Bigtooth Aspen

Populus grandidentata

Description & Overview

Bigtooth Aspen is one of, if not the fastest-growing native trees in Wisconsin. It’s an early colonizer of prairies and woodland edges but prefers drier sites than its cousin, Quaking Aspen. Named for the large teeth on leaves that shimmer in a summer breeze and turn a gorgeous golden yellow in fall. If you have the space for its inevitable suckering, Bigtooth Aspen is a wonderful addition to any upland environment.


Core Characteristics

Mature Height: 40-70 feet
Mature Spread: 10-20 feet
Growth Rate: Very Fast
Growth Form: Columnar, coarse
Light Requirements: Full Sun
Site Requirements: Adaptable, intolerant of flooding
Flower: Insignificant, dioecious, small catkins emerge in spring before leaves
Bloom Period: April
Foliage: Blue-green, coarsely toothed, lighter below
Fall Color: Golden yellow
Fruit Notes: Insignificant, very small, good crops every 2-3 years

Suggested Uses:

Due to the suckering habit and large mature size, Bigtooth Aspen needs to be planted where it has room to grow. Avoid planting near utilities, structures, or restricted planting areas. The tree is intolerant of flooding (and fire – if that’s a regular occurrence in your landscape). If you have a wetter space, then opt for Quaking Aspen. The opposite is also true; Bigtooth Aspen is the best native Populus selection for dry sites and easily outperforms its cousin in growth and disease resistance.

Bigtooth Aspen shines as a windbreak or screen where winter coverage isn’t important. It also fills an important niche as an early-successional colonizer in drier sites. You’ll usually find it invading prairies and old farm fields along with Elms, Boxelder, and Pin Oak. Although a tough tree, Bigtooth Aspen doesn’t get our Urban Approved accolade due to its thin bark and propensity to suckering. While it’s not a great option for a 4’ wide terrace, don’t be afraid to consider using it along freeways or in park settings where its mature size is appropriate.

Wildlife Value:

In its native range, Bigtooth Aspen is an essential species for grouse habitat. In fact, it’s vital that there are multiple age classes of the species; there must be areas of young new growth, intermediate growth, and older, mature growth to provide adequate shelter and breeding grounds for grouse.

The young shoots of new root sprouts are an important food source in winter for members of the Cervidae family: deer, moose, elk, etc. The level of browsing by these large mammals can limit the spread of Bigtooth Aspen, much like Elk restricted the regrowth of the related Quaking Aspen in Yellowstone National Park. The aspen there was only able to regenerate once wolves were reintroduced to Yellowstone’s ecosystem. You can read more about this fascinating story at the National Park Service’s resource on Wolf Restoration (archived to preserve the content).

Of course, Bigtooth Aspen isn’t just for large animals. The tree also serves as an important host to Viceroy and Eastern Tiger Swallowtail caterpillars. While the Eastern Tiger Swallowtail (Papilio glaucus) has a wide range of larval hosts (cherries, magnolias, birch, etc.), the Viceroy (Limenitis archippus) requires trees in the Salicaceae family (Willows and Aspens) for its caterpillars.

Maintenance Tips:

Bigtooth Aspen has better growth and disease resistance than Quaking Aspen on drier upland sites. However, any new tree will require water and Bigtooth Aspen is no exception. Due to its rapid growth, you should watch the tree for the first year to ensure it doesn’t become drought-stressed.

Like all smooth-barked trees, Bigtooth Aspen requires trunk protection in fall through winter to prevent buck rub. This can damage and weaken the trunk of the tree and encourage suckering. Protection should be applied until the tree is more than 6” in trunk diameter. However, if the goal is to restore a natural area, you can use buck rub to your advantage to encourage colonization. In this case, the tree should be protected for the first 3- to 4-years to ensure its root system can support sucker formation.

Bigtooth Aspen isn’t susceptible to being blown over (windthrow), but tops and branches can break where there are old wounds. Therefore it’s important to protect the trunk from deer damage and buck rub as the scarring will result in weaker wood that is more prone to breakage.

Are you worried about suckering? Bigtooth Aspen re-sprouts using the same mechanism as Quaking Aspen. You can read more about it on our Qaking Aspen profile in the ‘Maintenance Tips’ section.

While Bigtooth Aspen grows fast, you may want to stem that growth (ha! Pun intended) for the first few years by nipping the tip back by 1/3 to 1/2. This prevents it from becoming too top-heavy and encourages heavier branching. Long term this isn’t a problem, but when you’re planting a #5 RM tree with a root mass only 12” wide, a heavy top can cause it to lean in its planting location. Top pruning seems to have better results than staking when it comes to keeping the tree straight. By year 2 this should not be an issue as the tree should have been rooted in well.

