Walnut Growing in Oregon — Walnut Cultivation through Pollination

WALNUT CULTIVATION

While the walnut is the hardiest of trees and in many cases has borne heavily in Oregon without cultivation, experience has proved that, like fruit trees, cultivation up to the tenth or twelfth years increases the growth, the yield and the quality of the product.

After full maturity no further cultivation is necessary, the tree taking care of itself with the independence of any forest tree.

With a young grove it is best to plow between the rows after the rains cease in the spring, and then stir the ground occasionally all through the summer with the harrow or disk; this holds the moisture.

When some trees seem backward a trench should be dug some two feet or so away, and a couple of feet deep, filled with fertilizer and closed over.

This will encourage hardier and more rapid growth.

Lime can also be used with good effect, it being customary in England to haul wagon loads to the walnut lands.

Continually hoeing and digging constitute the best treatment, as one tree on the Prince place, a Mayette, has proved.

It was given daily cultivation, by way of experiment, and more than doubled the size and yield of other trees of the same age not so treated.

PRUNING WALNUTS

Walnuts require very little pruning.

However, to do well they must have plenty of light and air, and there must be room under the trees to cultivate.

To this end, keep all lateral growths removed the first two years, pushing the strong terminal growth.

Young trees so treated often make five or six feet in that time.

They must be staked and tied with a broad strip of cloth.

Cross the cloth between the stake and the twig so as not to bruise the tender wood.

As the limbs begin to grow take out an occasional one to prevent the tree becoming too thick.

When large limbs are removed, cut on the slant, carefully waxing to prevent decay.

Heading-in is often beneficial when the tree does not seem to be fruitful.

Train the trees upward as much as possible.

In Roumania and some of the eastern countries of Europe, some of the walnut trees have such an enormous spread that a flock of five hundred sheep can lie in comfort beneath the shade of one tree and have ample room.

If this vine-like tendency to spread can be obviated by intelligently training the trees upward, and its productiveness maintained or increased, the walnut grower of Oregon will have accomplished much in the conservation of our resources.

At present we can make a tree that will produce 500 pounds of walnuts in 25 to 30 years.

With 12 trees to the acre, will give 6000 pounds of nuts; two and one-half times that of wheat at 40 bushels per acre, and they will not require the expensive refrigerator cars and rapid transit of perishable fruits.

TRAINING THE TREES

It will only be necessary to train the limbs in seven or eight feet all round to be able to double the number of trees to the acre.

Then train the trees skyward and increase the number of nut-bearing boughs, and the yield will be increased accordingly.

If the nuts on the higher branches fill as well as on the lower, the tree can not be made to grow too high, because we have no violent storms to throw down the trees, and the nuts are self-gathering.

These and many other valuable and interesting problems in the industry are to be worked out.

According to Prof. Lewis, who is good authority, a later and better method is to cut the young tree back to 4 feet and make it throw out three or four laterals.

When these laterals are fully grown, bind them up in a bundle one or two feet diameter with soft strands of rope.

In the dormant season cut these laterals back to about two feet.

This will multiply the branches.

Cut back the new growths again the next year, and so on; this will greatly increase the nut-bearing boughs and will train the tree upward.

This seems to be the most sensible method of pruning yet proposed.

NO DISEASES INJURE OREGON WALNUTS

The soft, moist atmosphere of western Oregon, so favorable to the English walnut, seems wholly unfavorable to pests that destroy the crop in other climates.

A crop has never been lost or materially injured in Oregon through these sources; in fact, so free are the Oregon trees of such enemies that little thought or attention has been given to this phase of the subject.

In a few localities where caterpillars have attacked the foliage they have been quickly eradicated by an arsenic spray.

Fumigating will kill insect life.

A bacterial disease that has made its appearance in California has not been seen in this state.

Winter spray of lime and sulphur will kill moss and lichens, which are about the only parasites that attempt to fasten on Oregon walnut trees.

[Illustration: _Old Walnut Trees Planted About 1850 Near McMinnville, on the Yamhill River_] [Illustration: POLLINATION The Walnut] POLLINATION

Every fruit and nut grower should know the simple theory of pollination.

When a tree appears thrifty but fails to produce, nine times in ten the trouble is with the pollination.

The walnut is bi-sexual and self-fertile; the staminate catkins appear first, at the end of the year's growth (see Fig. 1), and the female blossoms, or pistillates, from one to three weeks later at the end of the new growth (see Fig. 2).

Thus the staminate catkins sometimes fall before the pistillates form, and naturally there is no pollination and no crop.

This should not discourage the grower or cause him to uproot his trees.

Often by waiting a few seasons--if the tree is of the correct variety--the trouble may right itself.

Many growers have gotten a crop from single trees where there was trouble with the pollination by artificially fertilizing, that is, shaking the pollen from fertile trees, even black walnut, over the barren pistillates.

Birds, insects, and the breezes carry pollen from one tree to another.

Therefore, if nuts for seed are desired, keep each grove of pure strain separate that there may be no deterioration owing to cross-fertilization.

But the mixed orchard may bear best.

Some varieties of walnut trees--notably the Los Angeles--are suitable only for shade in Oregon and should not be planted with any other thought in mind.

The staminate blossoms of this variety appear six weeks ahead of the pistillates and, there being no pollination, naturally there are no nuts.

[Illustration: _Best in the World, Oregon Walnuts_] [Illustration: _Drying the Nuts_]