GENERAL ARTICLES ON CULTURE
(Applying to all Types of the Dahlia.)
Includes
Situations and Soils
Propagating and
Glasshouse Management
Manuring, Watering,
Lifting and Storing
Enemies and How to
Deal With Them
Raising of Seedlings
SITUATION AND SOILS.
BY P. W. TULLOCH.
REVISED BY J. CHEAL.
IT is not every amateur who is so fortunate as to possess an ideal situation in
-which to grow Dahlias. Notwithstanding this, in order to understand what are
the conditions which, combined with proper culture, -will tend to secure the
greatest success, it will he well to describe the ideal site, so that the
intending grower may approach it as nearly as possible.
The main requirements are three in number: first, a deep and naturally good
soil; second, a situation where there is ample protection against high winds,
without direct shading; and, third, an abundant supply of water near at hand. If
the first of these conditions be not satisfied, the soil of the garden being
shallow or not of the right character, suitable soil can, in most districts be
obtained in the neighbourhood at no great cost. On the outskirts of a town where
new roads are being made, fine soil can often be obtained for the cost of
cartage only.
Dahlias, however, grow on a very wide range of soils, so that deep cultivation,
and the importation of manure and extra soil will enable the grower to succeed
in many places which at first may appear very unsuitable.
A perfect situation would be a piece of ground sloping gradually to the south,
and surrounded by high trees at such a distance as to effectually break and hold
the wind -without being near enough to give direct shade to the plants, or
extend roots amongst them. Walls or buildings may afford helpful protection
provided they are placed so as not to encourage draughts, but in the proximity
of the Dahlias the best substitute for trees is to plant a thick row of runner
beans round the bed, and stake them with the tallest pea sticks obtainable. The
row should be 6 feet from the nearest plants on the south side, to avoid shading
in the autumn when the sun is getting low. If the ground be in an exposed
position, and a long narrow strip can be selected for the plants (say 60 plants
in three rows, 20 in each, such a protection would defy almost any gale.
If a stream of water runs near, a small, deep pond should be constructed in its
bed, or in connection -with it, capable of holding a sufficient supply of -water
to last through the summer, when the stream will probably be dry for a time. If
the only water supply be that from the waterworks, tubs or zinc tanks should be
placed near the bed, in which the water may stand whilst it becomes softened and
warmed to the temperature of the air.
The best soil for Dahlias is undoubtedly one of a heavy, loamy character, which
should, if possible, be 18 inches in depth, perhaps, -with a clay subsoil. If
the soil be light or sandy, it will be advisable to import clay in the autumn
and spread it over the surface. It will be broken to powder by the winter
frosts, and as soon as the ground is dry enough in early spring it should be
incorporated and well mixed with the native soil below. If the soil is heavy and
the ground flat or low-lying, the plot selected will be greatly improved by
drainage if an outlet for the water can be found.
I need only add that the grower who wishes to succeed should give his plants a
bed entirely to themselves. The advantage of this is that, as soon. as the
tubers have been lifted in November or December, the ground can be trenched or
dug with freedom, and left rough for the winter, whilst manure or lime can be
worked in if required. If the soil be heavy, it should be well and deeply forked
over in March, -when dry enough, and if this operation is repeated again at the
end of April or beginning of May, so much the better for the plants -when bedded
out a month later.
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PROPAGATING AND MANAGEMENT UNDER GLASS.
By P. W. TULLOCH.
Revised by S. MORTIMER.
THE new year of the Dahlia grower may be said to commence on the day -when the
old tubers saved from last season are removed from their winter quarters and
started into growth for the purpose of obtaining cuttings.
Instructions for propagation on the large scale required by the professional
grower need not be entered into very fully, as this chapter is mainly written to
give information to the small grower and amateur.
The professional grower requiring some thousands of plants must make an early
start, placing his stock of old tubers and pot roots in heat early in January,
and taking all growths for cuttings as soon as they are long enough to handle.
It is a good plan to cut off and discard the very strong early growths that are
thrown up, especially in the Show and Fancy section, as even, if they strike
root (which they often will not do), they rarely make good plants.
One essential matter to be remembered by both professional and amateur growers,
in propagating Dahlias, is that they must not be given too much top heat.
