This section is from the book "How To Make A Flower Garden", by Wilhelm Miller. Also available from Amazon: The Well-Tended Perennial Garden: Planting and Pruning Techniques.
Plant thickly enough to form eventually a mass of foliage sufficiently dense to completely hide the ground. Scattered plants about a newly raked bed may look neat, but so would perfect rows of painted stakes. Neatness can be more perfectly attained by the close grouping of plants of similar foliage. Too great a mixture of leaf-forms and colours often gives a tangled and untidy effect. The aim is the happy medium between the sameness of a too large group of one species and the careless mixture of many species. Make the groups decided enough to be called groups in comparison with the area of the planting, but let them be irregular and blend into the surrounding groupings with pleasing contrasts.
A very effective way of planting, especially where the border is long, is to use a large quantity of a few kinds of plants which follow each other in bloom through the season, and to plant the whole border in small groups, so that at one time the entire border appears attractive with flowers of one kind and of one or perhaps two colours, to be followed by a flower of another colour. This method changes the colour effect of the whole border almost every week, but it of course cannot give the effect of a solid mass of flowers, as would be the case if the same list were planted, each kind in a plot by itself. A list for this purpose to follow each other quite closely through the summer might be: Yellow daffodils, purple German iris, rose and white peonies, scarlet Oriental poppies, Japanese iris (white, with pencillings of colour), yellow day-lilies, monardas (red), phlox (white, or nearly so), rudbeckias (yellow), purple New England aster, and hardy pompon chrysanthemum (pink and white). If a larger list, with plants of several colours appearing at the same season is used, the effect is entirely different, and care will be needed to obtain the more pleasing contrasts of colour.
A fine ted of grasses at the Pan-American. The giant reed Is in the background (Arundo Donax)- in the middle are culaliss (properly. Miscanthus); the plum, grass in front is known to gardeners a. Pennisetum longistylum.
The preparation of the beds for perennials should be very thorough, especially as the soil cannot be deeply dug or greatly enriched afterward. If the subsoil does not provide sufficient drainage to prevent water staying on the surface of the ground or the soil from becoming excessively wet during the rainier seasons, then under-drainage to a depth of at least two and a half feet will be necessary.
A first-class perennial bed, suited to sustain a large variety of plants in vigorous growth, should have the ground made loose to a depth of two feet. It would be best to have the entire two feet made up of surface soil, but it is not necessary. A satisfactory method is to throw off the surface soil and then dig over the subsoil and mix with it a fair amount of manure, bone and wood ashes. If the soil is clayey or sour there is nothing better than screened coal ashes to make its condition satisfactory. An application two inches deep to a foot of soil will loosen a stiff clay, and it will stay loose. Sand will answer to the same end, but not as well.
The crown imperial, an old time garden favourite, which comes up with a rush in early spring.
The top soil should, if possible, be a good loam, and be at least one foot deep. It should be well enriched with well-rotted manure, bone and wood ashes, or other mineral fertilisers, and put in a finely pulverised condition. The growth of vegetation cannot be vigorous without a deep, rich, well-drained soil. Keep the surface soil rich, and do not get part of the subsoil mixed with it, as many of the garden plants are shallow-rooted and need a very mellow soil; and further, a good friable surface is needed to allow the growth of annuals and small plants, especially those raised from seed. A good depth of soil gives a lower feeding-room for the strong-rooted plants, and allows the growth of more shallow-rooted plants among them, with far better results than could possibly be obtained on a thin soil.
An example of companion crops in floriculture - peonies and Lilium superbum.
When purchasing plants for a border, take pains to obtain good, healthy stock, and see that it is carefully planted as soon as received. The best season to transplant any particular plant is while it is yet dormant and just before its roots start to grow. Plants in general, and early flowering ones in particular, make considerable root growth in the fall. A good rule to follow is: Plant in the early fall those species that blossom before July, and in the spring those that bloom later in the year.
If it seems best to make the planting all at one time, then early fall will perhaps be the best season for the greatest number. Fall planting should be early, so that the plants can become established in the soil before freezing weather. It is of course quite possible to move plants at any season, but more care must be used.
A well-drained, deep soil under the plants is the first and best protection. Too much water in the soil and too weak a root system, with the alternate freezing and thawing, are the main reasons for the winter-killing of otherwise hardy plants. If the beds are given a dressing of short manure in the fall, just sufficient to cover the earth without smothering the crowns of the plants, it will prevent the too quick freezing and thawing.
Plants that are really tender to cold must be mulched to keep the frost from the roots. This can be accomplished with any material, such as straw, leaves, etc., that is open enough to form interior air spaces and so be a poor conductor of cold. It is well to place this material in heaps over the crowns of the plants so as to at least partly shed the rain. The soil must be extremely dry to injure an established dormant plant, but it can easily be too wet.
Shooting star, or Dodecatheon.
When, after a few years, the border becomes too thick or the clumps too large to give satisfactory flowers, some removal of plants and division of roots will be necessary. In general, do not separate the clumps until they show very plainly that they need it. The best season to divide any plant is the same as the best time to plant it, which is just before its roots start to grow.
An effective border-planting against an office building.
It may sometimes be best to water the border during severe drought. Do it this way, or do not do it at all: Give to each square foot of the bed a two-inch covering of water as fast as the soil will take it up. The continual application of a little water not only hinders the rise of water from the sub-soil, but tends to bring the roots to the moister surface, and so not only crowds them into a smaller feeding space, but makes the plants less able to endure the next drought, and less hardy for the winter.
The tulip-poppy (Hunnemannia), a Mexican plant allied to the California poppy.