All About the Populus Genus

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 Photo by Adobe Stock/kellyvandellen

Twinkling, fluttering, marching, quaking, trembling — these are all words typically used to capture the unique way that poplars, aspens, and cottonwoods stand out in the landscape. All three of these trees are members of the Populus, or poplar, genus, which contains just 35 known species. The word “Populus” is said to come from the Latin “populus arbori,” meaning “the people’s tree.” Another source suggests that the name arises from the Romans planting these trees anywhere people were likely to meet. Trees in the genus provide shelter and food for a wide variety of animal and insect life, and, in death, they’re home to a very specific mushroom species.

Here in Ohio, it’s hard to go anywhere without finding cottonwoods (Populus deltoides), perhaps the most common species in the U.S. Cottonwoods are so much a part of the landscape that they’re almost viewed as weeds. In many communities around the country, members of the Populus genus are considered noxious and are illegal to plant. However, it seems that cottonwoods and their cousins have other ideas, because human efforts don’t appear to be slowing their spread down at all.

Too Much of a Good Thing

There are a few reasons that people tend to look unfavorably at these trees. The first is that not only are they wind-pollinated, but they also use the wind to disperse their seeds. Seed launch day is a big deal to the Populus trees. Their seeds resemble snow in June in some parts of the country. In their travels, the fluffy, white-parachute-clad seeds clog up air conditioners, pool filters, ponds, and more. During this time, many folks see an increase in their allergy symptoms, making the trees an obvious scapegoat. However, it’s more likely that seasonal allergies are triggered by less-obvious grasses blooming at the same time that Populus seeds are falling.

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Another big reason Populus trees are despised is actually one of their strengths. Poplars and cottonwoods are a particularly thirsty bunch. This means that around human habitation, they can seek out drains and septic fields, heave up sidewalks, and create all sorts of other havoc if they’re planted too close to homes. They’re well-adapted to soils where other trees would struggle because of standing water. I planted my cottonwoods, along with maples and walnuts, in an area of our property that was always boggy. For the first few years, the maples were attacked with a variety of fungal infections and displayed pimply leaves covered in red, bumpy growths. While the maples floundered, the cottonwoods stood proud and grew quickly, with their glossy leaves held high. Populus trees produce antifungal phytochemicals that allow them to thrive in wet locations. While they grew, they were also drinking up the water in the area, spreading their roots to make use of the high water table. Over time, this root network began to change the soil quality, and the area dried quickly, allowing the other trees to get a foothold and grow as well. That once-barren area of my property is now a beautiful, young wood. It’s a physical reminder of how useful these trees can be in recovering ecosystems. In fact, they’re well-known for their utility in bioremediation.

If you’d like to grow your own Populus trees, it’s best to start from cuttings. Despite all the seeds and fluff produced by the trees, they don’t seem to have great germination success. Perhaps that’s why they need to produce so many seeds.

Pretty Pioneers

The pleasant slapping sound that accompanies any light breeze brushing past quaking aspens (P. tremuloides) is the result of the long, flattened petioles that attach the leaves to the tree. Aspens prefer mountainous and prairie regions, though, like their lowland relatives, they typically grow on waste ground. They’re another example of the adaptability of the genus. Where cottonwoods and poplars are experts in wet, compacted soils, aspens thrive in areas prone to natural fires. The roots remain alive underground, holding the topsoil in place for other plant species and resprouting from burnt stumps after the fire has passed.

Photo by Adobe Stock/mijun

The most famous aspen is the Pando forest in Utah. Pando is one single organism, spreading by rhizome in a clonal fashion over 106 acres. It’s estimated to weigh about 6,600 U.S. tons, making it the heaviest known organism on Earth. Pando’s root system is estimated at 80,000 years old. It’s among the oldest known living organisms, but it may be dying, and some scientists believe that fire suppression efforts are the main threat to its survival.

The Populus genus is tangled up with human history in a lot of interesting ways. Until canvas became popular in the 16th century, most of the European masterpieces we know were painted on panels of poplar wood, including the “Mona Lisa.” Early settlers in North America are said to have carried seeds of these trees with them as they traveled, planting them as they moved. These early pioneers were also refreshed and encouraged to see stands already growing in new areas, as they signaled the presence of other settlers. The trees would’ve meant food, medicine, means of transportation, and, in many cases, a source of water. Populus trees grow incredibly fast, making good windbreaks, and the wood — one of the softest hardwoods in North America — was prized for canoes. It burns hot, but too quickly to make ideal firewood, and it’s prone to rot when used as building wood. Today it’s mainly used in the making of cardboard, shipping crates, and pallets.