If the small grower is in possession of a greenhouse with artificial heat,
provided through the medium of hot water pipes, his propagating can be done by
placing the tubers in a bed of mould sufficiently deep to cover the roots,
whilst leaving the crowns bare, and then raising the temperature of the house to
about 60 deg. or 70 deg. Fahrenheit, during the day time, though it may be
allowed to drop to 45 deg. or 50 deg. at night. The operation may, however, be
performed quite successfully in a small cold greenhouse, measuring only a few
feet either way, by making up a hotbed, and stimulating the heat by means of an
ordinary oil stove.
The plan adopted by the writer, in a small house measuring 12 feet by 8, is to
have a shallow- iron or zinc water tank constructed to fit on to the greenhouse
stage. The space underneath the stage, and corresponding to that covered by the
tank, is enclosed by boarding in the form of a cupboard, with a door in the
centre. Inside the cupboard is placed an oil stove capable of lasting for 14: to
16 hours, and with this the temperature of the water above may be regulated to a
nicety, after a few days experience.
The depth of the water tank need not be more than 6 inches, whilst its length
-will, of course, be dependent on the space required according to the number of
tubers to be started.
On the top of the tank arrange a bed of mould as directed above, with some
boarding round the edge to prevent its falling off; and in this place the tubers
up to their crowns, but, as the temperature of the house may sink to freezing
point or lower at night, it will bo necessary to protect the crowns also : which
can be best done by covering the mould and upper parts of the tubers with a few
inches of cocoanut fibre. The latter, although covering the eyes, will not
hinder their development, and being a light and clean substance, can easily be
pressed aside with the fingers when the young shoots are long enough to be
removed.
A. thermometer should be plunged in the bed with its base about 2 inches from
the roof of the tank, to enable the temperature of the soil to be regulated;
this should be about 55 deg. to 60 deg. F., when the tubers are first put in,
and should be raised gradually to about 65 deg. to 75 deg. during the first
week, at which level it should be afterwards maintained, never being allowed to
exceed this.
The soil and cocoanut-fibre should be moderately dry when the bed is made up,
and no water should be given for the first ten days after the tubers have been
covered up.
By this time, some of them will have commenced to throw up shoots, and to these
an occasional watering should be given with water of the same temperature as the
house in which they are grown, but none should be given to those which have not
started unless the soil below them has become very dry, and then it should be
given but sparingly, as, until a tuber has once started there is always a danger
of its becoming rotten if kept too moist.
About the end of January, or early in February, is the time for planting the
tubers in. the hotbed, but, unfortunately, no fixed period can be named as the
interval before growth commences, owing to the irregularity of the different
varieties in this respect. Some will be throwing up strong shoots in less than a
fortnight, the majority within three weeks to a month, a few will lag behind for
two or three weeks longer, and others, after the grower has removed them in
despair to some corner given up to rubbish, will perhaps be found to have
started into growth later in the season, when the weather has become warm. This
irregularity is the more annoying because, as the cuttings are taken, from the
tubers, the bottom heat space is required for them in their striking pots, and
to provide flits space each tuber should be removed as soon as sufficient
cutting's have been obtained, but it is always wise to take rather more cuttings
of a variety than the number of plants actually required, in case a few should
fail to strike, or to root well afterwards.
The shoots may be taken off when they have grown to about 3 inches in height.
Some tubers will throw shoots singly from different eyes round the crown; these
are very easy to strike, and if only a limited number of plants is required,
they should be picked out with the point of a sharp knife, with just a small
piece of the tuber attached.
Other tubers will throw shoots in clusters from one or two points only, and if
many plants are not wanted, the^e clusters should be cut out whole when the
shoots have reached an average height of about 3 inches, and then separated
carefully with a knife, retaining a small piece of the tuber with each, if
possible. If many plants are required, the shoots should be removed
individually, by cutting them off just below the lowest joint that can
conveniently be got at without damaging either the others or the eyes that will
be coming from the base of these shoots themselves.
Before commencing to take cuttings, have the pot^ and potting soil ready at
hand, and see that the pots have been washed thoroughly clean if they have been
used before, and that none of the old earth is, sticking to them inside. The
soil should consist of an equal mixture of turf mould and coarse sand; but the
former must contain no grubs or wireworm. If the soil has been brought into the
greenhouse some days before it is required, it will be dry enough to pass
through a fine sieve; this will be found the best and safest plan to adopt. In
potting, I always use 2½ and 3-inch pots, and put four or five cuttings in each.
