- Flower Introduction >Perennials
The time for planting is controlled by the nature of the soil and climatic conditions. Where the soil is of a light and well drained character certain advantages attend the end of October; this will enable the plants to become established before the dormant season and they will have the advantage of starting renewed life the following spring as established plants. Where, however, the soil is heavy, it is unsafe to plant until new growth appears in February or March.
While a certain amount of latitude is permissible in deciding whether to plant in the autumn or spring, so far as herbaceous perennials and shrubs are concerned, there are others that must only be planted at certain season of the year if unsatisfactory results are to be avoided. Daffodils, Tulips, Bulbous Iris, Scillas, Chionodoxa, Snowdrops, Crocus and, in fact all spring-flowering bulbs should be planted as early as possible in the late summer autumn.
On the other hand the half-hardy bulbous subjects must not be planted in the open earlier than mid March; these comprise Gladioli, Tigridia and Watsonia. If required for some color scheme, rather earlier than their normal season of flowering, the corms may be potted in late autumn and brought on in gentle heat for planting out-of-doors in April or May. If a green-house is available they may be transferred to larger pots and brought into flower under glass some weeks earlier than out-of-doors.
The choice of site is important, except where special conditions are recommended, this should be in that part of garden enjoying maximum sunshine and providing protection from the prevailing wind. Such protection is especially important for all plants such as Delphinniums, Sunflowers, etc., as even the sturdiest support will be insufficient against winds of gale force.
Preparation of the soil is very important, for upon it ultimate success or failure will depend. Where the soil is light and, in consequence, well drained, some form of moisture-retentive humans will be necessary. In these days of mechanized agriculture, farm-yard manure has become an extremely scarce commodity in many localities, making it necessary to find some other medium to take its place. Granulated peat, supplied in bales, in an excellent substitute, being a great moisture conserver. The peat will be perfectly dry when received; it should be broken into fine particles and then thoroughly soaked with rain water for preference, otherwise tap water may be used. This is very important for it buried in a dry condition; the peat will remain dry and create drought conditions at the roots of the plants. Before drenching, fertility may be achieved by adding one six-inch pot full of bone meal or fish manure or a mixture of both to each full barrow load of peat and well mixed. This peat mixture should be buried about nine inches deep so as to form permanent sponges that will provide the necessary moisture for the roots should a drought occur during the summer.
All soil should be tested for lime deficiency, which is more likely to occur in light sandy soils than in heavy loam. If the plants to be grown are lime lovers, lime may be applied immediately after digging so that it may be washed in by the rains. A mild form of lime, such as chalk or hydrated lime is best soils and a stronger type, such as burnt lime, for heavy.
Staking will require attention as the plants of tall or medium height develop. Except for plants of a bushy habit such as Dahlias, that form a main central stem, single stakes in themselves are useless and create an ugly trusted-up appearance, utterly destroying the true habit of growth of a plant. For plants of a spreading nature, such as Michaelmas Dasisies, Heleniums, Gyposphila and most composites, short twiggy pea sticks are unrivalled, and if placed in position before growth is very high the plants will grow into these supports and find strength enough to weather strong gales. Delphinniums, the tall Rudbeckias and sunflowers, are best supported with stout bamboo cane five or six feet long of which at least one foot is thrust in the ground. Each individual stem is ties to the cane with green twist or split rings. If the canes are painted green they will be inconspicuous.
The reminder of the maintenance consists in keeping the weeds under control, watering only if a prolonged drought renders this necessary, and giving protection from slugs and other pests by the application of a suitable pest-destroyer. It is important that if watering is practiced it should be continued with regularity whenever the weather is dry, otherwise the roots will be attracted to the surface and suffer from drought if the life-preserving moisture is absent. It is better not to water at all than to water at spasmodic intervals.
Most amateur gardeners will want to try their hand at increasing their stock of different plants. So far as herbaceous perennials are concerned, there are three main methods of propagation, viz. by seed-raising, division of the root-stock and rooting of cuttings (stem or root). Seed provides the most natural method of propagation, and seedlings are often more robust than plants raised by either of the other methods. It should be known, however, that where as seedlings of species come fairly true to type, those raised from garden forms often manifest great variety in color and habit. To obtain true stock of such varieties one or the other of the vegetative methods must be employed.