Photo by Getty Images/dbdurden

Populus bark has been used in numerous ways throughout history. Those living where the trees grow recognize the inner bark as a valuable survival food, filling the stomach with fiber, if not nutrition. It, and the leaves of the trees, can be dried and powdered for storage. In lean times, the powdered plant was added to grain flour to stretch the supply. The resulting bread is said to be a touch more bitter, but no less filling.

Health Benefits

The Populus genus belongs to the Salicaceae family. Like willows, another well-known group in Salicaceae, Populus trees produce salicylates, and their inner bark has been used for its anti-inflammatory, pain relieving, diuretic, antiseptic, and astringent properties.

I first became interested in Populus trees because of my specialty in using honey for health. Over the past several years, propolis has become a hot commodity in the natural health arena. Because creating propolis is labor-intensive for the bees, and collecting it is labor-intensive for the keeper, I went in search of a suitable replacement. I quickly found that the buds of poplar and cottonwood trees can be tinctured or infused into oil and used in place of propolis. In fact, in my area, these buds are where honeybees collect a lot of the resin used to produce propolis. Aspens don’t produce sticky buds, and therefore aren’t candidates for this purpose, but all other Populus trees qualify.

Photo by Getty Images/vagrig

The buds of P. balsamifera, or balsam poplar, are the most interesting in terms of medicinal use. In researching the history of this particular tree, I repeatedly came across references to “Balm of Gilead.” P. balsamifera isn’t believed to be the Balm of Gilead referenced in the Bible — that plant is likely to have been either Commiphora gileadensis, the Arabian balsam tree, or a species of Pistacia, the genus including pistachios. The term “Balm of Gilead” seems to have broadened to mean “something with healing or soothing powers.” P. balsamifera is more accurately referred to as the “American Balm of Gilead.” A sort of cure-all, preparations made from the leaf buds can be applied topically to treat muscle soreness, wounds, inflammation, hemorrhoids, and arthritis. Many Native Americans used it internally through teas, and inhaled the smoke for respiratory illnesses and fever.

Using Cottonwood Fiber

Some folks say they’ve spun the fluff from cottonwood seeds into yarn with a lightweight spindle. Cottonwood fluff is very short and fine, so it would make for delicate work, but you could also blend it with cotton or wool to make it easier to spin. It can also be used to stuff pillows, stuffed animals, bedding, and more.

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Collect the seeds and “cotton,” pick out the sticks and leaves, and store it in a warm, dry location. Use cotton hand cards (see “Homegrown, Handspun Cotton” for more hand spinning tips) to smooth the fiber before spinning.

American Poplar Balm Oil Recipe

American poplar, or “American Balm of Gilead,” buds are best gathered in the early spring. You’ll want to catch them just before the leaves burst, so go out after you’ve had a few warm days. Test the buds before you pick them. If they’re gummy, but very firm, they aren’t quite ready yet. If they’re tacky and squirt a bit of yellowish-gold resin when you squeeze them, they’re perfect for picking.

  • Clip buds here and there from the tree. Remember that they’ll give rise to leaves. You can also look for limbs that’ve just been brought down by a storm, or those that need to be trimmed.
  • Spread the buds in a shallow basket or over a screen, and allow them to dry in a shady spot outside or in a spare room.
  • Fill a jar 3/4 full with slightly dried buds, and cover with extra-virgin olive oil. Firmly tighten the lid.
  • Place the jar somewhere you’ll see it often. Shake it every once in a while to keep everything evenly distributed.
  • After at least 4 to 6 weeks, or up to 1 year, strain the buds out of the oil and compost them.
  • Store your labeled oil in a sealed jar or bottle in a cool cupboard away from direct light, and use as needed.

Dawn Combs, M.A. ethnobotanist, is co-owner of the award-winning family herb farm Mockingbird Meadows and formulator of its Soda Pharm syrups. She’s also the author of Conceiving Healthy Babies and Heal Local.

Mother Earth Gardener
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