First I fill as many pots with soil as will be required, placing as large a
piece of flat crock at the bottom of each as can be got in. This is to prevent
the possibility of worms effecting an entrance, for it will be a poor outlook
for the cuttings if they succeed in doing so. The pot must then be surfaced with
silver-sand. Next I fill the pots to the rim two or three times over with tepid
water, to insure the soil being thoroughly soaked through; and, having taken off
the cuttings, I insert them about 1½ inches, or up to the second joint from the
base, keeping them round the edge of the pot. Then, having written a label with
the name of the- variety and the date, I plunge the pot into the hotbed, right
up to its rim.
Cuttings of different varieties are as irregular in the time required for
striking as the tubers are in starting. The average time is three weeks, but,
while some will be well rooted in a fortnight, a few will take six weeks, or
even longer. If, however, at the end of a month, there is no sign of roots, turn
them out; break the earth off carefully, in case there may be a tiny root just
coming", and repot into fresh soil. Curiously enough, cuttings that. have
refused to strike for five or six weeks, will often do so within a week after
this has been done. Another curious fact with regard to tubers that start late,
and cuttings that do not strike readily, is, that when once struck, they often
go ahead with amazing rapidity, and finally outstrip the earlier ones. Last
season Cactus Dahlia Mrs. Edward Mawley was so slow both in starting and
striking with me, that, despairing of ever getting any plants, I ordered some to
replace my own; but, no sooner had I done this, than the whole lot struck within
a few days (all having been repotted), and so fast did they grow, that by
planting out time they were among- my best plants, and actually the first Dahlia
bloom of the season was cut from one of these in the second week of July.
At the end of about three weeks from the date of potting, the pot-form should be
carefully turned out of the pot in the usual way, to see if some or all of the
cuttings have struck. If two or three only have done so, remove them carefully,
replace the soil broken away by fresh soil, and return the pot to the bottom
heat. The struck cuttings should then be potted singly in 2 or 2½ inch pots, and
again plunged in the bottom heat. The soil for this second potting should
consist of 50 per cent. of turf mould, 25 per cent. of leaf mould, and 25 per
cent. of coarse sand.
With regard to watering; all cuttings that have not struck, should be well
soaked with water of the temperature of the house in which they are grown, about
every four days, but after being struck and repotted, less frequent waterings
will be necessary, though the soil must always be kept moist. It is also
advisable to spray all cuttings and young plants alike with a fine syringe in
the evening, using water that has been standing in the greenhouse for some
hours. This may not be so necessary in a house heated by hot pipes, but where
other modes of heating are practised, the air becomes very dry, too dry, unless
a considerable amount of moisture is distributed to counteract it.
From the time when the young shoots first appear above the cocoanut-fibre it
will be necessary to keep the temperature of the house above freezing-point
during the night, and to do this a second oil stove will b& required in cold
weather. This stove can be placed in the centre of the house, or on the opposite
side to the hotbed, and should have a pan of water placed over it, so that the
necessary amount of moisture in the air may be maintained by evaporation. To
adjust the stoves for the night it is necessary to forecast what the conditions
are likely to be, and the best way of attempting this is to hang- a thermometer
outside a sitting room -window on the north side, and watch it carefully during
the evening. If it stands at, say, 42 deg. at 6 or 7 p.m., and at 10 or 11 p.m.
it is still above 40 deg., a very cold night is improbable, but if, on the other
hand, it is found at the later hour to have fallen to 36 deg. or 37 deg., a
frost before morning may be expected. With the assistance of a thermometer
inside the greenhouse (a minimum-registering one will be the best), in addition
to the one plunged in the hotbed, the regulation of the night conditions -will
not be found difficult.
During February and March, a maximum day temperature of 50 deg., with a minimum
of 38 deg. at night, will be all that is required, but on sunny, or dull, warm
days, this day maximum is sure to be exceeded, especially in March, but when due
to such natural influences, no harm will result if plenty of air is admitted.
Draughts must be avoided in the case of cuttings, but fresh air, both for these
and for young plants, is absolutely essential, and to supply it the roof
ventilation must be kept open more or less both day and night, even in the
coldest weather, whilst on mild days the side ventilator on the opposite side to
the hotbed should be opened also. It is advisable to have the hotbed on the
south side because the cuttings, and young plants also, for the first few days
after being repotted, must be protected from the sun, and the glass on the south
side will require to be whitened in anticipation of the first batch being
caught. Do not have the whole roof shaded, however, as it is only the direct
rays of the sun that have to be guarded against, and apart from this the utmost
light obtainable is required.
