The Practical Garden-Book · C. E. Hunn and L. H. Bailey
DAHLIA. The Dahlia is an old favorite which, on account of its formal flowers, has been in disfavor for a few years, although it has always held a place in the rural districts. Now, however, with the advent of the cactus and semi-cactus types (or loose-flowered forms), and the improvement of the singles, it again has taken a front rank among late summer flowers, coming in just in advance of the Chrysanthemum.
The single varieties may be grown from seed, but the double sorts should be grown from cuttings of young stems or from division of the roots. If cuttings are to be made, it will be necessary to start the roots early either in a hotbed or house. When the growth has reached 4 or 5 inches, they may be cut from the plant and rooted in sand. Care should be taken to cut just below the joint, as a cutting made between two joints will not form tubers. The most rapid method of propagation of named varieties is to grow from cuttings in this way. In growing the plants from roots, the best plan is to place the whole root in gentle heat, covering slightly. When the young growth has started, the roots may be taken up, divided, and planted out 3 to 4 feet apart. This plan will ensure a plant from each piece of root, whereas if the roots are divided while dormant, there is danger of not having a bud at the end of each piece, in which case no growth will start.
The Dahlia flourishes best in a deep, rich, moist soil, although very good results can be had on sandy soil, provided plant-food and moisture are furnished. Clay should be avoided. If the plants are to be grown without stakes, the center of each plant should be pinched out after making two or three joints. By doing this the lateral branches will start near the ground and be stiff enough to withstand the winds. In most home gardens the plants are allowed to reach their full height, and are tied to stakes if necessary. Dahlias are very susceptible to frost. The tall kinds reach a height of 5-8 feet.
After the first frost, lift the roots, let them dry in the sun, shake off the dirt, trim off tops and broken parts, and store them in a cellar as you would potatoes. Cannas may be stored in the same place.
DAISY. The perennial English Daisy, or Bellis perennis, is a prime favorite as an edging plant. The cheerful little flowers show early in the spring, and with a little care bloom continuously through a long season. They should be given well enriched, moist soil, and be mulched through hot weather. The usual method of propagation is by division of the crowns, made in cool weather. They may also be grown from seed, but the chances are that many inferior flowers will be produced. Set the plants 3 or 4 inches apart. Height 3 to 5 inches. The colors are white, pink and red. Hardy if mulched in winter, but best results are obtained if plants are renewed frequently.
Many other plants are called Daisy, particularly the wild Asters, the Ox-eye Daisy or Whiteweed, and the Paris Daisy (Chrysanthemum frutescens).
DAMPING OFF is the rotting off of cuttings or young plants near the surface of the soil. It is the work of fungi; but these fungi are injurious because they find conditions congenial to their rapid growth. Prevention is worth more than cure. See that the soil is wet clear through, not wet on top and dry beneath. Keep it as dry as possible on the surface. Avoid soggy soils. On peaty soils, sprinkle sand or coal ashes to keep the top dry. Give the plants free circulation of air. Give them abundance of room. If Damping Off threatens, transplant.
DANDELION. This common weed would hardly be recognized if seen under cultivation in the vegetable garden. The plants attain a large size and the leaves are much more tender. The seed may be selected from the best field-growing plants, but it is better to buy the French seed of the seedsmen.
Sow in spring in well manured soil, either in drills or in hills 1 foot apart. A cutting of leaves may be had in September or October, and some of the stools may stand until spring. The delicacy of the leaves may be improved by blanching them, either by the use of boards or earth. One trade packet of seed will supply a large number of plants. The whole plant is destroyed when the crop of leaves is taken.
DATURA. BRUGMANSIA. Large-growing annuals with large, trumpet-shaped flowers. The coloring of some of the flowers is very attractive, but the odor of the plant is unpleasant. Plants should be set 4 feet apart. They grow 3-4 feet high, bear large leaves, and therefore make good low screens. Frost kills them. Sow seed where plants are to grow; or, better, start them in the house three or four weeks before the weather is fit for planting outside. Some of the Daturas are weeds. The great spiny seed pods are interesting.
DELPHINIUM. See Larkspur.
