Kitobni o'qish: «The Book of Bulbs»

EDITOR'S NOTE

Like many another distinguished gardener, Mr Arnott is a Scotsman, being a native of Dumfries, and now living in the adjoining county of Kirkcudbright. For the last fourteen years his name has been a familiar one to readers of the leading journals devoted to gardening, for he has been a very frequent contributor to The Gardener's Chronicle, The Gardener's Magazine, The Garden, The Journal of Horticulture, and other papers. Although not a professional gardener, Mr Arnott is a practical one, for he manages at least the flower department of his beautiful garden almost without assistance; and having spent most of his life amongst flowers – his mother being a great gardener – he is a successful plant grower, as well as an interested one.

Mr Arnott takes an active part in the work of encouraging the gardening spirit among his countrymen, and is a member of the Scientific Committee of the Royal Caledonian Horticultural Society, as well as a member of other leading associations with similar aims.

CONCERNING BULBS BY THE EDITOR

Anyone who has observed ever so casually the order of flowering of the plants in garden or hedgerow, must have noticed that bulbous plants figure prominently amongst those which flower in the early months of the year. Winter Aconite, Snowdrop, Crocus, Scilla, Chionodoxa, Daffodil, Fritillary, Anemone, and Tulip are among the greatest treasures of the spring garden, and though these are not all strictly bulbous plants, they all have either bulbous, tuberous, or other enlarged form of root or underground stem which serves a like purpose. Even those early flowers, the primroses, are borne on plants whose thick, fleshy, underground parts are almost tuberous in appearance; and it will be found that all the earliest blooming plants of spring are furnished with large stores of nutriment in root or stem. Only by virtue of these granaries of materialised solar energy, accumulated during the spring and summer of the previous year, are plants able to manufacture leaves and beautiful flowers in those early months during which the sun yields little heat and light, so essential to healthy plant life.

In a sense, we may consider bulbs and tubers as functionally equivalent to seeds, for they contain within sundry wrappings a dormant plant and stores of food material, wherewith the young plant may be nourished from the time when growth commences until the plant can fend for itself.

It is easy to understand how great an advantage it may be to a plant, in which cross-fertilisation is essential to racial vigour, to open its flowers before the great armies of floral rivals expose their baits to the gaze of flying insects whose visits are desired. For a like reason, it is advantageous to certain flowers to appear late in autumn after the summer flowers have withered and the competition for insect visitors has abated. These also have usually woody stems, or bulbous or tuberous rhizomes or roots, in which are stored reserves of starch, sugar, and other foods formed in the season of sunlight. Fibrous-rooted plants, on the other hand, for the most part flower between the months of April and September, when the daily hours of sunlight are many.

We commonly speak of the bulbs of crocuses as of tulips or of onions, but morphologically there is a distinction, although functionally there is little or none. If we examine a tulip bulb, we find that it is mainly composed of thick succulent scales which closely overlap one another, in the centre being a flattish axis continuous with the roots below, and with the leaf and flower-bearing stalk above. This axis is part of the tulip's stem, the fleshy scales being morphologically but modified leaves whose basal portions have become swollen with stores of nutriment. After the tulip has flowered, it sets to work to manufacture fresh supplies of food material which is sent down the stem and there accumulated in a new bulb, formed by the development of a bud contained among the scales of the old and now withered bulb of the previous year. These stores will, in the following season, enable the tulip to cut a pretty figure before it or other plant has had time or opportunity for preparing fresh supplies by the aid of the spring-time sun alone.

The so-called bulb of the crocus has a somewhat different structure. The crocus "bulb" does not, like that of the tulip, consist of overlapping scales, but of a more or less homogeneous mass enclosed in a stiff membrane, within which may sometimes be seen two or three smaller membranes of similar structure. From the lower part of the "bulb" issue roots, and from its summit proceed the leaf-bearing and flower-bearing shoots. The crocus "bulb" is not strictly what botanists call a bulb, but is a corm (Κορμος = a stem), the expansion being composed of the swollen base of the stem and not, as with true bulbs, of the leaves – the latter having degenerated into mere membranous sheaths, which have no function beyond serving as protective envelopes for the food store and living nucleus within. As in the case of the tulip, so the crocus, having flowered in the early days of the year, proceeds to make and store up fresh supplies of starch and other food in readiness for the following year. The base of the stem enlarges above the old and withering corm, from which it sucks the remaining nutriment. Fresh roots are formed, some of which, having penetrated the soil to a varying depth, contract in length, and so draw down the new corm to the level of the old.