We now pass from the propagating stage to the management of the young plants
during the fickle weather of mid and late spring. After these have been in their
2½ or 3-inch pots for about three weeks, they will require potting on into
5-inch pots, and should then again be plunged in the bottom heat. One of our
best authorities, Mr. Robert Fife, says: " Warmth at the root and comparative
coolness above, are the conditions which will best insure their giving a good
account of themselves in their future stages of development." And there can be
no doubt that bottom heat with plenty of fresh air is the best of all
treatments. The effect is that, whilst the growth of the green plant itself is
retarded by the low average temperature of spring, the root is progressing under
the natural conditions of summer; and consequently, when summer itself arrives,
the upper growth experiences all the advantages derived from a strong and solid
foundation laid well in advance of its requirements.
By the middle of April the grower will have most of his plants installed in
5-inch pots, and his hotbed space will barely suffice for all, -wliile if the
weather is tine and warm, there will be a danger of the plant getting drawn by
the day heat in the greenhouse, despite the door and all ventilators being
thrown wide open.
It will, therefore, be advisable to transfer all well rooted plants to a frame
in. the garden before the end of the month, and, in anticipation of this a
hotbed should be prepared a fortnight or three weeks in advance. On this is
placed the frame, but the plants must not be put into it until the temperature
of the bed, as shown by a thermometer, plunged to a depth of 6-inches, has sunk
to 100 deg. If this is the temperature at mid-day, the average for the
twenty-four hours will be no more than. 90 deg., and the pots may then be
plunged to half their depth at first, and to their full depth about ten days
later.
Before transferring to the frame, a thin stick should be put to each plant as a
support in case of wind, and tied to the stem with bast. The stick should not be
put in too near the stem or it may break through one of the main roots. At the
same time it will be as well to turn out any plants that are growing very
strongly, and transfer them to still larger pots, but this must only be done
when the soil is just moderately moist. If it be either very wet or very dry,
the pot-form may break away with half the root attached: a loss which will never
be thoroughly recovered. About this time, plants of new, or additional varieties
ordered from the nurserymen, will be arriving, and these should be immediately
transferred to larger pots, and shaded for tliree or four days before being
placed in the frame with the others. Plenty of fresh air by day, and protection
from frost at night must now be the order of things. The heat from the manure
will be sufficient to keep out the frost with the frame nearly or quite closed
on cold nights—whether nearly or quite, must depend on the minimum thermometer,
which should be placed inside the frame, resting on one of the pots, not lying
on the manure; but on the really mild nights, such as -we sometimes get, even in
April and May, the lights need not be more than two-thirds or three-quarters on.
In the daytime, if the weather be fine and warm, they can be removed altogether,
but if windy or wet, a good plan is to leave them fully on, but raised up
several inches at each end, either on long beams or thick poles laid across
under them. By the middle of May there will be little heat left in the manure,
and after this, a soaking from the rain will not renew it, but, while it is only
slowly cooling, a wetting will have the effect of reviving it considerably hence
the rain should be kept out, because whiat is wanted is a gradual decrease of
heat during this month to harden the plants off by degrees, before planting out
time.
During the time that the plants are in the frame they should only be watered
-when rather dry, and then. watered thoroughly. Too constant watering will
hinder root growth, but when the sun is very hot, a careful watch must be kept
to see they do not remain dry too long.
And now a last word on the important subject of repotting. Dahlia plants in pots
should never at any stage of growth be allowed to approach the pot-bound state,
but the most important stage in this respect is when they require potting on
from their 5-inch pots. It must be realised that the main roots, which later on
form the big tubers, grow very fast at this stage, and if they are allowed to go
on running round and round the side of the pot, and entwining themselves into
each other, they will never succeed in disentangling themselves after being
planted out, and consequently can never obtain that extensive hold of the soil
which is so necessary if fine, deep, exhibition blooms are to be obtained.
I get most of my plants into 7, 8, or even 9-inch pots early in May, and though
this means work, and requires a large amount of potting soil, it is the only
thing to do if success is to be obtained. After this, there will be no cause for
anxiety if care be given to airing, watering, and protecting from frost, until
planting out time arrives, but this and future stages will be dealt with in
other chapters.
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MANURING, WATERING, LIFTING AND STORING.
BY S. MORTIMER.
