One hazel plant when left free to its own devices may increase in this way rapidly enough to drive cows out of a pasture lot. I have trimmed off stoloniferous roots experimentally from a number of hazel plants, for the purpose of throwing all of the strength into the original stocks, hoping, thereby, to prolong their lives. This, however, appears not to be effective, as the stocks died at their appointed time.
Like many other wild plants, not yet subjected to processes of cultivation, the common American hazel does not respond very readily to cultivation, and too much attention on the part of the horticulturist leads it into confusion.
Some years ago I expended about six weeks in making a study of fruiting hazels and examined many thousands of bushes in Rhode Island, Connecticut and eastern New York state, including Long Island.
In the regions visited, the native hazels are so abundant as to be considered a pest. Out of all the bushes examined, I saved but three for purposes of propagation. The best one of these for size, quality and thinness of shell, I have named the Merribrooke, and young plants of this variety will be sent to any member of the Association who wishes to cultivate them. Bushes of this particular wild variety have had a reputation among the boys of the locality for more than a hundred years, according to legends of the neighborhood. I have recently budded specimens of this variety upon stocks of the Byzantine hazel, in the hope of prolonging the life of an individual plant beyond its normal seven or eight years.
The other American hazel, variously known as the beaked hazel, tailed hazel or horned hazel, was named Corylus cornuta by Marshall (Arbustrum Americanum 37, 1785). Consequently, that is the name by which it should be known instead of the name Corylus rostrata which was bestowed subsequently. This hazel has a much more northern range than the common American hazel and I have seen it in Labrador and in Ontario nearly to Hudson's Bay. On the Pacific coast it is said to reach a height of thirty feet. Although spreading by stoloniferous roots like the common American hazel, these roots are shorter, and it does not extend rapidly enough to dominate the situation when growing in competition with the common hazel.
The nuts, while very good, and sometimes of large size with comparatively thin shell, lack quality, a very important element in any nut. It is probable that this tailed hazel will be valuable for adding hardiness to hybrids with the European and Asiatic hazels, when the time comes for horticulturists of Canada to make fortunes from their hazel orchards.
In Europe and Asia and in the northern parts of Africa several species of hazels are extremely important commercially, sometimes furnishing the chief source of income for large districts, very much as wheat or corn make special crops over large areas in this country.
These foreign hazels have not been raised successfully in our country, excepting very recently on the northwest coast. The reason for failure depends almost wholly upon the presence of a blight, Cryptosporella anomala, which belongs to our native hazels. In the course of evolution, host and parasite have come to be peers of each other, and consequently this blight does not menace our native hazels very seriously. Introduced species, with the exception, perhaps, of the Byzantine hazel, appear to carry a protoplasm which has not learned to resist the attacks of the blight. All organic warfare is fundamentally enzymic in its nature, and it is possible that through process of natural selection some of the foreign hazels would eventually become securely established in this country, without aid from the nurseryman.
As a matter of fact, the hazel blight is very easily managed. Not knowing this at first, I allowed almost all of my exotic hazels to become destroyed, and a number of nurserymen told me of having given up the problem as hopeless. Recently I have learned of the ease with which the disease may be controlled, and now feel very comfortable in its presence.
The blight is of slow development and chooses the larger hazel stems for its battleground. All that one notices at first is a depression of the bark extending in the long axis of a large branch. If one observes more closely, he will find spore-bearing pustules occurring as little round elevations upon the depressed part of the bark. The blight proceeds slowly, and I pass about for examination specimens from two hazel limbs. In the smaller one the blight has been two years under way, and in the larger one three years. These patches of blight were allowed to grow experimentally. Meanwhile, I trimmed out all other blight areas of the bark with my jack-knife. This is very readily done. If one will look over his hazel bushes once a year and simply whip out the few slices of bark carrying the blight, it is done so easily and quickly that we now need to have no fear whatsoever for the future of hazel culture in this country.