We invite you to check out the Arborist For Hire lookup at the Wisconsin Arborist Association website to find an ISA Certified Arborist near you.

Pests/Problems:

Bigtooth Aspen can be affected by a wide range of pathogens and insects. However, the tree’s vigor and suckering habit combined with its relatively short lifespan (40-80 years depending on the site quality) means that these diseases aren’t worth managing in the long run. Below are some of the more common or serious afflictions.

Hypoxylon canker is a problem for all aspen but Bigtooth Aspen is significantly more resistant to the disease than its cousin Quaking Aspen. In forestry, the usual solution to Hypoxylon is to cut and burn the site, then plant something else. In the landscape setting, I’d recommend the same course of action as there’s no good treatment for the disease. However, both situations are based on ‘production’- for forestry, it’s quality pulpwood, and for landscaping its quality aesthetics. If you’re managing wildlife, then the need to remove and destroy the infected trees may not be necessary. If you feel otherwise, though, let me know!

Occasionally the tip growth of Bigtooth Aspen can die back and form a distinctive shepherd’s crook. This is purely cosmetic. Removing the crook may be useful on a young tree from an aesthetic standpoint, but it’s hardly worth managing on larger plants or in a colony.

Tent caterpillar feeds on Bigtooth Aspen leaves and can defoliate the trees for 2-3 years. This isn’t any cause for concern, however, since the tent caterpillar populations tend to boom and bust every 3-4 years. In the off years, the trees can thrive and restore plenty of the energy they missed out on while the caterpillars ate their fill.

Leaf Lore:

Quaking Aspen and Bigtooth Aspen can hybridize where their ranges overlap, but this is rare due to their staggered flowering times. Bigtooth also differs from Quaking Aspen in its bark color (yellow-green instead of gray-white) and leaf size (larger for Bigtooth). Belowground, the suckering roots are deeper for Bigtooth than in Quaking aspen, which is likely what gives them the advantage in dry sites while making them intolerant of flooding.

The seeds of Bigtooth Aspen are super small and numerous; it takes over 2.5 million seeds to make one pound, and a single stem can produce 1.5 million seeds in an average year. However, reproduction by seed is rare as they have only a brief window of viability (one to two weeks). During this time, the seeds must fall on bare mineral soil, have adequate moisture to encourage germination, and experience temperatures that are not too cold or warm. In the wild, this means that Bigtooth Aspen you find in groups are almost always colonies. In the landscape, this means that you are unlikely to have Bigtooth Aspen volunteering everywhere from seed (although suckering from the original planting is a different story).

The primary method of regeneration for Bigtooth Aspen is through root sprouting, also called suckering. In forest settings, this is usually accomplished by clearcutting, wildfire, or catastrophic weather like blowdowns. When these disturbances occur and allow light to hit the vast root system of a Bigtooth Aspen colony, they respond by producing between 3200 to 24000 stems per acre. That means there’s one stem roughly every 20 inches.

Bigtooth Aspen also fulfills an important role in soil stabilization. Their coarse branching lets lots of snow hit the ground over winter in contrast to our evergreen forests. This snow insulates the soil against freezing and thawing and allows snowmelt to flow into the soil rather than over it when spring arrives. Bigtooth Aspen is hugely important to mitigating spring snowmelt and subsequent flooding. It’s an excellent tree choice where soil stabilization is a priority.

Commercially, Bigtooth Aspen is primarily a source of pulpwood for paper production (say that five times fast), but good quality trees can be used for veneer wood and timber. Like Quaking Aspen, Bigtooth Aspen wood is not prone to splintering, making it a great choice for benches and other ‘high-contact’ wood surfaces. The tree can also be a source of firewood. It’s wet when harvested and burns rapidly when dried, but it’s easier to split an Elm. While it’s not my first choice for the woodstove, it’s a useful and abundant fuel source in winter.

Companion Plants:

As an early successional species that produces only partial shade, Bigtooth Aspen pairs well with other partial-shade trees and shrubs. Native cherries (Black, Choke, Pin), Nannyberry Viburnum, Prickly Ash, and Ironwood are all common native companions to the tree. For a more open aesthetic, sedges make a beautiful groundcover between an abundance of straight stems. Peppering in a few native perennials like Bigleaf Aster, Prairie Blazing Star, Spikenard, and Stiff Coreopsis are easy ways to make sure your landscape provides ample habitat and food to our pollinators.




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