Manuring.—in writing this brief article I propose to classify the various
sections of the Dahlia under three headings:—
(1) Show and Fancies; (2) Cactus and Singles; (3) Pompons; according to the
treatment which they require as regards manuring. The Show and Fancy kinds
require a much more generous treatment in this respect than do the other
sections. Soils vary very much according to the district, but I have not yet
seen the place where Dahlias will not thrive if treated properly. In preparing
the Dahlia quarter, I find a heavy dressing of farmyard manure) at the rate of
about 20 tons to the acre, is a very good proportion.
Commencing operations in
the course of the winter, during favourable weather, this should be spread
evenly over the surface, after which the land should be well trenched, the
manure being" mixed with the soil as the work proceeds. In the month of March or
April, I mark out, my bed for the Show and Fancy Dahlias, in rows, 4 feet apart
each way. I then dig holes which will hold about three or four spades of rotten
manure, replacing sufficient of the soil taken out to plant the Dahlia in
without disturbing the manure underneath. Thus, as they commence growing, they
get a good start, which is very essential if good exhibition blooms are required
', I also find it an excellent plan to go over them once or twice when growing,
and throw a handful or two of soot round each plant. This should be done on a
damp day, if possible.
For Cactus and Single Dahlias the land should be prepared in a somewhat similar
way, but not quite so freely manured. It is not necessary to place manure under
each plant, in fact, very good results may be obtained with these types when
grown in any ordinary garden soil, but- to obtain good exhibition blooms they
must have a rather rich ground.
Pompon Dahlias are grown for their profusion of small globular flowers. The
smaller and more compact they are the closer they approach the ideal after which
we are striving. Consequently Pompons require very little manure, or they tend
to become large and coarse. The best quarter for them is on land that has been
manured the previous year for some other section. Some of the very best Pompon
Dahlias can be grown on rather poor land, provided that they are kept
well-watered.
Watering.—The Dahlia is naturally a moisture-loving plant, and the large fleshy
stems and leaves require a great deal to support them. They will flower very
freely if left to themselves without much water, but under these conditions, a
great many of the blooms would be thin and open-eyed. Some of the best varieties
of the Shows, Fancies, and Pompons will often come with a hard green eye if they
do not get plenty of water when developing.
When Dahlias are in full growth, and it is a hot, dry season, they should have
an abundant supply, at least three times per week. It is a very great mistake to
just throw a little water round them occasionally they must have a thorough
root-soaking, as if they once get a dry soil round the roots there is no chance
of getting exhibition blooms. I do not advocate giving liquid manure to Dahlias,
as I find it has a tendency to make the flowers large-petalled and coarse. Given
fairly good ground, and plenty of water, they do not require liquid manure.
Lifting and Storing;.—Before lifting the roots in the autumn, they may be
allowed to remain until touched by frost, or if the coming of the latter be
delayed too long, it is a good plan to cut off the tops and place them over the
roots for a few days, as protection in case of sudden frost. Choosing a fine dry
day for lifting, shake some of the soil from the roots, not all, as some do, and
after turning upside down to pour out any water that may have accumulated in the
hollow stem, place the roots in an airy position to dry off the moisture.
Those -who have not much room or convenience for storing may place them in a
cellar or any place away from frost; but do not on any account store them in
sand, ashes, or sawdust.
I store my own roots in the following way: Being fortunate enough to have plenty
of greenhouse room, I place an open trellis of woodwork over the floor of the
house, and as the plants are lifted put them at once close together m a single
layer over the trellis, where they remain in excellent preservation until
required for propagation or planting out.
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THE ENEMIES OF THE DAHLIA, AND HOW TO DEAL WITH THEM.
BY H. L. BROUSSON.
A DAHLIA plant has a good many enemies to contend with during its short life,
but it is easy to keep them under control provided the cultivator is willing to
devote a little time and trouble to the task. I now propose to show how all
these enemies may be entirely destroyed, or at least held in check, so that the
plants and blooms will suffer little, if any, damage, and the grower can carry
out the directions which I give, in whole or in part, according to the purpose
for which the plants are required. There will not be many who have sufficient
enthusiasm to make the night visits to their plants which I feel bound to
recommend as the most effective and time-saving remedy. It is unnecessary for
most growers to so sacrifice themselves, as it. is of very little consequence to
the majority if a few earwigs are left to attack the plants, but the
enthusiastic exhibitor will have no hesitation in making use of the quickest and
most certain means of destruction. It is not exactly" a congenial task to be
examining" Dahlias in the garden at night time, but it is the most effective way
of destroying earwigs, slugs, and caterpillars, their three most destructive
enemies.
