If there are signs of either black or brown rot these areas should he carefully cut away until clean flesh is reached, taking great care to avoid causing damage to the crown, as the young shoots are produced from this and not from the tubers. Should part of the crown be affected also, the diseased areas should be pared away very carefully indeed, because if only the smallest portion can be saved there is a possibility that this will contain an eye and that this will produce young shoots.

It is an advantage to dress the beds before planting with Gammexane at the rate of 1 ounce per square yard to discourage pests. And it is as well to put down slug bait as there may be slug eggs in the soil which will hatch out. When the beds have been prepared, the sets of tubers should be gently pressed into the compost, covering the tubers only, leaving the crown free of the earth.

Flowering depend on the amount of heat and to the variety; some varieties are naturally quick whilst others take so long that it is very easy to become impatient. The majority of varieties, given bottom heat of say 70 F and top heat of 5o to 5 5 F, will produce growth buds in ten to fourteen days and cuttings suitable for propagating in three and a half to four weeks after setting up.

Some varieties such as Doge will produce very thick stubby growth, often with hollow stems and in comparatively small numbers; these growths if taken as cuttings are usually very slow in rooting, in many cases proving almost impossible to root. It is advisable in such cases to remove the very stout growths close to the eye, quite early after development, in order to allow the subsidiary buds to develop.

Some authorities advocate that the prepared tubers should not be benched or boxed up straight away but should be placed upside down in a warm place in the greenhouse, and gently sprayed daily with warm water, to which a little permanganate of potash has been added, until the tubers begin to plump up. There seems to be no great advantage in this, unless the tuber is very shrivelled, provided the plunging medium is itself fairly sterile and very open in texture.

Still it is unlikely to cause harm and there may be some value in this pre-plunging treatment; certainly it is likely that any dormant fungus or bacterial infection present will develop under spraying and that this will be easily detected and preventive action taken, whereas it may develop unseen under cover of the soil and remain unchecked if the tubers are benched up immediately after trimming.

Should drainage be suspect, therefore, the plot should be “double dug”, preferably in the winter to enable the frosts to break down the clay, and also to allow plenty of time for the soil to settle before planting time. Double digging will not be necessary except at infrequent intervals, because, as was said before, the dahlia is not be incorporated in the lower spit but this should consist of only the coarsest material.

Should the soil in the dahlia plot be very heavy and show an excessive tendency to waterlog during wet weather it may be necessary, in extreme cases, to lay land drains.

The dahlia is intolerant of stagnant ground, and will give poor results under such conditions, so that, though the provision of such a system is undoubtedly a laborious task, the improved results due to better drainage will justify both the expense and hard work involved.

If the soil is in very good heart, and particularly if not much material is available, then it is probably best to retain for use as a mulch later in the year when the plants are beginning to grow away, thus serving a threefold purpose of water conservation, feeding and later manuring when the ground is dug at the end of the season. But if the soil is not in good heart some manure must be dug in.

As far as the dahlia is concerned this normal practice seems to give the best results, and, in view of the current shortage of bulky manures for top-dressing, is economically the soundest method.

This is a valuable fertiliser on heavy ground, supplying a percentage of phosphates as well as calcium and helping to break down the ground in addition.

In a few cases growth is almost completely inhibited and dwarf plants result. Just one word of warning here, though a check may explain dwarfness in stature, and the plants may in fact be healthy enough apart from this, it is unwise to assume that this is so-the most likely reason for dwarfing is attack by virus organisms, and a heavy attack at that, and the only solution is destruction of the affected plants.

It is usual also to plant these pompons in the less rich parts of the which are naturally small and neat in flower. These often do better in moderately rich soil, provided the plants are encouraged to make a mass of flower, which will ensure that the blooms are not too large.

With regard to planting distances, the old gardeners always allowed very ample space for dahlias, but the more modern tendency is to plant much closer so that the plants grow together in the rows and offer some support to each other, in addition to that given by the stakes and ties. This closeness of planting must not be overdone, as the dahlia is a strong growing plant after all and must have ample room for development. The space allowed for all the double varieties, except the small pompons, should be a minimum of 2 ft 3 in. to 2 ft 6 in. between plants in the rows with a minimum of 3 ft between rows.

A very excellent compromise which can be thoroughly recommended, and which will probably give the finest results of all, is to plant in double rows with plants 2 ft 6 in. apart in all directions, that is in a staggered formation, with a wide pathway between each double row at least 3 ft to 3 ft 6 in. wide. These distances may be increased a little, but it is not necessary to exceed 3 ft between the plants in the rows or more than 4 ft between rows.

If the plot or bed is large enough to take a number of rows it is very much a matter of choice whether the rows run the full length of the border or crossways across the border; the main point is accessibility.

The soil on three sides of the plant is never trodden on, a very worthwhile consideration when it is realised that the roots of the dahlia come very close to the surface later in the season.

Whether a plan has been prepared or not the question must ultimately be when to plant. This is a most important decision and must not he taken lightly as the ultimate success of the dahlias may depend upon the rightness of the answer.

