Sunday, September 2, 2012

The golden weeping willow

Species name: Salix alba var. vitellina

Common name: golden weeping willow

Location: Ontario

This variety of the white willow is native to Europe, along with the species from which it is derived (Salix alba) and all other varieties with that species name. It is incredibly cold hardy for this area of North America which helps with its attractiveness as an ornamental tree species. The "golden" part of the name comes from the colour of the twigs when young; they're a bright golden yellow which is unusual for willow trees. Unfortunately, like the true weeping willow Salix babylonica from China, this tree is truly a pest when it comes to the roots growing where they don't belong. These species of willow are excellent at searching out water during times of drought, and the roots are strong enough to crack through concrete sewers and completely clog up the inside of the sewer with root growth. They will do the same to your house with your plumbing, and they don't care if they're growing in the fresh water pipes or the sewer pipes; one would be worse than the other for smell once it started backing up in your back yard! I would exert extreme caution if you're thinking of planting one of these in your back yard, and would suggest you seriously think about removing it if you already have one. Plus, they're non-native anyway!

Willows have a long history of being used as a medicinal tree, even back to the times of the ancient Egyptians. Even Hippocrates advocated its use in a tincture to ease fever and pain associated with headache and illness. To make a willow tincture, you take the bark, boil it to release the juices, then mash it up into ethanol (purified alcohol) to make a very thick liquid. Strain the liquid to remove any chunky pieces, and the resulting mixture is consumed. As you can probably imagine, the resulting drunkenness would probably do quite well in removing headache pain all on its own, but all of these herbalists of various ancient times were all onto something; salicin, the chemical derived from willow bark, is incredibly effective against general aches and pains and fever. Henri Leroux was the first to crystallize this chemical, then Raffaele Piria isolated it in its pure form. We now know it as salicylic acid (named after the genus name for willow, Salix) and it can be found as the main medicinal ingredient in aspirin. If we look back in history at all of the plants that were used to treat various medical conditions, most of them are only somewhat effective via the placebo effect: you truly believe you're taking something that will help you, so it does (at least temporarily). This is one of those few exceptions of plants that truly do have very strong medicinal values, and are still being used today.

The bark itself also has other uses aside from medicinal ones; it has been used for centuries as a dye during the leather tanning process. The wood, when burned under low oxygen conditions, results in a specific type of charcoal that was important in the manufacture of gunpowder (although this use has all but disappeared with advances in gunpowder technology). The wood has also been used as lumber, but it is very susceptible to decay so is not used often.