The German iris is one of the most beautiful forms in the flower world and it will flourish in practically any moderately good soil
We must remember that nine-tenths of the plants we grow are exotic—natives of distant parts and climes—coming from various atmospheric conditions, and from all kinds of soil. We bring them into our garden and grow them all under one climatic influence and in the one kind of soil we happen to possess. Certainly we cannot expect uniform success with all of them. You might as well bring into one room unlettered natives of distant climes and expect them all to enter into a general conversation. Even in gardens quite near each other, their permanence varies. I cannot grow, successfully, any of the boltonias, while within a quarter of a mile of me, in a friend's garden, they grow like weeds. Our soil is the same, and one would suppose that the climatic conditions were, still the fact remains. I merely mention this so that any novice finding that he cannot grow some plants as well as others near him, may not feel lonesome in his grief. It is, however, a good plan, when a plant supposedly easy to grow, fails to materialize, to try it in another part of your own garden, and if it does not do well there, discard and forget it—the world is full of good things.
Due to the fact of the perennial's habit of annual recurrence the cultural directions are different from the flowers of but a season's bloom. There are some vital fundamentals that every gardener should know and some short cuts to success that every one may know. Since perennials, then, form the very kernel of the garden these are things of first importance in the growing of flowers and will be here elaborated sufficiently to give the reader an impetus that will carry him at a bound into the inner circle of the garden mysteries.
PREPARING THE BEDS
Do we want a successful flower bed—one that our neighbors will envy—or one in which the plants are struggling to exist? If we want the former—and who does not?—we must give our plants good pasturage. They are as fond of the fat of the land as we are, and, since they gladden our hearts with their radiant blooms, we should treat them fairly. And how? By giving them a good, deep soil for their root-run, not only rich in food, but loose and friable.
Most all virgin soils contain ample plant food, but the deeper part lacks the result of the action of air, sun and frost, and the natural humus of decayed leaves and grasses. The plant food it contains is "uncooked"—that is, not ready for plant assimilation. Therefore, the beds to contain your perennials should be dug at least two feet deep—three is better—and good garden soil, or soil from a corn-field or any hoed crop where the weeds have been kept down, used to supplement all but the top layer one foot in depth. All of this applies to tree and shrub holes also. This top layer of one foot in depth is apt to be in fair condition for immediate use and may be applied in the bottom of the bed, mixed with either fresh or rotted manure. The soil brought in may be mixed with old manure and placed on top.
A word about "old manure" is opportune here. Any manure that has been piled up for a year or more in a weed-infested corner and used on your grounds, especially on your lawn, is the best promoter of exercise I know of, and can keep you busy all summer dislodging the weeds that spring from the seed its bosom protected.
Of course, in a few sections where the soil is three feet deep—as I am told it is in the Illinois corn belt—all that is needed is to loosen up the soil to the depth mentioned, and add old manure. If the removal and bringing in of so much new soil is too harsh on the pocketbook we must proceed in a more economical way. If the soil is clayey in texture, mix with it sifted coal ashes or sand, and the coarser part of the ashes may be incorporated with the soil in the lower foot of bed. Remove the top one-foot layer, and set it aside; throw out the bottom soil to the remaining depth. Break it up finely and, in replacing it, besides the coal ashes or sand, add fresh strong manure, placing it in horizontal layers—say three inches of soil, and then a layer of manure four inches thick, when gently tamped down; or make the layers slantingly—say at an angle of about forty-five degrees. This will add humus to the soil, and allow air and moisture to penetrate it. Then put in the original top layer, mixing it with old manure. No fresh manure should touch the root of a plant. The fresh manure at the bottom of the bed will be well rotted by the time the roots reach it. After the top layer is put on you will find the bed raised up six to eight inches above the lawn, which is all right; it will settle enough in time. At all times break up the soil into fine particles, otherwise a lump of clay will remain a lump, and is of little value for plant use.
In making beds or shrub holes close to buildings having a cellar, one generally has to remove entirely all the soil, as that present usually consists of the deeper soil from the cellar excavation, mixed with bricks and mortar—few flowers root well in brick.