Prevention is better than cure, and something can be done before the young
Dahlias are planted out. The pests mentioned feed on the young growth of almost
any plant or weed, and it is advisable, therefore, to keep the proposed Dahlia
bed and surrounding ground free from weeds. Earwigs in particular are very fond
of unused corners of the garden, and collect in places where they are
undisturbed. A hedge will harbour slugs, and if it exists near the Dahlias it
certainly is a source of danger, particularly in damp seasons. Sonic lime or
soot should be spread on the ground between the Dahlia and the hedge, as both
slugs and caterpillars will find it difficult to- cross this barrier. A watch
should he kept on neighbouring fruit trees and plants, for should they be
attacked by green or black fly the Dahlias will probably suffer in the same way.
Wire-worms, if they exist in quantities, may do a great deal of damage to the
roots. But this is only likely to be the case if the soil is pasture land which
has recently been brought into cultivation. As a remedy some carrots should be
sunk in the ground to a depth of four or five inches, and examined every two or
three days, and especially when the soil is moist. If there are many wireworms,
they will be discovered clinging to the carrots, or lodged in the little holes
which they have bored.
The principal enemies of the Dahlia are earwigs, slugs, caterpillars, green and
black fly, thrip, frog-hoppers, and ants.
Earwigs.—The presence of earwigs is recognised by the holes they make in the
leaves of the plants and petals of the flowers, and by discoloration of the
buds. The well-know way of trapping these destructive insects is by means of
small flower-pots placed on the stakes of the plants, and filled with straw or
some similar material, such as cotton-wool, which is infinitely preferable. The
pots should be examined every morning, and many earwigs will be caught in this
way. They begin to feed on the Dahlias at dusk, and as the night becomes,
colder, many of them enter the pots for the sake of the -warmth afforded. After
daylight breaks, and the air becomes warmer, the earwigs begin to leave their
shelter, and it is therefore of the greatest importance to examine the pots
early in the morning. This is rather a lengthy task when a large number of
plants are grown, and one can make much shorter work of the enemy by trapping
him at night time.
I have already mentioned that the earwigs begin their attacks on the Dahlias as
soon as daylight has gone, and by 10 p.m. most of them -will be hard at work.
Now is the time to secure them, and this is easily done with the aid of some
form of light. It is best to use a lamp which concentrates the light on a small
space, say, an electric or acetylene lamp, but the homely candle will do. The
buds and tips of the growing shoots should be carefully looked over, and when
the plants are in bloom, it will be the flowers that are being chiefly attacked.
The earwig is particularly fond of lodging in the back petals of the older
blooms, and, in common with slugs and caterpillars shows a decided preference
for white and yellow varieties. One evening's work will almost clear the plants
of these pests for the time being, but it will be as well to examine the Dahlias
about once a week, choosing warm, dry evenings, when the whole of the earwig
world will be at work. The exhibitor should examine his plants every night for a
week before show day, leaving his old blooms on the plants as a decoy for the
earwigs, and also as a protection for the blooms which lie will require on the
great day. All buds and blooms which are likely to be of service should have
cotton-wool wound round their stems. This is not an infallible protection, but
earwigs, caterpillars, and slugs find great difficulty in crossing the barrier
thus set up. In addition, or as an alternative to the pots, short lengths of
hollow cane or wood, or old bean stalks, make very good traps, and should be
attached to the' stakes. If bamboo canes are used for stakes, the holes should
be plugged with cotton-wool or clay, to prevent, the earwigs from taking shelter
therein.
Slugs.—A ring of soot or lime should be made round each plant, and, in fact,
round the whole bed as soon as the Dahlias are planted out. As slugs work at
night, they should be picked off the plants at the same time as one is capturing
the earwigs. They will be found in the greatest numbers on warm, damp evenings.
Handfuls of bran may be sprinkled between the plants as a protection to them;
the slugs will collect on the bran in great numbers, and the task of searching
for them will be greatly simplified. The bran can be examined in the morning,
but, of course, most of the slugs will have departed by then. Earwigs and
caterpillars will also be caught in this way.
