Why does my tree shed white fluff?

That is the seed dispersal mechanism of female poplars, which use cottony tufts to travel on the wind.

Can I plant this near my house?

No, their aggressive root systems can easily invade sewer lines and crack foundations.

Plant guide

Cottonwood.

Populus

Pronounced POP-yoo-lus

Also known as Aspen, Cottonwood, Poplar, Cottonwood, Poplar, Poplars, aspen, cottonwoods

Populus nigra — Photo by Francesco Santoro (CC BY) via iNaturalist

Poplars are fast growing, deciduous trees known for their rapid height gain and often trembling leaves. They thrive in moist soils and are frequently found near water sources in nature. These trees provide excellent shade but require plenty of space for their extensive root systems.

Another photo of Cottonwood — Photo by Tony Rebelo (CC BY-SA) via iNaturalist

At a glance

Care level: Easy
Plant type: Deciduous tree
Light: Full sun
Indoor light: Direct sun
Water: Every 7 to 14 days
Mature size: 15 to 30 meters
Growth rate: Fast
Hardiness: USDA 2 to 9
Bloom time: Early spring

Care

Plant these trees in a location with ample space to accommodate their wide root spread. Keep the soil consistently moist, especially during the first few years of establishment. Watch for signs of leaf spot or rust, which can occur in humid conditions.

Watering: Keep the soil consistently moist but not waterlogged.
Feeding: Apply a balanced fertilizer in early spring before new growth begins.
Pruning: Prune during the dormant winter season to remove dead or crossing branches.
Repotting: Repotting is generally only applicable for young saplings in containers.
Soil: Moist, well draining, loamy soil
Soil pH: 6.0 to 7.5
Temperature: -40 to 35°C
Humidity: 40 to 80%
Drought tolerance: Low
Lifespan: Typically 30 to 50 years.
Deer and rabbits: Low

Safety

People: The bark contains salicin, which can cause reactions in people sensitive to aspirin.
Children: The brittle branches can break easily in high winds, posing a falling hazard for children playing underneath.
Contact allergens: The sap can cause mild skin irritation in sensitive individuals.
Airborne allergens: The airborne seeds, often called cotton, can be a significant respiratory irritant during late spring.
Edibility: The buds and bark are not for human consumption and may cause digestive distress.

How to identify it

Triangular or heart shaped leaves
Leaves often tremble in light breezes
Bark becomes deeply furrowed with age
Catkins appear before leaves in spring

Height: 15 to 30m
Spread: 6 to 12m
Leaves: green, yellow, deciduous
Flowers: red, yellow, green, 2 to 10cm
Fruit: white, brown, late spring

Problems to watch for

Poplar BorerCommon
RustCommon
AphidsUncommon
CankerUncommon
CaterpillarsUncommon
Leaf SpotUncommon

By symptom

Plant problems by symptom

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Growing it

Propagation: cuttings, seed, suckers
When to plant: spring, autumn
Overwintering: No special winter care is needed as they are fully hardy, but ensure they are well watered before the ground freezes.
In containers: Not suitable for containers due to their massive size and aggressive root systems.

Hardwood cuttings

1. Take 30 cm cuttings in late winter.
2. Insert into moist soil.
3. Keep protected until spring growth begins.

Plant these in large open spaces away from infrastructure to accommodate their expansive root systems.

Grows well with

Willow · They share similar moisture requirements and thrive in riparian settings.
Dogwood · They provide a nice understory layer that tolerates the light shade cast by poplars.

Similar species

Aspen · They are closely related and share similar foliage characteristics.
Cottonwood · They are a type of poplar known for their massive size and cottony seeds.

Science

Family: Salicaceae
Genus: Populus
Order: Malpighiales
Class: Magnoliopsida
Native range: Northern Hemisphere temperate and boreal regions.
Conservation: Most species are common, but some regional varieties are protected due to habitat loss.

They thrive in moist, riparian habitats where they pioneer disturbed sites with high light availability.

Value to wildlife: larval host plant, nesting site
Pollinators: bees, butterflies
Uses: ornamental shade tree, windbreak, timber production, soil stabilization

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 2/9
Soil reaction: 6/9
Light: 8/9
Moisture: 7/9
Nutrients: 6/9
Temperature: 5/9

Taxonomy resolved against GBIF.

Questions people ask

Why does my tree shed white fluff?: That is the seed dispersal mechanism of female poplars, which use cottony tufts to travel on the wind.
Can I plant this near my house?: No, their aggressive root systems can easily invade sewer lines and crack foundations.

Where the name comes from

The name Populus is the ancient Latin name for the tree, while the common name poplar comes from the same root.

Good to know

Poplars are dioecious, meaning male and female flowers grow on separate trees.
The wood is lightweight and often used for making matches and crates.
They are among the fastest growing trees in temperate regions.
Their root systems are very aggressive and can damage underground pipes.

Keep your cottonwood growing

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This guide was generated with AI on September 26, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.