Evergreens
| Standard Cyclopedia of Horticulture |
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Evergreens. In horticulture, evergreens are plants that retain green foliage the year around; they do not shed all their foliage at any one time; in some cases, the individual leaves may remain attached and green for some years, as in many of the Coniferae, but in all evergreens the old leaves shed after a time when they become so overshadowed or crowded as to be no longer functional. The leaves of pines and spruces may persist three to fifteen years. In the popular mind, "evergreen" and "conifer" are synonymous; but some conifers—as the taxodiums and larches—are deciduous. Moreover, in the tropics very many trees aside from conifers are evergreen, as notably the palms. Evergreens may be classified as coniferous and broad- leaved, the latter including such plants as rhododendron, kalmia, mahonia, box and many others. The number of plants that are evergreen in the latitude of New York City is very large. Few persons recognize the wealth of good winter greenery that may be secured by exercising careful choice of material and providing proper conditions and protection for its growth. There are many very low evergreen plants that may contribute much to the winter interest of a yard or garden, in the way of edgings, masses, rosettes, and ground cover. The following lists indicate the materials that are now at the command of the planter. Beyond the latitude of Lake Erie, the dependable evergreens are mostly conifers. At the Central Experimental Farm at Ottawa, those deciduous plants that hold their foliage fairly late in the autumn are mostly too tender for use. A few good plants, however, are, Oregon grape (Mahonia), bearberry (Arctostaphylos Uva-ursi), Pachysandra terminalis, shrub yellow-root (Xanthorrhiza apiifolia), and Quercus imbricaria. The Oregon grape is perhaps the most useful evergreen there for ground-covering. The hardier species of Ligustrum are also fairly satisfactory, but most of the species of this genus leave so much dead wood after winter that in very large masses they are liable to be unsightly. Many attractive conifers are reliable at Ottawa, in the genera Abies, Chamaecyparis, Ginkgo, Juniperus, Picea, Pinus, Pseudotsuga, Taxus, Thuja, Tsuga. The uses of evergreens are discussed in other places in the Cyclopedia, as under Arboriculture, Herbary, Landscape-Gardening, Lawn-Planting, Perennials, Rock-Gardening, Screens, Shrubbery, Topiary Work, Wild-Garden, Windbreaks, Winter-Gardening. For lists of evergreens for California, see pp. 379-381 (Vol. I). L. H. B. Moving large evergreens. Figs. 1452-1457. Large evergreens are moved with a ball of earth because they have no dormant period, but carry their foliage and need moisture at all times of the year. It is essential that the ball of earth contains a sufficient amount of small fibrous feeding roots to support the tree and that the tree be kept well watered for two or more seasons until the tree has spread its roots over sufficient area to gather enough rainfall to sustain the normal growth. The extent of fibers in the ball is increased by transplanting and root-pruning. Root- pruning is less essential with trees having an abundance of fibrous roots than with trees haying only a few large coarse roots in the central portion. Some trees, as white pine, will survive with a comparatively small number of roots, their drought-resistant qualities enabling them to persist with a small supply of moisture. Other evergreens, as Nordmann's fir, have a long carrot-like taproot, and the tree is likely to die if this is cut and the tree given an inadequate quantity of water. Frequent nursery transplanting is, therefore, necessary with this species. Trees are dug by starting a trench at a radius from the tree about 3 feet wider than the ball of earth to be taken. The roots are cut off on the outside of the trench and the soil dissected out from between the roots back to the size of the ball. These roots are bent around against the ball of earth if they are flexible enough to bend. If not sufficiently flexible and tractable, they are cut off. A canvas is made 15 to 24 inches deep, and is made smaller at the bottom by folding over a V and sewing it. This makes it fit a conical ball and, when it is pulled up 3 inches by the cross-lashing at the top, makes it tighter. The canvas has cross-ropes sewed on it with rings at the top and bottom, and on the deeper balls two rows of rings in the middle. The bottom rope is tightened by a wooden lever 20 inches long with four holes, the rope being looped through the holes and the lever thrown over to pull the rope tight. The top rope is then tied and tightened by cross-lashing. To get the ball free from the subsoil, dig under all around and tip the tree slightly. Level off the bottom with a fork. If there are tap-roots, tunnel under and cut them with a saw. Put a platform as far under as possible and tip the tree back. To get the ball in the center of the platform, put a hammock around the ball and pull. Hold the platform in position by crowbars driven in front of it. Lash the ball to the platform, make an incline, drag the platform out of the hole onto a truck or sled. Skids with small wheels set in them about 1 foot apart enable a team to load a ball quickly. With balls 10 to 15 feet feet in diameter and 20 inches deep, jacks and pipe rollers are needed. Trees over 10 feet need to be tipped over to go under wires. If the canvas is put on tight and at the proper taper, and if the ball is cut flat to fit close to the platform and lashed tight to the platform, the tipping can be done without the ball shaking loose. Sometimes a canvas or burlap bottom can be put between the platform and the ball. In unloading, the tree is stood up, team hooked to the platform and the tree dragged off to the ground. The tree may drop 2 feet without injury. The platforms are