DEWBERRY. The Dewberry may be called an early trailing blackberry. The culture of this, as of the blackberry, is very simple; but, unlike the latter, some support should be given to the canes, as they are very slender and rank growers. A wire trellis or large-meshed fence-wire answers admirably; or (and this is the better general method) they may be tied to stakes. The fruits are large and showy, which, combined with their earliness, makes them desirable; but they are usually deficient in flavor. The Lucretia is the leading variety in cultivation.
Lay the canes on the ground in winter. In the spring tie all the canes from each plant to a stake. After fruiting, cut the old canes and burn them (as for blackberries). In the meantime, the young canes (for next year's fruiting) are growing. These may be tied up as they grow, to be out of the way of the cultivator. Dewberries are one to two weeks earlier than blackberries.
DIANTHUS, or PINK. Under this head are included Chinese Pinks, Sweet William, Picotee, Carnation (which see), and the perennial or Grass Pinks. All of them are general favorites.
The Chinese Pinks (Dianthus Chinensis, or Heddewigii) are now very popular. They are biennials, but flower the first year from seed, and are treated as hardy annuals. They have a wide range of color and markings. Some of them are as double as a rose, and are edged, splashed or lined with other colors. The single ones are very brilliant and are profuse bloomers. Sow seeds where plants are to stand, or if early bloom is desired, start in the house. Set the plants 6-10 in. apart. They grow 8-15 in. high. They bloom until after frost. Of easiest culture in any good soil, and should be even more popular. The petals are often quite deeply and oddly cut.
The Sweet William is an old-fashioned perennial, having flowers of many combinations of color, growing for several years when once planted, but being the better for renewal every two years. Raising new stock from seeds is usually better than dividing old plants. Of late years, the Sweet William has been much improved.
The perennial garden or Grass Pinks are low-growing, with highly perfumed flowers. They are very useful for permanent edgings, although the grass is likely to run them out unless a clean strip is kept on either side. Divide the old plants when the edging begins to fail; or raise new plants from seed. Seedlings usually do not bloom much the first year. Usually perfectly hardy.
DIBBERS are hand tools used for making holes in which to set plants or to drop seeds. They are better than a hoe or a spade for most transplanting. For small plants, as cabbages and tomatoes, a cylindrical Dibber is generally used. (See the lower one in the cut.) It can be made from an old spade handle or any hardwood stick. When broad holes are wanted, the triangular iron Dibber (sold by dealers) is excellent. It is particularly useful in hard soils.
DICENTRA includes the Bleeding Heart; also the native little Dutchman's Breeches and Squirrel Corn, and a few other species. All are hardy perennials of the easiest culture, blooming in spring. In common with all perennial herbs, they are benefited by a winter mulch of leaves or litter. Propagated by dividing the clumps.
DICTAMNUS. FRAXINELLA or GAS PLANT. An old border plant (perennial herb) with white or pale red flowers. The leaves of the plant emit a strong odor when rubbed, likened to that of the lemon verbena. It has been advertised as the Gas Plant from the fact that the plant exudes an oily matter that may be ignited, especially in warm, dry weather. Propagated by seeds, which should be sown as soon as ripe. The plant blooms the third year, and improves with age. Set plants 3 feet apart. Height 2 to 3 feet.
DILL. An annual aromatic herb that will seed itself if seeds are left to ripen, and an abundance of plants may always be had. The culture is of the easiest. The seeds are often used to flavor pickles.
DISEASES. Diseases of plants may be caused by some physiological disturbance to the plant system, or by the incursions of some parasitic organism, as insects or fungi. The work of insects, however, is ordinarily not classed with plant Diseases (see Insects). Of Diseases which are caused by plant parasites or by physiological disturbances, there are two general groups:
(1) Parasitic fungous Diseases, such as the apple-scab, black-rot and mildew of the grape, leaf-blight of the plum and pear, black-knot, and the like. These Diseases are characterized by definite spots, discolorations or excrescences, which are more or less scattered over the surface of the leaf, fruit or branch. As a rule, the leaves and fruits which are attacked have a tendency to drop from the tree. The general treatment for these Diseases is to spray with some fungicidal mixture, like the Bordeaux mixture or the ammoniacal carbonate of copper. The treatment is useful in proportion as it is applied early and thoroughly. After the fungus once gets into the tissues of the host-plant, it is difficult, if not impossible, to kill it. If, however, the fungicide is upon the plant before the fungus is, the parasite may not be able to obtain a foothold. Even after it does obtain a foothold, it is probable, however, that the spray will check its spread by preventing the development of its external parts.
