The Amateur's Greenhouse and Conservatory/Chapter 8
THE PELARGONIUM OR GERANIUM.
In making choice of a name for any of our friends that we have been accustomed to speak of as geraniums take care to look about you. If there are any botanists within hearing, say “pelargonium,” and take all the consequences. But if none of those exacting and fastidious gentry are in the field, speak of the plants as “geraniums,” and you will have the good fortune to be understood by the entire audience without a single exception. Botanists apply the term pelargonium to that section of the great family of cranes’-bills which have irregular or unsymmetrical corollas; those that have regular corollas being by them called geraniums. Thus, all our exhibition and bedding plants that are commonly known as geraniums, are classed by botanists as Pelargoniums because the top petals are larger than the others, and the flowers are, therefore, irregular or unsymmetrical.
The pelargoniums may be divided into two great sections. The first of these have leaves wrinkled and notched, and large flowers which are sometimes brilliantly self-coloured and in other cases are blotched or striped, or delicately edged with colour. These used to be called “pelargoniums” by the florist, and the term was a convenient one to distinguish them from those of the second section. These have leaves less wrinkled than those of the first section, and a considerable number have leaves that are nearly smooth and more or less round and flat, and a very large proportion have the leaves marked with a black or brown or red “zone.” These are the “horseshoe geraniums” of days gone by, the “zonals” of modern garden phraseology, and the “geraniums” of all mankind save and except the botanists. Each of these sections may be again subdivided. In the first we shall find “show,” “fancy,” “spotted,” and “forcing” pelargoniums. In the second we shall find “scarlet,” “nosegay,” “tricolor,” and “variegated” geraniums. It is fortunate for the writer that the reader will not need elaborate explanations, for to classify and define at length the whole of the garden pelargoniums would consume time and space that both writer and reader would prefer to occupy with matters of a more strictly practical nature.
As to pelargoniums in general, it must be observed that their popularity is due alike to their brilliant and various colours both of leaf and flower, and their wonderful adaptation to the circumstances which influence the selection and cultivation of exotic plants in this country. Our summer sunshine is sufficiently fierce for them; and although our winters are always too wet and usually too cold, the most commonplace means of protection suffice for their preservation. They are most easily multiplied by means of either seeds or cuttings; they grow rapidly and flower freely, and altogether require less care and make more show than any other plants that properly belong to the greenhouse and the garden. The different groups of fancies, zonals, tricolors, and the rest, require different management, but all agree in loving light; all are adapted for pot culture; and the greater part of them thrive in a comparatively poor soil and a dry atmosphere. During winter dryness is quite as important as warmth for their preservation; for, indeed, when kept cool, dry, and well aired, they will suffer but little if the thermometer in the house should descend to 27° Fahr.; in other words, they will endure five degrees of frost, but they should never be intentionally subjected to a temperature below 35°, and an average of 40° is safer for their winter keeping.
Large Flowerwing or Show Pelargoniums.—These are the aristocracy of the race, and until quite lately, they were the most attractive subjects presented at flower-shows in the months of May and June. They are worthy the best care of the amateur because of their fine decorative properties and variety of colours. The cultivation may be commenced at any season, but the best time is the beginning of the year, and neat young nursery plants are the best to begin with. If when they come to hand, they are nicely rooted, shift them into a larger size, if, however, they are not well rooted, defer the repotting for a month. In either case they should be placed in a light and airy position in the greenhouse, and be watered cautiously. A fortnight or so after they have been repotted pinch out the points of the young shoots to promote the formation of bushy
specimens, and when it becomes necessary train out the side-shoots by means of neat sticks. Those intended for exhibition must have the branches brought close down to the rim of the pot, and be kept down as much as possible during the first year; but the growth of those intended for conservatory decoration will merely require tying out to admit a free circulation of air amongst the branches, and for securing a regular well-balanced outline when they are in flower. Upright growing plants with heads of bloom about twelve or fifteen inches in diameter are the most useful for the conservatory, and therefore excessive training must be avoided.
Remove them from the house when done flowering and place the pots upon a bed of coal-ashes, and if practicable shade them for a few days to allow the wood to become slightly hardened before they are exposed to the full influence of the sun. Henceforth they must have free exposure to the weather, and in a fortnight or three weeks the wood will be matured sufficiently to allow of their being cut down. The soil should also be kept as dry as it is possible to keep it without allowing the leaves to flag. In pruning, cut back the young shoots to within two or three buds of the old wood, according to their respective positions, but the chief aim must be to ensure a symmetrical appearance. In wet seasons they should be placed in a cold frame, and the lights drawn off at all times, excepting when they are required to protect the inmates from the rain. No water must be applied to the roots from the time they are cut down until the young growth is about halt an inch in length, but they will receive much benefit from a sprinkle overhead in the afternoon of a dry hot day. When the young growth has begun to push, turn them out of the pots, remove nearly if not quite all the old soil, trim the roots slightly, and put each in a pot one or two sizes smaller than it previously occupied. Water very sparingly until they are well established in the new soil. Even then, no more water must be applied than is absolutely necessary to maintain a steady growth. Early in September remove to the greenhouse for the winter, and the only attention required to keep them in health will be to supply them with water when necessary, and to keep the foliage free from green-fly.
