Female Ginkgo Trees

About Ginkgoes

• A native of China, the Ginkgo biloba will grow throughout most of the United States. The trees are popular because they're resistant to pollution and damage from pests and storms, according to the University of Florida IFAS Extension. The slow growers typically reach heights of 50 to 75 feet. They also have irregular shapes and spreads of 50 to 60 feet -- with the females growing wider than the males. In the fall, the fan-shaped leaves turn bright yellow but don't stay on the branches long.
  
  

Reasons for Planting

• Ginkgoes are a hearty street tree planted in spots with enough overhead space for their big crowns. They're also tough, surviving assaults such as road salt, pests and smog; some even lived through the atomic bomb dropped on Hiroshima, reports "The Huffington Post." The trees also can handle temperature fluctuations of cities in the eastern United States, and their roots don't break up sidewalks. Many were planted in Washington, DC, decades ago -- before scientists could differentiate female saplings from males.
  
  

Stinky Seeds

• The seeds appear as yellow, wrinkled grapes in autumn. When they fall, they're filled with butyric acid -- which is found in rancid butter, says "The Washington Post." The fleshy covering attracts carnivorous mammals in Asia, likely because it smells like carrion, according to the Arnold Arboretum of Harvard University. These animals -- which also have included birds and dinosaurs -- help disperse the plants. Another benefit is that seeds cleared of their coverings germinate better.
  
  

Combating the Smell

• In the District of Columbia, the Urban Forestry Administration sprays female ginkgoes with a pesticide in the spring to stop fruit development, according to the District Department of Transportation. Alternatively, residents may have the city remove the trees and replaced them with a different species. The district once unsuccessfully tried to block fruit production by injecting more than 1,000 ginkgoes with a chemical, according to "The Washington Post." Municipalities such as Iowa City cut down the trees, while others such as Lexington, Ky., have banned female ginkgoes.