(2) The physiological and bacterial Diseases, or those which are termed constitutional troubles. In these cases there are rarely any definite spots, as in the attacks of parasitic fungi, but the entire leaf, or even the entire plant, or a large part of it, shows a general weakening and Disease, as if there were some cutting off of the accustomed source of nourishment. Such Diseases are very likely to be seen in a general yellowing and death of the leaf, in the dying of the leaf along the main veins and around the edges, showing that the difficulty is one which affects the entire leaf, and not any particular part of it. In general, there is a tendency for the foliage in plants so attacked to wither up and hang on the tree for a time. The peach-yellows and pear blight are Diseases of this kind. There are no specific treatments for troubles of this sort. They must be approached by what physicians call prophylaxis--that is, by methods of sanitation and prevention. The diseased plants or parts are cut away and burned. All those conditions which seem to favor the development of the Disease are removed. Varieties which are particularly susceptible are discarded. Careful management in matters of this sort is often much more important than any attempt at specific treatment.
DOLICHOS. Mentioned under Hyacinth Bean.
DRACAENAS of the conservatories (properly mostly CORDYLINES) are sometimes used as house plants. Protect from direct sunlight, keep an even and fairly high temperature, water freely when they are growing. When the plants begin to fail, return them to the florist for recuperation, where they may have equable conditions. They are handsome long-leaved foliage plants, excellent for jardinieres.
DRAINAGE serves two purposes: first, to carry superfluous water from the land; second, to lower the water-table or hard-pan, and to make the soil loose and friable above. Nearly all hard clay lands are much benefited by draining, even though they are not too wet. The region of free or standing water is lowered and air is admitted into the soil, rendering it fine and mellow. For carrying off mere surface water, surface or open ditches are sufficient; but if the soil is to be ameliorated, the drain must be beneath the surface. The best underdrains are those which use hollow or cylindrical tiles, but very good results may be had by making drains from stones. In regions where there are many flat stones, a very good conduit may be laid with them, but they are likely to get out of order. If there is considerable fall to the ditch, the bottom may be filled for the space of 10 inches or a foot with common stones rolled in, and the water will find its way between them. If the stones are even deeper than this, the results will be better; and such ditches also provide place for disposing of superfluous stones.
The deeper the ditch the further it will draw on either side. It should always be deep enough to be protected from freezing, particularly if tiles are used. Three feet should be the least depth, and 3-1/2 feet is a good average depth. Drains as deep as this need not be placed oftener than 2 to 3 rods apart, unless, in garden conditions, it is desired to very thoroughly ameliorate a heavy clay soil, in which case they may be placed every 20 feet. The better the fall the quicker the drain will act and the more permanent it will be, as it will tend to clean itself and not fill up with silt. It is important that the outlet be entirely free, and it should be protected with stones or mason work. The roots of some trees, particularly of willows and elms, are attracted by tile drains, and often fill up the pipes. When the drain goes near such trees, therefore, it is well to cement the joints. In general practice, however, the joints should not be cemented, because a large part of the drainage water enters at those places. In laying the tiles, it is well to cover the joints with inverted sod, tarred paper, wisps of straw, stones or other material. This prevents the fresh earth from falling in between the joints, and by the time the material is decayed the earth will have become so thoroughly set that no further trouble will result. Although under-drains take off superfluous water, nevertheless an under-drained soil will hold more moisture than one which is not drained, particularly in the case of clay lands with high subsoils. This is because fine, mallow soils are able to hold more moisture than very loose and open or very dense and compact ones. A well constructed underdrain should last indefinitely.
DUTCHMAN'S PIPE. See Aristolochia.
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