Some time during January of the following year, repot all that require a shift into pots two sizes larger; that is, those occupying three-inch pots should be put into the six-inch size, and those in five-inch into pots eight inches in diameter. No further shift will be required until after they have done flowering. After the end of February the young shoots will make vigorous progress, and should be tied neatly, and their points nipped out. In succeeding years, when the period of flowering will be more under the control of the cultivator, the specimens intended for flowering in May must receive their final stopping in January; for June, in March; and for July, some time towards the end of April. Those required for May must receive their final shift in October, and be placed in a temperature a few degrees higher than that required for the remaining portion of the stock. After the first season’s growth the plants should, as soon as they are well established in the pots in which they are to flower, be watered with weak liquid manure until the flowers open and with clear soft water at all other times. They winter best in a temperature ranging between 40° and 50°, according to the weather, and with just enough fire-heat to keep the frost out and the atmosphere dry.
A compost consisting of three parts sound turfy loam, and one each of well-decayed hotbed manure and leaf-mould, and half a part of sharp silver sand, will grow all the large-flowering varieties to perfection. The soil must be used in a moderately rough condition, and the loam and manure be well mixed together. The compost should, if possible, be prepared six months beforehand, by placing the manure between the layers of loam when it is stacked up in a heap, as it comes from the pasture or common.
Cuttings of well-matured wood cut up into lengths of two joints each, with a young side-shoot proceeding from the top joint, strike freely. Prepare by cutting them close under the bottom bud, and remove the lower leaf. Insert in cutting pots, prepared in the usual manner with a layer of dry sand on the top, and then place in a cold frame. Keep rather close and shade moderately during the first week or ten days, and then ventilate freely, and expose to the full sun. Pot off as soon as nicely rooted, and if they are stopped when well established and shifted into five-inch pots about a fortnight or three weeks afterwards, they will make good specimens by the following season.
The fancy varieties are more difficult to strike than the show kinds, and therefore require more care and attention, and it is as well to give them the advantage of a mild bottom-heat, if available; but the atmosphere must not be moist with steam arising from fermenting materials. Otherwise the fancies require the same treatment as the show varieties, and mav, with advantage, be located at the warmest end of the geranium-house.
Forcing Pelaegoniums are grown in great quantities for Covent Garden Market, but are generally considered by amateurs too troublesome to be worth a place in the private greenhouse. It requires some skill to do them well, but when well done they charm away the gloom of winter, and proclaim the cultivator a master of the art. As regards quality the flowers are not so fine as those of varieties flowering later in the season, but they are produced in greater abundance, and the habit is rather better. It would not be fair to compare the flowers of the two classes, for the early flowering varieties bloom so early with a proper system of management, that they should be out of bloom and removed from the conservatory by the time the later blooming kinds are ready to take their place.
It is best to begin in July with plants a year old. If you must begin with cuttings, secure them early in March, and strike them on bottom-heat, and have the young plants in separate pots in the greenhouse at the beginning of May, when they should be potted into large 60’3 and removed to a cold frame. If this plan is not suitable to your case, secure cuttings in June, and strike them under a hand-glass without heat, and make the most of the short season of growing weather that remains.
About the middle of June, or earlier, if the season is forward, those in the cold frames should be removed to a bed of coal ashes a foot in thickness, in an open sunny spot. A mere sprinkle of ashes will not suffice, for wherever a worm finds entrance, the plant will suffer by it. In the first week of July stop all the young shoots, and before the month is out shift into 48’s or 32’s, and return them to the bed of ashes. In the first week of September the stock should be brought into the greenhouse, be placed close to the glass, and have an abundance of air. Ventilate the greenhouse freely when the plants are first brought indoors in September, to lessen the change as much as possible. In a fortnight afterwards they will begin to feel at home, and, as the weather will be getting colder, less air will be necessary. Air-giving must at all times be regulated by the state of the weather outside. In dull, damp weather use a little fire-heat to admit of the ventilators being opened for a short time during the early part of the day, rather than keep them closed for fear of the house getting too cold. It is an important matter not to deprive the plants of a breath of fresh air for the sake of a few shovelfuls of firing, when air can be admitted without injury.