dragged to the hole and balls less than 4 feet rolled into the hole. Larger balls have the platform dragged into the hole and the platform pulled out holding the tree in position by a hammock. To straighten the tree, tramp the earth solid under it until it stands erect. Take off the canvas, spread out the side roots, pack the earth and anchor as with deciduous trees. Keep the ball moist; examine it once a month or more often by digging or boring into the ball during the first two years. Evergreens moved with a too small ball or with not enough fibers in the ball or with the watering neglected, may grow 3 inches a year for the first two or three years. If properly moved, they will grow 6 inches or more a year— half their normal growth. Deciduous trees may be moved with balls of earth by the above method, and it has proved an aid with difficult species, as beech, oak, liquidambar, tulip. Especially when previously transplanted or root- pruned, the above trees 3½ inches in diameter moved with a ball of earth 4 feet in diameter are very successful, while without a ball many are lost or the growth is much slower. Investigation should be made to see whether this is because of less disturbance of the roots or because there is carried with the roots and soil a mycelium of a fungus which aids the roots to take up plant-food and moisture. The time of year for moving trees is of minor importance. It is overemphasized by purchaser, landscape architects and nurserymen, and results in heavy financial loss to nurserymen in congesting sales and their own planting in the short spring season. It greatly lessens the total amount of planting needed for forest, shelter-belt, landscape, fruit, and other economic purposes. A nurseryman may plant all the year. Evergreens can be taken up with a ball of earth even in May and June. The new growth may curve down. After June 20, the spruces, and after July 10, the pines, are firm enough not to wilt. August-September sales with a ball of earth are just as successful as April. The ground is warm and the roots grow rapidly; the ground can be made moist. Weather in September is less dry than in May and June. Small evergreens up to 2 feet high may be planted in August and September from one part of the nursery to another without balls of earth, if the roots are very carefully dissected out without breaking. There will be more failures if the week following planting is hot and dry. Planting with balls of earth may continue all winter, especially if the ground is mulched to keep out the frost and permit economical digging of the tree and the hole. The frozen ball of earth is an old method, frequently referred to, but is not an aid. If the ball is frozen solid and remains so for one or two months with dry winds, the top may dry out and die as has occurred with red cedar. If the ball is not frozen, sap can come up to take the place of that lost by transpiration. A ball of earth 3 feet in diameter is needed for an evergreen 8 to 10 feet high ; 4½ feet in diameter for an evergreen 15 feet high, except red cedar which can have a ball 3 feet; a ball of earth 12 feet in diameter is needed for a pine 35 feet high. Root - pruning pines, spruce and hemlock, permits moving the following year with a smaller ball than otherwise. In root- pruning, the trench can go three-quarters of the way around or three or four of the larger roots can be left across the trench to keep the tree from blowing over. Root-pruning of red cedars is of less advantage and is rarely practised. In New England and northern New York, the pine, spruce and hemlock, have only a few coarse roots just under the surface and no roots extending 2 feet deep. When moved to better-drained soils on the coastal plain, they develop deeper roots and have ten times as many fibers in a ball 4 feet in diameter. The above evergreens with their shallow root-systems can be taken up with a disc of roots, peat and grass 8 inches deep and 3 to 4 feet wide. This can be set on a wagon and: trees 10 to 15 feet high easily moved. Less roots will be broken or bare if the ball is tied in burlap. The usual cause of failure in this operation is neglect of watering. Hemlocks and probably other trees will be aided by shading for the first two months. Woody evergreens for New England and New York. B - Broad-leaved evergreens. S - Semi-evergreen. P - Protected at Arnold Arboretum, Boston. T - Tender above New York City. Broad-leaved evergreens for Washington and the South. Broad-leaved evergreens hardy at Washington, D.C. The evergreens and half evergreens of foregoing list are also good. Broad-leaved evergreens hardy at Norfolk and South The following list of broad-leaved evergreens hardy at Arnold Arboretum may also be expected to thrive at Washington. A list of broad-leaved evergreens in addition to those recommended for Norfolk, Virginia, for the South Atlantic and Gulf Coast regions and as far inland as Augusta and Montgomery. Those marked "S" thrive only in the warmest sections. F. L. MULFORD. Plants that are evergreen on the middle Great Plains. It must be remembered that on the Great Plains the conditions vary enormously, and that few plants naturally range over the whole area, or are capable of being successfully grown in artificial plantations throughout the whole area. Two special localities are frequently mentioned in the list. Arbor Lodge is the arboretum established by the late J. Sterling Morton at Nebraska City, within a few miles of the Missouri River. The University Arboretum is at Lincoln, Nebraska, on the high prairies 60 miles west of the Missouri River. Trees. Shrubs. Rosettes. Many herbaceous plants have rosettes of green leaves throughout the winter, the following being the more conspicuous on the Great Plains
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References
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963
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