This contractile power of roots has another office of great interest in connection with bulbs and corms. I have said that new bulbs form around the old exhausted ones by the development of buds in the axils of the leaf scales. It is obvious that in this way overcrowding must result, and that the young bulbs must often fare badly through being obliged to seek nourishment from soil already half exhausted of the elements necessary for the plants' health. But by the development of lateral roots which subsequently contract, such bulbs are often pulled to an appreciable distance from their parent, and thus gradually by yearly steps spread over a considerable area. Kerner quotes an interesting illustration of this process. Some soil containing bulbs of Tulipa sylvestris was once put in a garden in Vienna in the middle of a grass plot shaded by maple trees. As the grass was mowed every year before the flowers opened there was no formation of seeds, and the tulips could only multiply by offshoots. After about twenty years, the lawn was covered with tulip leaves, which arose from subterranean bulbs occupying an area ten paces in diameter. Thus, in the time mentioned, the bulbs had spread for about five paces in all directions in consequence of the pull of the contracting roots.

Indeed, the underground life of bulbous plants, both during their more active stages of growth, and in those times mistakenly spoken of as the periods of rest, is full of interest to the careful observer. That curious process of ripening which is essential to the health of nearly all bulbs is itself no merely mechanical change. Each plant has its peculiar time for bursting through the surface of earth, for expanding its first leaves, and for displaying the glory of its first blooms; and any material hastening of these processes by the artificial application of heat means, except in a few species, subsequent debility to the plant, and, as a rule (though not invariably), diminished character in the flowers thus forced. There are, however, plants, such as Lilies of the Valley, to which the so-called resting stage seems of less duration and importance, and it is such flowers which may be forced under carefully arranged conditions with little ill result.

Among our English wild flowering plants, the principal ones furnished with bulbs or corms are to be found in the orders Iridaceæ, Amaryllidaceæ, and Liliaceæ. Included in the former are the very rare purplish flower known as Columna's trichonema, and the doubtfully native Crocus sativus, the autumnal saffron crocus, referred to by Hakluyt at the close of the sixteenth century: "This commodity of Saffron groweth fifty miles from Tripoli, in Syria, on an high hyll, called in those parts Gasian, so as there you may learn at that part of Tripoli the value of the pound, the goodnesse of it, and the places of the vent. But it is said that from that hyll there passeth yerely of that commodity fifteen moiles laden, and that those regions notwithstanding lacke sufficiency of that commodity. But if a vent might be found, men would in Essex (about Saffron Walden), and in Cambridgeshire, revive the trade for the benefit of the setting of the poore on worke. So would they do in Herefordshire, by Wales, where the best of all England is, in which place the soil yields the wilde Saffron commonly, which showeth the natural inclination of the same soile to the bearing of the right Saffron, if the soile be manured and that way employed."

The Amaryllis order contains the Daffodil and the Snowdrop, as well as Leucojum æstivum, which is thought by some to be a native species. It is, however, the order of the Liliaceæ to which belong the majority of English bulbous flowering plants. Bluebells, like "heavens upbreaking through the earth," purple Fritillaries, yellow Tulips, Stars of Bethlehem with curious greenish flowers, Vernal Scillas, the not-so-pretty S. autumnalis, and the Broad-leaved Garlic, whose white flowers are among the most beautiful of all, though the scent of the whole plant is very "grosse and very unpleasant for fayre ladies and tender lily rose colloured damsels which often time profereth sweet breathes before gentle wordes." There are a few other British bulbous and cormous plants scattered among the various orders, such as the Meadow-saffron which is still used in pharmacy, but the greater number are contained in the three orders named.

