with the lightest touch of wind. Hence the name quaking or trembling aspen.

The bigtooth aspen is named after the large tooth-like serrations that are found on the leaves. The bigtooth aspen also has petioles that allow the leaves to swivel in the wind, but it’s not as impressive as on the quaking aspen.

What’s So Special About Quaking Aspens?

Everyone seems to make a fuss over these trees. Is it their leaves? Their stark white bark? What’s so special about quaking aspens?

Probably the most unique feature of quaking aspens is Pando. Pando means “I spread” in Latin and refers to the largest organism on earth – a stand of quaking aspen trees!

I’m sure you have a lot of questions bursting at this point: how can an aspen tree be bigger than a whale, for starters.

A single aspen tree is not bigger than a whale, but aspen trees have a unique way of reproducing called suckering. When a stump or root system dies, new stems can grow from them through a unique process done only by aspen and some poplar trees.

The most interesting part? These new stems that eventually grow into new trees are a clone of the original tree. This means these clones are identical to the parent trees in terms of genetic makeup.

Meaning…it’s all one organism! Pando is still being argued over in the scientific community, as a few people aren’t willing to call the cloned trees part of the same organism, but still. It’s pretty amazing, right?

Pando weighs in at about 13 million pounds and covers 106 acres. It came from a single male aspen tree, but now contains over 40,000 individual trees! Pando is located in Fishlake National Forest in central Utah.

Because of this amazing ability to clone itself, quaking aspens are often the first trees to reestablish after disasters like flooding and forest fires. Once the fires or floods have raged through, fresh shoots will develop quickly from the dead stumps or dying root systems.

This is true for areas that have been affected by mining as well. As long as the parent tree is still present, aspens will flourish in the area! Although, after 30-40 years, they will begin being out-competed by taller trees that cast shade on the aspens, killing them off.

Wrapping Things Up!

That’s all we have for now on aspen trees! To recap, there are two types of aspen trees in North America: Quaking aspens and bigtooth aspens.

Quaking aspens are the most widespread and well-known aspens, distinguished by their white bark and small, heart-shaped leaves. Bigtooth aspens have greenish bark with bigger, jagged-edged leaves.

Both trees can clone themselves through suckering, but if not, they can produce millions of seeds each year to establish new trees.

All in all, aspens are pretty unique and are beautiful to see in the fall when their leaves turn golden yellow. They are a keystone species, and many plants and animals would be out of home and shelter if not for the mighty aspen stands!

References

Campbell, R. B., & Bartos, D. L. (2001). Aspen Ecosystems: Objectives for Sustaining Biodiversity [USDA Forest Service Proceedings] [P299-305]. https://www.fs.fed.us/rm/pubs/rmrs_p018/rmrs_p018_299_310.pdf

Davis, D. D., & Frontz, T. M. (2003). Growth and mortality of bigtooth aspen trees stressed by defoliation [General Technical Report]. North Central Research Station. https://www.fs.usda.gov/treesearch/pubs/15850

Painter, L. E., Beschta, R. L., Larsen, E. J., & Ripple, W. J. (2015, January 01). Recovering aspen follow changing elk dynamics in Yellowstone: evidence of a trophic cascade? Ecology, 96(1), 252-263.

Shepperd, Wayne D.; Binkley, Dan; Bartos, Dale L.; Stohlgren, Thomas J.; and Eskew, Lane G., compilers. 2001. Sustaining Aspen in Western Landscapes: Symposium Proceedings; 13–15 June 2000; Grand Junction, CO. Proceedings RMRS-P-18. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 460 p

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