Caterpillars.—Caterpillars do not attack Dahlias much, but even a few of them
can do a great deal of damage if they are allowed to pursue their ravages
unchecked. Those which attack the Dahlias are nearly all of a greenish colour,
and consequently are difficult to detect among the leaves. They eat the leaves,
buds, and blooms, and must be searched for very carefully by day as well as by
night. In the daytime they "will be found on the blooms or among" the leaves,
but at night they are more easily discovered, as they are nearly sure to be
attacking the blooms and buds only. Sometimes it seems impossible to catch a.
particular caterpillar which is suspected to exist, and then endeavours should
be made to tempt it from its hiding place with young lettuce or cabbage leaves
laid amongst the foliage of the plants. The addition of a little damp bran to
the bait will make it still more certain.
Green and Black Fly,—Dahlias in their early stages are frequently attacked by
green and black fly, which is easily got rid of, provided energetic measures are
taken at once. The presence of the fly will be recognised by the crinkling of
the young leaves of the growing shoots, and, on careful examination, either
green or black fly, or both will be discovered on the under part of the leaf. It
is during the earlier stage, when the plant is chiefly making root growth, that
the fly is particularly destructive.
Later on there is not so much danger, the growth of the foliage being very rapid
after the middle of -July. The plants should be syringed with some good
insecticide, of which there are numerous preparations in the market. It is best
to use a very fine syringe, and to apply the liquid with considerable force. The
plants are very hardy, and will probably not be damaged by this application, but
as a matter of precaution it is safer to commence with half the strength
recommended by the manufacturers, and to increase gradually to three or four
times that strength if necessary. It is well to syringe the plants with clear
water a couple of hours or so after making a strong application, to ensure the
foliage against damage.
Thrip.—Fortunately, thrips very rarely attack Dahlias. The thrip is a very small
black insect with rather a long body. It has the effect of blanching the leaves
and buds. The remedy is sponging the leaves and stems with a strong solution of
insecticide. If after a fair trial it is found that the thrips cannot be kept
under, it is better to root up the particular plant infected, lest the adjacent
ones be attacked by the pest.
Frog-hopper,— Fortunately these insects are not very common, except in certain
districts and seasons, and many growers will not meet with them at all.
Unless the frog-hoppers are on the plants in numbers, the damage caused by them
is scarcely noticeable. They make little pin holes in the flower stalks and
portions, of the branches just. below the bloom or bud, causing a series of
small swellings.
If any particular branch is badly injured, a good deal of its strength will
have. been taken away, and it should be cut off. The insect is about the size of
a house fly, and is of a greyish or blackish colour, but in appearance it is
like a small moth. In the spring and early summer it appears as "cuckoo-spit,"
and can then be easily destroyed. Later on, when it becomes the perfect insect,
it is not so easy to secure, as it jumps away directly it is touched, but it can
be caught if completely surrounded with the hands.
Ants.—Ants very often make their nests round Dahlia plants. Some growers
maintain that these insects do damage to the stems of the plants, and check the
growth, but personally I do not think this is the case, unless the ants are
present in large numbers. They are very easily destroyed by pouring boiling
water over the nests, but, should they be close to the plants, one cannot make
use of this remedy on account of the danger of injury to the roots, and the
nests must then be syringed with a very strong solution of insecticide.
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THE RAISING OF SEEDLINGS.
By J. T. WEST.
The enthusiastic amateur gardener growing any flower as a speciality must,
before very long, become a raiser of new varieties from seed. There is a
peculiar satisfaction about having something that our neighbour has not, and it
can only be obtained by raising seedlings. Perhaps, of all flowers that can be
raised from seed, the Dahlia affords most excitement, tempered by some joys, and
many sorrows.
Raising seedling Dahlias is not so difficult as some think. The chief obstacle
is getting the seed; once that is obtained we are on the high road to success.
Good seed cannot be bought (unless at quite prohibitive rates), and bad seed is
not worth sowing, for disappointment is inevitable. To save Dahlia seed, great
thought and constant care are necessary; it is not enough to go over the plants
about the end of September or October and pick off the pods believing them to be
full of seed, when, as a matter of fact, they may not contain even one.