There is one thing that cannot be overstressed, the dahlia should be planted as soon as soil and weather conditions permit. And this often means that the calendar has to be very largely ignored and the weather reports studied instead, together with an intelligent anticipation of local conditions. Where plants are concerned it is useless planting when the soil is cold and the weather is cold or there arc icy winds expected.

If this plan is adopted it is best to plant in groups of three to six dahlias, again carefully chosen as to height, putting a block of taller varieties at the back of the border, with dwarfer perennials – not too dwarf of course – in front ; or a group of varieties of medium height, in front of tall perennials such as the rudbeckias and so on. The variations on this theme are unlimited.

The condition of the soil is a wonderful guide. If at the usual planting time it is fairly warm, just nicely moist and really workable, by all means go ahead with planting, particularly if the weather conditions are also reasonable. Obviously the type of soil and the situation will have some bearing on the matter, for a heavy cold soil will take much longer to warm up than a light well drained soil, and a sheltered site will warm up even more quickly.

Admittedly there is practically no skill required in growing these varieties but they are certainly as attractive as any other plant commonly used for bedding purposes, and have a season of growth greater than almost any other flower. Not much planning is required with these little beauties, as the colours seem to blend very effectively.

One of the major troubles will be insect damage, as the pests will tend to migrate from the less herbaceous stuff to the rich fare offered by the succulent dahlias. Dusting or spraying with good insecticides will minimise this undesirable factor.

Erecting a close boarded fence is not effective to prevent frost pocket if the garden is in the lowest position in the neighbourhood. In this case a close hoarded fence all round may help a little, but really it is very difficult to prevent frost damage in such situations by structural alterations.

Individual plants can be protected at planting time, but apart from this it will be as well to become resigned to losing the plants a little earlier than the luckier gardeners in more ideal sites.

A greenhouse, however small, is almost a necessity, though Again, although a very small greenhouse can be used, the twin difficulties of space and temperature variation render it less suitable so that it is both easier and better to invest in a larger structure if circumstances permit.

Other than this there are two means widely used today, both of which are designed to increase the clone, that is the stock of one variety without variation of size or colour. This can be done only by vegetative propagation, that is to take one part or other of the original plant and to make this part into a separate plant, producing stems, flowers and root stock identical with the original.

The usual argument in favour is that the plant raised from a cutting has a completely fresh circulatory system, for no part of its nourishment is obtained via old tissue. As the divided tubers produce fresh stems from the crowns, and as fresh roots develop from these, it is doubtful whether this argument has much weight.

The tubers may be benched up from January onwards, although the average amateur will probably get sufficient plants as well as better results in a very small house, if this part of the procedure is delayed until the beginning to the middle of February. Before benching up, the sets of tubers should be carefully examined, removing any broken tubers with a very sharp knife, and cutting off any dried fibrous roots which remain.

Provided the ground is fairly moist it should not be necessary to water the plants in. The roots will enter the soil is advisable to water in, not heavily but giving about a pint of water to each plant.

Some growers on heavy soil consider that this practice is liable to lead to waterlogging, when the plant to all practical purpose drowns in stagnant water, but this is unlikely. On the other hand, making the hollow is hard work and if the ground is mulched well, it will still soak up a great deal of water without the surplus running off.

Whatever form of staking is used it should be strong enough and long enough to support a well grown plant. With regard to length, it is sufficient if it is long enough to be driven 12 to 18 in. in the ground and still project out of the ground to a height 1 ft below the estimated height of the plant.

The primary step is actually taken the clay before planting when all plants in pots should be well soaked. Take out a hole in the centre of each depression with a trowel, wide enough and deep enough to take the soil ball of the plant quite easily.

Having marked out the plot and bed, driven in the stakes or marked the position for each plant in some way, it conies to the question of how to plant. And here a number of points must be considered. Some growers prefer to plant on the flat, that is to have a completely smooth surface to the plot after planting, some advocate planting in a hollow, which is filled in later, whilst others prefer to plant in a hollow which is allowed to remain all summer.

The label could be inserted in at the base of the plant, but is so easily lost that it is not advisable, unless very large labels are used, also it is not so easy to check the label for correctness of naming when the plants flower. Visitors too will be much more interested if they can ascertain the name of an attractive variety easily without having to stoop or grovel at the base of the plant.

There is sometimes a strange anomaly in some soils overlaying chalk, as they are occasionally acid. This is often the case where the garden is situated towards the top of a hill, so that the calcium is leached out of the top spit, with no replacement lime washed down from a higher level. If poor growth is evident, and there seems no explanation, this might he the answer. A soil test will soon tell.

A double row of runner beans, run up stout bean-sticks, desired, sweet peas, grown naturally in similar fashion to runner beans, will serve quite as effectively provided that they are well watered and constantly gone over to remove dead flowers and seedpods-this will help to prolong the flowering period and, of course, the life of the screen.

However, though bulky material is essential, it is inadvisable to incorporate this early in the winter. Any available animal the ground after Christmas, never before; in fact on light ground it is really best to retain as much manure as possible for the provision of a mulch in July.