The life of a seed can vary considerably. Delphinium seed sown as soon as ripe will give practically 100 per cent germination; if sown a year later this will probably be reduced to 50 per cent or even as low as 25 per cent. Seed of Dictamnus if sown in late summer as soon as ripe will germinate satisfactorily in the following spring, but if kept until the spring before being sown it will not germinate until a year later, and may not germinate at all. Foxglove seed has given a full percentage of germination when sown five or more years after harvesting. These examples will give some idea of the variation in the longevity of the germinating capacity of seeds. It is best to sow as soon as ripe or, at the least, in the spring following.
For convenience seeds are sown in boxes about three inches deep or in earth ware pots or pans. The best compost consists of one part of sandy loam, one part of granulated peat or leaf mould and two parts of coarse rive sand. The seeds should be scattered evenly and not thickly over the surface and then covered with a thin layer of sand and the whole made firm by a short board made to fit into the box. Water with a hand syringe and then cover with a pane of glass which, in turn is covered with newspaper or some other opaque material. In the course of germination the compost should be kept in a moist but not wet condition. As soon as germination has taken place, all covering should be removed, otherwise the seedlings will become drawn and weakly in their struggle to find light. As soon as the first pair of true leaves appear the seedlings may be carefully lifted and pricked off into similar boxes or frames containing a compost consisting of one part sandy loam, one part peat or leaf mould and one part of coarse sand. Here they may be left during the winter, taking care, when the genus is perfectly hardy, to admit full air to prevent damping off. In the spring, when growth has reached an inch or so high, plant in the positions where they are to flower. Seed sown in spring requires similar treatment and, as the seedlings will not suffer a dormant period. Until the following winter, they may be planted in their permanent positions as soon as large enough.
Division of the root-stock is the simplest and most easily performed methods of vegetative propagation. As soon as growth is about an inch high in February or March the whole is lifted, the soil washed off by immersion in a bucket of water and the individual crowns, each with a piece of root attached, broken from the remainder, planted out where they are to flower and shaded with pots or boxes for about a week to prevent wilting whilst they recover. There are certain exceptions to this rule. Bearded irises are best lifted and the rhizomes cut into pieces, each containing two or three eyes or growths, planted out immediately, and giving a top dressing of lime to maintain a healthy condition. Herbaceous peonies are treated likewise in September or October, but the dressing of lime is not necessary in this instance.
Cuttings provide the best method of large-scale propagation, and this method is favored by most professional horticulturists. Top ( or stem) cuttings are taken in late winter or early spring just as new growth has reached an inch or so high; this method is particularly useful for delphiniums, Lupins, Michaelmas daises and similar plants. Cuttings are taken with a heel of the parent crown. They are carefully trimmed so as to remove any rough edges where water may lodge and cause decay. These are inserted in pots, boxes or frames containing compost similar to that recommended for seed sowing, taking care that there is a little sand at the base of each. They must be shaded for a fortnight or more until callusing has taken place, and fro then onwards the shading may be removed except when there is particularly warm sunshine liable to cause wilting. Watering is most important, and f the cuttings are over-watered it is very probable they will decay before being able to callus.
The water required by an unrooted cutting should be just sufficient to maintain it in a fresh condition and, until roots have been formed to suck in a greater quantity of water, this should be given very sparingly and then only by means of a fine spray from a syringe. As soon as the cuttings have produced sufficient roots to enable them to be lifted with a soil ball held together by a mass of fibrous roots, they may be planted out in their flowering positions.
Root cuttings may be taken in late summer, early autumn or in winter. The plants are lifted and the strongest roots cut away. These are cut into pieces of about a quarter of an inch long and then inserted in the usual sandy compost, taking care that they are in a vertical position about a quarter of an inch below the surface and the uppermost portion comprising that which would normally be nearest the parent root. If there is any doubt in regard to the latter question, place in a horizontal position about half an inch below the surface. These must be watered sparingly and may be planted out when they have developed sufficient root and top growth.
Bulbous subjects are usually propagated by means of offsets, removed and planted out when the parent bulbs are lifted as the foliage ripens. Plants with corms, such as gladioli, will often produce a mass of small corm lets, the size of a pea or less, at the base of the corm; these may be sown at the normal planting time to develop into flowering size corms in two or three years’ time. Lilies may be propagated by means of bulbils, produced in the leaf axils of some species and hybrids and from scales removed immediately after flowering and placed in pure sand until small bulb lets have formed. The last-named method requires some experience and is best left in the hands of the professional grower.
Cuttings of the shrubs included in this book are best taken in late July or august of half-ripened wood, cut at a node or leaf joint and rooted in a sandy compost as recommended for certain herbaceous perennials. They should not be planted out until the following spring.