CHAPTER I
INTRODUCTORY

Value of Bulbs – Bulbs in Grass – Arrangement in Borders – Bulbs for Cutting – Propagating Bulbs – Diseases of Bulbs

Bulbous and Tuberous Plants

Our gardens owe so much of their charm to the free use of plants with bulbous or tuberous roots, that it is unnecessary to impress their value upon the reader. We have only to cast our thoughts upon the many flowers of this character which bloom from the dawn of the year to its close, to recognise their almost transcendent claims upon our notice. In the following pages an attempt has been made to assist those who wish to know something more than they have done about these plants. Much more could have been said, but the scope of the work would not permit of exhaustive details. In addition, however, to the information given in the chapters dealing with the various plants, it is desirable that a few general hints should be given regarding the uses of these plants, and how they may be turned to most account.

Bulbs in the Grass

One of the most delightful phases of bulb-growing is that of the cultivation of hardy species in the grass. Nowhere do they look so well as against the grass, whose leafage seems to harmonise so well with the general character of the bulbous plants. In addition to this, many of these bulbous plants will thrive much better in grass than in a cultivated border, where there is often too much bare soil, and where other flowers of encroaching nature can injure them. Nearly all hardy bulbs do well in grass if the place is properly prepared for them by removing a portion of the turf, forking up the earth beneath, and adding fresh soil when it is too poor, and then replacing the turf. One thing must be remembered as a sine-qua-non, and this is, that on no account must the grass be cut until the plants have ripened their leaves. This will be shown by the foliage becoming yellow. Neglect of this has been the cause of much disappointment, and it is thus advisable that the bulbs should not be planted where a neatly kept grass plot is wanted early in the year. In planting the bulbs, they ought not to be arranged in regular lines, but in masses or informal groups. As good a plan as any to follow in planting in masses in the wilder parts of the grounds, is to throw the bulbs down from the hand, and to plant them where they fall. A good lesson will be given by a glance at a long-established plantation of Snowdrops or of the wild Scilla nutans, where these will be seen to have formed charming groups and masses of greater beauty than any formal arrangement would give.

Arrangement in Borders

It is more difficult to arrange bulbs in borders in pleasing ways, and in such a manner as to harmonise or contrast in colouring with other flowers in bloom at the same time. One desirable way is not to keep all the early flowering bulbs near the front of the border, as one would naturally do, because of their dwarf habit, but to plant them so as to give balance in the border at the different seasons. Bulbous plants, like most others, look better in groups than scattered singly in lines, and it is wiser, as a rule, to plant a clump of one kind than a mixed mass. One exception, at least, is in the Montbretias, which, when mixed, look even prettier than in separate groups of one shade. Colour arrangement is always a troublesome question in planting these flowers, and there is more satisfaction, if harmony instead of sharp contrast is aimed at, by arranging, say, different shades of yellow together, than in working to secure strong contrasting effects. Such a contrast as the white Galtonia candicans and Gladiolus brenchleyensis is striking at the time, but it is not one on which the eye would love to dwell from day to day and from hour to hour.

Bulbs for Cutting

These plants afford an almost endless choice for cutting purposes, although some cannot be cut of great length of stem without destroying the strength of the bulb for another year. The flowers are generally best when cut before quite open, and such flowers will usually open perfectly in water, and will last much longer than if pulled when fully expanded. Where many flowers are used, it is better to grow a stock in the reserve garden or in an out-of-the-way border, to avoid destroying the beauty of the more conspicuous parts of the garden.

Propagating Bulbs

The greater number of bulbs are propagated by offsets, produced from the old bulbs, and which are best removed when the foliage has died down. Named Hyacinths are increased by cutting across the base of the bulbs, or scooping out the interior, afterwards allowing the wounds to callous partially. Young bulbs are produced at the wounded parts. Raising bulbs from seeds, although slow, is very interesting work, and ought to be more largely followed for the purpose of obtaining new varieties. Seeds are sown in the ordinary way in pans, and the young bulbs grown on until they attain flowering size, generally from two to five years, according to the genus and the treatment they receive. Liliums are also propagated by scales of the bulbs, inserted in pots or pans, with a portion of the base attached. These will eventually form little bulbs, to be grown on as in the case of seedlings. Tuberous-rooted plants, like the Anemone, are propagated by division of the tubers.

