White Poplar, named so for their white bark (when new) and white leaf undersides, are fast-growing, colonizing deciduous trees. While commonly grown for their ornamental purposes, a very wide range of pests and diseases tend to kill these trees off. These may outcompete some native trees if given enough space and mature male and female trees. These are native to Asia.
Populus alba (White Poplar, Silver Poplar)
Deciduous: yes
Hardiness Zones: 3-8
Height: 15-22 meters (50-75 feet) tall, rarely to 40 meters (130 feet) tall
Diameter: 15-22 meters (50-75 feet) wide, diameter to 2 meters (7 feet) across
Growth Rate: Fast, four year old seedlings may reach 5 meters (16 feet) in height.
Age: Flowering typically begins at 5 to 7 years old.
Root System: shallow, rarely below 1 meter (3 feet) in the soil
Family: Salicaceae
Subspecies: var. bolleana, var. pyramidalis
Tolerates: urban conditions (air pollution)
Problems (major): dieback, cankers, leaf spot, powdery mildew, rust, borers, aphids,
caterpillars, scale
Problems (minor): In certain areas, prolific seeding and colonization outcompetes some
native species.
Poisonous: no known toxins
Soil requirements: prefers consistently moist, well-drained loams (medium soils)
Air requirements: tolerates air pollution
Watering requirement: moderate
Sun requirement: full sun required
Leaves: 3 or 5 lobes, light green above, white (appears as if paint sprayed) on bottom
Flowers: catkins (male red to 10 centimeters (4 inches), female green to 7 centimeters (3
inches)) occur in April before foliage emerges, wind-pollinated
Fruits: Seeds are light-weight and wind-dispersed (typically stay within a 1 mile radius of
the parent plant). The seeds may germinate within 24 hours of encountering favorable
conditions.
Bark: white when new, browns with age
Form: usually oddly rounded, may be columnar or conical
Seeds require stratification: No, germination occurs very rapidly once the seeds mature.
Monoecious or Dioecious: dioecious
Monocot/Dicot: dicot
Notable characteristics:
White Poplar, like other Poplars, Birch, and Aspen, send out suckers to form colonies.
These suckers may grow up to 50 meters (160 feet) away from the parent plant. Suckers may
come up years after the parent plant has past. These will likely thrive once a fire sweeps
through its region, as it quickly respouts. These may hybridize with Bigtooth Aspen,
Quaking Aspen, European Aspen, and Chinese Aspen.
Uses:
These are typically planted for their ornamental value. However, the myriad of ailments,
shallow root system, and prolific colonization make this a questionable street tree at
best.
Sources used:
- http://www.fs.fed.us/database/feis/plants/tree/popspp/all.html
- http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspxtaxonid=286780&isprofile=1&basic=Populus%20alba
- http://plants.usda.gov/core/profile?symbol=poal7
The bark remains white when new young but begins to turn brown with age.
A green-yellow female catkin with seeds. These seeds will readily germinate in lawns and grow rapidly.
Foliage
General form
Red male catkins in March, hundreds may be present at one time on a mature tree.
A young seedling that recently germinated.
All of the images provided were taken by me. They may be used for educational/informational
purposes only, provided that this article/online journal is appropriately cited first.
A Fascinating Green World 