Fortunately sulphate of potash is an ideal medium, though quick acting it is not easily washed out of the soil and is therefore available over a long period. This can be applied at the rate of 2 ounces a square yard when digging or it may be incorporated with the soil when planting. Wood ash is another very useful source of potassium, but it must be applied in large quantities to be effective.

For the enthusiast compelled to garden on chalky soils or subsoils, many problems arise, partly because the texture is usually light and has all the disadvantages normally associated with light soils, and partly because the dahlia does not appreciate an extremely alkaline soil.

Peat will help a great deal and, in any case, most animal and vegetable manures are substantially acid so that generous addition of any of these materials will go far towards settling the problem. It may also be necessary to add additional nitrates during the growing season.

It is also believed that the Abbe was the recipient of the first dahlia seed ever sent to Europe, in 1789, when he was director of the Royal Botanical Gardens at Madrid; at least there are no records of earlier introduction. Unfortunately very little is known of the subsequent treatment or development.

The so-called decorative dahlia would appear to be of extremely mixed origin. Interest in this particular variation developed at about the same time as the cactus flowered hybrids from Juarezii were becoming popular, and it is probable that they were no more than a parallel development, with some of the same blood in them.

Single flowered dahlias are flowers which do not exceed 4 in. in diameter, composed of a single row of ray florets surrounding the central disc. Star dahlias has small blooms with two or three rows of somewhat pointed ray florets, slightly incurved to form a cup shaped flower with a central disc.

Anemone flowered dahlias has blooms of various sizes composed of an outer ring of ray florets surrounding a dense central group of tubular florets, shorter than the ray florets but longer than the disc florets in the normal flower. Both disc and ray florets may be of any colour, including yellow. Collerette dahlias have one or more rings of flat ray florets, with an inner ring of small florets approximately half the length of the ray florets. Although fully double and semi-double varieties could conceivably be raised, only varieties with a single row of ray florets and one collar surrounding a central disc of ray florets are grown today.

The finely quilled varieties were styled cactus, and those with broader petals were classed as semi-cactus. The decorative were similarly divided into two classes, formal and informal. It was finally decided that the classification was becoming too complex.

Cactus dahlias also have fully double flowers without a central disc, at least not until the bloom is aged. The ray florets are usually pointed, narrower than those of a decorative, and revolute for a part of their length, that is, the petals tend to curve backwards across their width to form a tube for some part of their length. The florets can be either straight or tend to incurve.

Should the dahlia plot be an island site, with paths all round so that it may be seen from several sides, it will naturally have to be planned rather differently; the colour grouping will still be necessary, but the taller plants will have to be placed in the centre with the shorter plants graduating down on all sides to the pathways.

Even if the doubtful truth of the saying that “flower colours do not clash with each other” is accepted, this will not eliminate the fact that all dahlias do not grow the same height, and that if a dozen dahlias are planted, it is desirable that a dozen should be seen.

In this case the variation in height from hack to front should not he too great or the contrast will look rather odd. A variation of 02- to z ft in height between back and front rows will be ideal.

One of the first things to be done, once it is known how many plants are available of each variety, is to make a rough plan of the border, or borders, giving consideration to height, colour, type and size of flower and planting distance.

There is no reason why the back row should consist of large flowered dahlias, any more than that the front row should consist of small dahlias. Many giants are borne on comparatively dwarf plants, whereas some of the smaller bloomed varieties, such as Glorie Van Heemstede, will attain a height of almost 6 feet, and be very suitable for the back of the border.

An admixture of different sized blooms, together with a variation in formation and colour, graduating down from the back to the front, will stop any tendency to look formal and stiff.

If frost does seem likely, then the plants should be covered if possible. A sheet of newspaper, twisted into a cone and dropped over each will give complete protection. Large pots may be used to cover the dahlias.

Some growers in fact leave such a pot by each plant until the danger of frost has completely passed. As an alternative a twist of straw may be tied to the stake and teased out to cover the plant at the base. Cardboard boxes may be used-the choice of covering material is almost limitless.

This is particularly so with the giant varieties, because, after all, there is little point in growing these varieties unless the blooms are big; if smaller blooms are required then varieties which naturally produce bloom of lesser size should be grown. For garden decoration it is not necessary to restrict to the same degree.

Small decorative and cactus will require little de-branching, unless the plants produce an unduly high number, when it is advisable to thin out the weaker shoots. Again variety and soil considerable bearing on this point, a weak growing variety on light soil for instance should be restricted to no more than eight or nine side branches. Treat miniature varieties similarly.

The time taken from each particular stage to the next will vary a little with the weather conditions prevailing, but the ratio will remain fairly constant from variety to variety, so that the approximate time of bloom from a stop on any given date can be roughly estimated.

The actual number that will be allowed to develop on any particular plant will naturally vary in accordance with the size of bloom, the vigour of the variety and the strength of the ground in which it is grown. It must be obvious, therefore, that a very fair knowledge of the capabilities of the dahlias grown, and of the soil, must be acquired.