Rough Draft 1.0 10/5/2020
Let’s get one thing straight right off the bat, growing walnut trees is a multi-generational endeavor if you’re focus is on growing walnut trees for lumber. It can take 50 or more years to grow a harvestable tree. One in a hundred or so may yield veneer quality lumber which can be quite valuable. There are, however other benefits such as providing habitat, food source, and of course, the beauty and environmental benefits. The botanical genus for walnut trees is Juglans “Jupiter’s nut” and they belong to the Juglandaceae family. The walnut fruit is a drupe – “a stone fruit in which an outer fleshy skin surrounds a hardened shell protecting a seed inside.” Walnut trees are monoecious, meaning a single tree self-pollinates as it contains both male (catkin) and female (pistillate) flowers. Nut production is highest when different cultivars are planted in groups.
Walnut Tree Species
WARNING – Walnut trees produce a toxin called juglone which will keep vegetation from growing well around the base of the tree.
Eleven Species that can be grown in North American Landscapes
Andean Walnut Juglans neotropica
Arizona Black Walnut Juglans major
Black Walnut Juglans nigra
Butternut Juglans cenerea
Brazilian Walnut Juglans Australis
California Black Walnut Juglans californica
English Walnut Juglans regia
Northern California Black Walnut Juglans hindsii
Japanese Walnut Juglans ailantifolia
Manchurian Walnut Juglans mandshurica
Little Walnut Juglans microcarpa
Basic Growing Tips
- Layout a plan and planting area and spacing.
- Decide on which types of walnut trees grow best in your location and source a nursery that can provide you with trees. Alternatively, you can source seeds and sprout them (INTERNAL LINK TO WALNUT SPROUTING GUIDE ARTICLE)
- Plant trees in desired location.
- Protect saplings from deer and keep grove mowed.
- At year 3 or 4 start pruning trees to encourage a straight trunk.
- Continue limbing trees up (if growing for lumber) so there is a clear trunk at least 16’ tall.