Diseases of Bulbs

These plants are subject to a variety of diseases, such as always appear among plants grown in large numbers together. The leading genera, such as the Lilium, the Iris, the Gladiolus, or the Hyacinth, are all affected, and although many remedies have been tried it is difficult to find a cure. I find Veltha gives good results, but where the disease cannot be exterminated by such means it is better to destroy all affected plants, and to give the others fresh soil. A surface dressing of new soil with a little kainit added is beneficial.

CHAPTER II
HARDY BULBS

Aconitums – Alliums – Alstrœmerias – Anemones

Aconitums

Although the effective Aconitums or Monkshoods of our gardens are usually classed with ordinary herbaceous plants, the best of those with tuberous roots can hardly be omitted from this work. They are of much service in the mixed border or the wild garden, and it is only the poisonous properties of these plants which make one view them with suspicion. They should not be planted where any danger can result to children or to animals. Their nomenclature is very confused but the names below are authoritative. The following are some of the best: – Cammarum, four feet, purple; flaccidum, six feet, violet; heterophyllum, two feet, yellow and blue; japonicum, six feet, flesh; Lycoctonum, a pretty yellow species, four to six feet high; Napellus, very poisonous, in several varieties, four to six feet; paniculatum, three feet; and variegatum, three to six feet, blue, white, or blue and white. All of these grow in any soil and can be planted in spring or autumn.

Alliums

The Alliums can hardly be classed as among the choicest of bulbous plants; but although not among the élite of our garden flowers, there are, however, among them some pleasing and useful flowers, and a few remarks upon some of those most easily obtainable may be of service. It may be premised that the Alliums are most suitable for naturalising in grass or in wild gardens, as many of them are so prolific that they are apt to become troublesome in the border. They usually seed very freely and some produce offsets in great numbers, while others, again, form little bulbils on their heads which eventually form separate individuals. Almost all are of easy cultivation, although some of the Central Asian and Californian species need a little protection in winter.

A. acuminatum is a pretty dwarf species with deep rose flowers, and other pretty dwarf forms or species of similar or deeper colour are Bidwilliæ, Breweri, falcifolium, Fetisowii, macnabianum, narcissiflorum, ostrowskianum, and pedemontanum. A few blue species exist and are generally very pretty, though sometimes tender; of these, cæruleum, cyaneum, kansuense, and violaceum may be mentioned. A great many have white flowers and it is among these that we find the most valued of the species. The greatest favourite is neapolitanum, so much used for forcing, and which is grown in pots under the same treatment as other bulbous plants. Other pretty white species are triquetrum, subvillosum, Erdelii, and falciforme. None of the yellow species are equal to the old A. Moly, a bright June flower, but others of worth in their own way are flavum, and the straw-coloured stramineum. Good tall species, some having ornamental foliage, are karataviense, giganteum, sphærocephalum, nigrum, Suworowi, and nobile. The great drawback of the Alliums is their odour, which is, however, not always perceptible except when the flowers are cut.

Alstrœmerias

There are few finer or more useful garden flowers than the Alstrœmerias, whose brilliant colours and uncommon forms are great attractions. As cut flowers they are highly prized. They like a free root run, and a rather light, rich soil. The tubers should be planted in spring, nearly a foot deep, but they are easily raised from seeds sown in gentle heat in spring. Several of the species are too tender for outdoor cultivation everywhere, the hardiest being A. aurantiaca, which has yellow flowers of varying shades. Chilensis and peruviana, or versicolor, and psittacina of gardens (syn. pulchella), are all fairly hardy, psittacina possessing a singular combination of crimson and green colouring. A. pelegrina and its variety alba are exceedingly beautiful, but require frame treatment except in the south. Diazii, Ligtu, and hæmantha (syn. Simsii) are very beautiful and more or less hardy according to the climate and soil. Some lime rubbish is often useful mixed with the soil, together with a little peat or leaf-mould.