Many of the best varieties produce very small and few pods (they damp off); and
good seed in even less quantity. This is especially the case with the Cactus
varieties, which have a way of producing seed at the base of the florets. Many
raisers think that from the seeds produced in this way the most refined flowers
are obtained, but generally the little that is formed is found at the apex of
the pod, where the flower becomes single or open-eyed. Here seed will be found
which is long, narrow", and possibly very weak; this must be taken great care
of. Some raisers say that their seedlings are obtained after very careful
hybridisation and scientific treatment. It may be so, but my experience does not
support their view I will not attempt to discourage any amateur, but say that,
in my opinion, we are all in the hands of fickle fortune. I have seen thousands
of seedlings raised, and perhaps not one worth looking at. On another occasion,
perhaps, from a score the raiser may be fortunate enough to secure a couple of
good ones. If one can devote a house to save seed in, perhaps there may be
something in hybridisation, but the Dahlia grown out-of-doors, does not lend
itself to cross fertilisation. To produce seed successfully it is necessary that
all the florets should drop easily, but when the weather is dry, the florets
shrivel up, instead of dropping, and w-hen it is wet or dewy they fall profusely
in the open air. Now, in crossing for seed it would be necessary to cover up
completely the flowers that were fertilised in order to keep off flies, etc. The
dew is thus prevented from damping the petals, so that they cannot drop, and
even if they do, by being enclosed they lie around the neck of the flower and
rot it through. Further, in spite of every precaution, the bloom will be visited
by night-working insects, which crawl up the stems (if they do not fly) and
visit the flowers. All chance of a successful cross is thereby soon spoiled. The
thrip is one of the very worst, for it may be in the flower doing mischief, yet
practically unperceived. Amateurs can try hybridisation, but I say it will
hardly be worth the trouble, patience, and perseverance necessary to secure
success; our work as raisers must be with the Dahlia as we find it.
For a grower to be a good raiser three things are required: firstly, a high
ideal steadfastly aimed at; .secondly, room to grow seedlings a first and second
year in addition to his named varieties; thirdly, self-denial and patience. He
must retain his best blooms to produce seed instead of cutting them to beat a
rival exhibitor. The blooms that will win a prize will probably be the ones to
produce good seed. The earlier blooms have time to ripen their seed, but the
late ones very rarely, on account of frost.
We are sometimes told that first-rate novelties are obtained simply by sowing
seed—in fact, that it is very easy to raise new varieties. But according to my
experience, to obtain from the yearling bed 2 per cent. -worth keeping is good.
Unfortunately many of the most promising of these will prove to' be worthless
when tried a second year, w-while the variety that was saved to fill up an odd
corner turns out to be a very good one.
We may get one good variety out of fifty yearlings, or we may get one out of a
thousand. If we get two out of a thousand we have done very well.
As I have said, the seed is usually found at the apex of the pod, and it will be
very necessary to go over the pods frequently and see that no decaying matter is
lodging there, otherwise the whole pod may be lost. Take this precaution,
especially if the weather be wet, or a very damp atmosphere prevails.
When frost is imminent, cut all seed pods with about one foot of the stem, and
dry gradually. After some time the seeds can be taken out one by one, but do not
despair if there are but two or three seeds in a pod, and those perhaps very
light and thin, for the better varieties are generally produced from thin seeds.
After the seed is secured, put it in a tin box or glass bottle, w-here it is
safe from mice, and keep it in a cool, dry place, looking occasionally to see
that it is not going mouldy.
About March the seed can be sown in shallow boxes or pans. If placed in gentle
heat, the seedlings will begin to appear in about ten days, coming up often very
irregularly, in ones and twos, during the next month or six weeks. Remove the
larger seedlings into pots or other boxes as they grow, taking great care of the
small and late ones, for it is better to lose fifty of the largest than five of
the small ones, which are almost invariably the best.
About the end of May, plant out in rows like cabbage plants, a foot or more
apart, according to the room at disposal, giving water if the weather be very
dry. From tins time not much trouble need be taken with them, except keeping the
ground free from weeds. After about two months some will be coming into
flower—generally a rough lot. By September most will be either in flower or
coming into flower. Do not be in too great a hurry to go amongst them, to pull
up, or to mark as a promising variety, for in so doing, mistakes are apt to be
made. Some varieties do not display their true character until late in the
season. When it is necessary to go amongst them, harden your heart, and pull up
all that are not an improvement in colour, form, or petal, but -watch for all
breaks, for it is in these that the future of the Dahlia will lie. Do not be
over-burdened with a lot of varieties; choose only the best, destroying all
else; have patience, and remember that all things come to the man who can wait,
as all raisers of seedling Dahlias have to do.
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Last updated
February 02, 2005
THE GROWING WORLD OF DAHLIAS