Black Walnut Questions & Answers
9 Year old genetically superior black walnut in Central Illinois
1. What are genetically superior black walnut trees?
These trees are the result of decades of research by a forest geneticist from a
leading Midwestern university. Originally, scion wood, or bud wood, was collected
from over 400 black walnut trees throughout the Midwest that had superior form.
Through a selection process using form and growth rate as criteria, the geneticist
determined the most superior trees. Over the years, through genetic selection of
successive generations, trees with increased growth rate, vigor and vitality have
been developed while maintaining superior form. The two most famous cultivars patented
by the university are Purdue Number One and Tippecanoe Number One.
2. What are the main differences between the improved seedlings and the grafted trees?
The grafted trees are genetically identical clones of the parent cultivars described
above. The superior seedlings are grown from the nuts of these trees as well as
the original Purdue Number One cultivars. As such, the seedlings will vary somewhat
from their parent trees but will still possess better genetics than common seedlings.
3. Is the genetically superior walnut tree cultivar really that much better than
common seedlings?
The forest geneticist who developed the genetically superior trees estimates
that only a fraction of 1% of common black walnut seedlings will have the same growth
and form characteristics as the genetically superior trees. Even when given the
best care, maybe 10% will produce veneer-quality wood, but only after a period of
50-60 years or more. Results from our planting of superior seedlings show that at
least 60% should make veneer grade with proper care. Except for those damaged by
outside forces (lightning, wind), virtually all of the grafted trees should be veneer
grade if given proper care.
Genetically superior black walnut trees at 8 years in Northern Indiana.
4. How big are the genetically superior black walnut trees for sale?
Grafts range from about 12” to 24” above the root collar, and 1/4” to 1/2” in
diameter at the base. Seedlings are 8” to 18” in height.
5. Will the genetically superior black walnut trees grow in my area and survive?
The natural range of the eastern black walnut tree (Juglans nigra) is from southern
Ontario to Texas and Alabama and from Nebraska to the Atlantic Ocean. However, genetically
superior walnut trees have been planted in Florida, New England, Michigan’s upper
peninsula, Idaho and even on the west coast.
6. What type of root system do they have?
They have a deep tap root system.