Anemones

The tuberous-rooted Anemones, which alone come under the scope of this work, form a section which embraces flowers of surpassing beauty. Generally dwarf in stature, these Windflowers give us much variety of colouring, from the pure white of A. nemorosa to the deep scarlet of A. fulgens, with the blues, purples, and other tints of A. coronaria, and the bright yellow of A. ranunculoides. Usually of easy cultivation, they are among the choicest ornaments of our gardens.

A. apennina, the Apennine Windflower, is a delightful little plant, growing about six inches high and having pretty blue flowers. There are white and rose-coloured varieties. It likes a peaty soil, and prefers shade. It is a charming plant to naturalise in the woods, where it flowers in March and April.

A. baldensis, the Mount Baldo Windflower, is of erect but dwarf habit, and grows about six inches high. It has little white flowers tinged with blue or red, and does well on a rockery in half-shade in sand and peat.

A. blanda, the Fair, or Greek Windflower, is one of the earliest of our flowers in sunny gardens, and frequently opens soon after New Year's Day. It needs a well-drained, warm position, but flowers better on a stiffish soil.

There are several forms of this very beautiful Windflower. That called cypriana has flowers which vary from white to lilac and pale blue, and the variety taurica has blooms which embrace an even deeper blue among its shades. The variety scythinica is one of the choicest. The exterior of the flower is blue, while the inside is pure white. The seeds of A. blanda should be sown as soon as ripe.

A. caroliniana, a North American Anemone, now referred to heterophylla, grows about nine inches high, and has finely cut leaves and white or purplish flowers in May. It likes a shady place and peaty soil.

A. coronaria is the well-known Poppy or Crown Anemone, which is so wonderfully varied in its form and colouring. We have no more effective flower than this in beds or lines in May. For cutting, its blooms are most useful. This Anemone is best propagated from seed annually. It likes a rich, light soil, and cow manure is the best to apply to it. The "St Brigid" strain is a charming one, and the flowers it produces are of great beauty. Tubers of A. coronaria of excellent quality can be purchased at a very low price, and should be planted in a sunny position about three inches deep in October or November. Seeds should be sown in March or April, and should be mixed with dry soil or sand to separate them. The double Crown Anemones are very beautiful, although not so much grown as when they were favourite florists' flowers. They are of almost every colour but yellow. A good white is named "The Bride."

A. fischeriana, a Siberian plant, grows about six inches high, and has white flowers. A. intermedia is a new Anemone with yellowish flowers, and seems allied to nemorosa.

A. nemorosa, our native Windflower, gives us several lovely forms. The double form, A. n. flore-pleno, is very beautiful, and there are a few large-flowered forms, besides the pretty bracteata, which has ruff-like green bracts round the flower. The variety rosea and its double form have rosy flowers, and cærulea has pretty blue blooms, but is surpassed by the charming robinsoniana of a brighter blue. Alleni is even larger and better coloured than the last-named. All these like shade and peaty soil.

A. palmata is a lovely little plant, which grows from six to nine inches high, and has yellow flowers. There is a white variety, and a very rare double one. It likes a moist, peaty soil.

A. ranunculoides is a pretty little native species of the nemorosa type, but with smaller yellow flowers. The variety pallida, with pale yellow blooms, is very pretty.

A. stellata, or hortensis, is a pretty southern Anemone which is not so good in cold districts as A. coronaria, although pretty and varied in its colouring. It likes a warm soil and sunny position. There are pretty "Chrysanthemum-flowered" double varieties, and a double red, different from fulgens fl. pl., which blooms pretty well, even where the other forms do not succeed. All of these may be grown from seed or by division of the tuber before planting.

A. fulgens is a popular Anemone, because of the beauty of its brilliant scarlet flowers. It is, however, difficult to induce to flower after the first year, and it ought to have a warm place, where the tubers will get well ripened after they flower. There is a double form, and a recent re-introduction, bicolor, has its blooms scarlet and white in stripes. Aldboroensis and græca are good forms.