Walnuts

1. Q. My tree has produced English (Persian, Carpathian) walnuts for years but the kernel is always dark when I shell the nuts. What am I doing wrong?

A. English walnuts should be picked, hulled and dried as soon as they are physiologically mature. A delay in harvest and drying will result in dark colored kernels or development of mold which will destroy the kernel.

When English walnut trees receive enough rainfall or irrigation water during nut development, nut hulls begin to burst uniformly all over the tree. These are ideal conditions for harvesting. However, when trees do not receive adequate moisture during the period of nut development, hulls do not burst uniformly, if at all, and maturity can be determined by periodically inspecting the tissue between the kernel and inner lining of the shell of sample nuts. Walnuts are ready for harvest when this tissue turns brown. Also, when mature, the hull becomes loose around the nut, under conditions of inadequate moisture for the tree, even though the hull does not burst.

Begin checking for brown tissue between kernel and shell and loose hulls around English walnuts during the last two weeks of August through September. When it is determined that nuts are mature, collect, hull, and air dry them for two weeks before you store, eat or sell them.

2. Q: I have a black walnut, grafted onto a maple root system. Though young (5 years, I guess), it is well established. Was planted last March. Growth this year was 10-12". Top of central truck is just under 6'. Avg. diameter is 1.5", with larger 3" diameter base just above soil line.

Problem: Most limbs are concentrated near the top, and are relatively short. There are 2 major limbs about half-way up. These bear 80% of the foliage. They are located on 1 side of the tree, with about a 70 degree angle between them. As a result, the other side of the tree is noticably barren of limbs and foliage. Now that the tree is firmly established and growing well, I will prune these two limbs back in January. But how do I force new limb growth on the other side of the tree in order to even it out? Is there some scoring or cutting I can perform that will encourage this? Perhaps some sort of poultice of moss and water/fertilizer? Anything that would encourage the tree to sprout new limbs on the barren side?

A: Are you sure the black walnut is grafted onto a maple root system? If so, it is the only one in the world! Plants and/or trees have to be in the same genus in order to be graft compatible.

However, this has no bearing on the pruning question. The best way to get limbs to grow on the barren side is to do nothing at all. Scoring and special fertilizer will not help. Often trees are this way because of the prevailing wind. We have found that if you leave the small shoots on the lower trunk, but keep them pinched back that it will add a lot of stability and growth to the tree. Also if you want a shoot to grow a lot, you cut it a lot, but if you want it to slow down you just tip prune it, ie. about one inch of growth.

So in your case I would totally remove one of the larger shoots all the way back to the main trunk and just tip prune the other one. This should force out numerous shoots all over the tree. Over time the tree should fill in nicely.

Q: I recently moved to a home that has two black walnut trees. I want to collect the nuts, but I don't have the slightest idea how, do I leave on the green husk or take it off? do I have to store them for a time?

A: Wait until the black walnuts drop from the tree this fall. The green husk will have turned black and will need to be removed from the nuts which is no easy task. Then let them dry in a dry cool area for an additional two to three weeks. Once they are dry they can be shelled or placed in refrigeration in order to maintain their quality. It is best to go ahead and shell them prior to storing as they are less bulky. Place the kernels in a plastic bag of some sort and then place them in the freezer. Use and enjoy at your leisure.



| Parson's Archive Home | Aggie Horticulture |