When an unusually large swelling at the graft union appears, it is certain that the plant needs protection such as I have described. Such swellings result from a too-rapid multiplication of cells, a condition which leaves the union weak and susceptible to injury. Although a union is never entirely safe, even after many seasons of growth, each year adds to the safety factor by the development of rough, cork-like bark. I suggest the use of a woolen guard for several winters, by which time this outer bark should be able to do its protective work alone.
A successful but rather expensive method of winter protection, both to the graft itself and its union with its host, is to enclose the entire tree with a box-like structure consisting of four corrugated aluminum roofing sheets set up on their ends and countersunk into the ground about six inches. The purpose of countersinking these below the ground surface is two-fold: it stiffens and braces the structure and prevents the intrusion of mice and other rodents, which may also appreciate both the shelter and possible food supply contained therein. By fastening these sheets together with a stout wire you can depend on the structure to stand up against wind and snow pressures. Fill the entire inside with forest leaves, oak leaves preferred, as their insulating quality is the best and they are slow to rot and ferment.
When working with semi-hardy plants in a cold climate, avoid fertilizing and cultivating the ground after the first of August. Doing so stimulates late growth and such growth is very likely to be badly injured during the winter months. If fertilizer is used, it should be early in the spring, as soon as the ground is free from frost. Trees which persist in growing late into the fall are more subject to winter injury. Protective measures to avoid their doing so by inducing an earlier dormancy, include keeping the soil around them dry and exposing, somewhat, the roots near the trunk of each tree.
My last word of advice in raising what might be termed semi-hardy trees, is to grow them in sod, the ordinary quack grass, June grass, bluegrass or other natural grass sods which can be found on your planting site. Although this will probably hold back your tree development for a few years, until the roots are thoroughly established in the deeper soil beneath the sod roots, it is surprising how many species of trees will thrive in sod and perish on open cultivated ground. I can give no better example of this than relating a circumstance which bears this out in a most convincing way. In 1941 I purchased about 250 filbert seedlings from Samuel Graham of Ithaca, New York. These were planted out on a field site and practically all of the plants made good growth the first year. They were thoroughly cultivated. The next year a second batch of plants of a like amount were purchased from the same man and of the same kind of seedlings. Mr. Graham told me that these were seedling trees from Jones hybrid seeds which he had growing in his orchard. These plants were put on heavy sod ground; all plants were protected by screens, but the plants on the sod ground were subject to a very wet season and it was necessary to build up the soil around some of the plants in order to save them from being drowned out. Today about 45 plants are living on the sod culture and two or three barely alive exist in the open field culture. Although the plants remaining alive on the sod culture plot are almost pure filbert strain they are therefore very subject to the common hazel blight. Some have grown into bushes 10 feet high which later were hit by blight and have been reduced to small bushes. Others are producing good filbert-type nuts and are somewhat blight resistant, but the main fact to remember is that about 1/4 of the plants on sod culture lived, whereas not over 2% are alive of the open field culture plants. The distance between these plantings is approximately 1/8 of a mile. In addition to being placed in sod these filberts which have survived are sheltered by rows of evergreen trees both on the south and on the north side which may be construed as of some assistance but is not altogether the reason for the tremendous difference between the winter protection value of sod and open field culture. This is not the only example that I could cite but is one of the most outstanding ones which has come to my attention. Sod culture is now being recommended to fruit orchardists in this part of the country and in my own experience, I can highly recommend it for apples, plums, pears, mulberries and nut trees.
Chapter 15
TREE STORAGE
If it is necessary to store trees through the winter months, one of several procedures may be followed. If the trees are quite small, their tops may be dipped in melted paraffin or beeswax, not hot enough to injure the buds. If the trees are too large for this to be practical, wax may be painted on with a brush. Roots should be protected by heeling them in dirt.
An unheated cellar with a dirt floor is a very satisfactory place for storing trees. Select a corner of the cellar far from any source of heat or temperature change. Place the trees so that the roots are pointing toward the basement wall. Cover the roots to a depth of six inches with either sand or sandy loam, packing the soil firmly to eliminate air pockets. Lastly, cover the trees completely with burlap sacks. Once every two weeks, the earth around the roots should be watered. Trees maintained in this way are conveniently ready to plant when the ground thaws out in the spring.
Another and better method of storing trees is to plant them outside in a trench, preferably on the north side of a building, having first waxed them as described above. One side of the trench should slope so that the trees will lie in an oblique position with their branches touching the ground. The roots of these trees should be covered with dirt, then more trees set alongside them, until all have been planted and the earth made firm about their roots. Trees will usually suffer no damage during such winter storage if their roots have been properly packed in sand or sandy loam. Six or more cans, each containing a little poisoned grain, should be set among the branches. If these cans are laid on their sides, rodents will have easier access to the poison. The branches of the trees should then be well covered with straw or hay, with heavy boards laid on top to keep it from blowing away. If trees are received for planting after the ground has frozen, all that is necessary is to build a log fire on the side where they are to be heeled in. This will thaw out the soil enough so that a trench can be made to accommodate them.