Walnuts are fantastic trees that protect their territory by releasing a potent chemical into the surrounding soil. The active principle, juglin or juglon (hence the scientific name, Juglans), prevents many other plants from establishing a roothold there.
The clan includes a number of species; the most important are the native North American black walnut (Juglans nigra), the Arizona walnut (J. major), and the magnificent Persian walnut (J. regia).
The desirability of the latter species isn’t lost on India and Pakistan, which may be gearing up to fight a war over Kashmir, the province in between them that’s been a battle ground (marked by demonstrations, occasional terrorism, and political rhetoric) for decades.
And why is Kashmir in dispute? One reason, historians and horticulturists report, is that it’s a fruitful place where the Persian walnut (among hundreds of tree species and other plants) flourishes on mountain slopes at elevations of 4,000 to 7,000 feet.
It’s said that during the Golden Age on Earth, men lived on acorns — and the gods lived on walnuts. According to Pliny, the Persian walnut was introduced into Italy long before the birth of Christ. The Dutch call it “walnoot,” and the Romans called it “Jupiter’s nut.”
But it’s not just the Persian species that’s noteworthy — walnuts in general are great and noble trees. In England, a single walnut tree was worth up to 600 pounds at a time when one could live well on only a few pounds a week.
Until I read Mrs. Grieve’s book A Modern Herbal, I didn’t realize that the oil yielded by the kernel of the fruit (not the part that’s eaten) is used to polish the wood. Because it doesn’t congeal in cold conditions, the oil is deemed especially valuable as a varnish and for applying gilt to frames and moldings.
The unripe fruit is said to make a great pickle. I do remember seeing jars of pickled walnuts but found them less to my taste than peanuts (which aren’t nuts at all).
Herbalists have also made a gargle for inflamed throats from green walnut husks boiled in honey, but that seems a bit much to me.
Still, if you’re one of those gardeners who’s inclined to declare war on the walnut because it can make such a tough neighbor, think again. In fact, there are more than 100 plants — from violets to yuccas — that will coexist with walnut trees. Drop me an e-mail at my Web site (www.thewildgardener.com) if you want the list.