Walnut
Juglans regia
Family · Juglandaceae · Harmless
The walnut tree, planted on farms and stream margins across the country and gone feral in many valleys. Almost nothing grows under a walnut, and that is no accident: the roots release a compound that stops competition.
Streams and ditches · Fields and pasture · Oak woods · Town and roadside
Also known asEnglish walnut, Persian walnut
How to tell it
A compound leaf of five to nine large, smooth-edged leaflets, with a strong characteristic smell when crushed. Smooth grey bark when young, cracked with age. A round green fruit that splits and releases the nut inside.
What it is confused with
Tree of heaven
Ailanthus altissima
Both have a large compound leaf and a strong smell. Walnut has five to nine smooth-edged leaflets and a pleasant smell; tree of heaven has twenty or more leaflets with two glandular teeth at the base and smells of rancid butter.
What it is for
The nut, and the green husk that stains hands brown for a week and was a dye and wood varnish. The leaves were an infusion and a home insecticide. The compound it releases is called juglone, and it is why you do not plant a vegetable garden under a walnut.
Traditionally used as food. This is not permission to eat it.
With documented traditional uses. Not a therapeutic indication and not a dose.
Where it occurs
Each square is an area with recorded observations of this plant. The lighter background is the set of areas where any of the entries has been observed, and serves as a reference. Note what this is not: it is not where the plant lives, it is where people record it, so trails and towns always look fuller than the mountains. Data from GBIF.
Sources
Community
No approved contributions for this entry yet.
Nothing appears here without a person reading it first. Contributions do not replace the entry or its warnings: until a botanist confirms, what is written above stands.