If carefully wintered they will flower freely from early in March until the following May, or longer, if required. They are, however, not required after the middle of the last-mentioned month for conservatory decoration, as varieties with more highly finished flowers will be coming freely into bloom. About the middle of May place the plants in a dry airy house, where they will receive just sufficient protection from frost. Early in June place them out of doors on a bed of coal-ashes to ripen the wood, and immediately that is accomplished cut the shoots back to three or four buds each, in the same manner as other varieties. Let them remain on the bed of ashes until the young shoots are about half an inch long, and then shake out, carefully prune the roots, and repot in six- or eight-inch pots, in which they will remain until the next year. When potted, they should be placed in a cold frame, and have the freest ventilation possible. The lights should only be put on in wet weather, and then they should be tilted back and front, the object being merely to protect the plants from becoming too wet at the roots. No stopping will be required after the first shoots have had the points nipped off, as these varieties have a very compact branching habit, and bushy well-shaped specimens can be obtained without excessive pinching and stopping. In September they must go to the greenhouse, and from that time receive the attention advised for the young stock the previous season.
To secure a good bloom of forced geraniums in October is easy enough, but there must be no stint of care in summer and no stint of firing in winter. Make and manage the plants, as advised above for flowering them in March. Put them in a cold frame at the end of May, and thence remove them to a bed of ashes in the open in June, pinch out the points of all the shoots the first week of July, and carefully shift them into one size larger pots in the last week of July. House them in September near the glass and give plenty of air. As the weather becomes dull and damp, start the tire gently and give air with more caution. They are not to be hard forced, but they must have no check. The temperature must average 50° by night and 60° by day, and a little air must be admitted every day, and all day, unless the weather is very bad; but it must not reach the plants until it has acquired the warmth of the house. The plants must have more water than others of the same kinds that are at rest, and as the days lengthen in spring it will be prudent to assist them with very weak manure water, but this must not be given if they are evidently robust and healthy. They should flower freely from October to May, and plants in 32-size pots should be two feet high and two feet through, and as gay as flambeaux at Christmas. There are many varieties for forcing pelargoniums in the market, but probably in our time we shall not see one to surpass, or even equal. Gauntlet for early work.
Zonals.—If we may be excused pronouncing eulogies on this important section of the great family of geraniums we will endeavour to make amends by concentrating in a few pages as much sound information on their management as pot plants as any less experienced pen would require a volume to unfold. So, good amateurs, we begin by remarking that the first step towards success is to make a good selection, for only about a tenth part of all the zonals in the trade lists are worth the trouble of pot culture. If you will have such sorts as Christine, Tom Thumb, Stella, and Indian Yellow, you will waste all your time in growing them, for good as they are when bedded out, they are quite incapable of acquiring a respectable appearance as pot plants. The achievements of cross-breeding in this branch of floriculture are truly wonderful, for not only are the finest of the newer varieties characterised by flowers of great size, of a perfectly circular outline, the petals of which overlap, so as to produce a solid disk; but the inequality of the petals has been abolished, and they rebuke and confound the botanists by presenting symmetrical flowers on plants that are designated pelargoniums. With such fine varieties as Sir Charles Napier, Richard Headly, Ianthe, and Mrs. Sach, the amateur may labour in hope that, in due time, he shall be repaid, if he faint not.
When zonals are to be grown into specimens, it is a good plan to plant them out the first season, and allow them one year’s growing in the open ground, to form a good foundation of stout wood. They should be put in good unmanured ground, in the full sun, and before planting them it will be well to cut them into shape, and allow them time to make a fresh start before disturbing the roots. They must not be allowed to flower, and the points of all the shoots should be pinched out when two inches long, and the last stopping should take place in the first week of August. In the first week of September take them up carefully and pot them in six-inch pots, and shut them up close for a week. Afterwards put them in a light airy part of the house; keep them rather dry all the winter; in February stop them all over, or sufficiently to promote the filling-up of gaps and uniformity of contour, and in March shift into eight-inch pots. If they are intended for conservatory decoration they need not be trimmed or tied, but if for exhibition they must be moulded to the watch-glass shape by means of sticks and wires.
A good compost for single zonals may be prepared by mixing together five parts of good turfy loam with one part each of thoroughly decayed hotbed manure, leaf mould, and sharp sand. The double zonals are so vigorous in habit, that in preparing a compost for them it will be well to omit the manure and to give them less root room than the singles, for if they acquire any degree of grossness through good living, they will have more the appearance of cabbages than geraniums, and will probably not flower sufficiently to afford excuse for likening them to cauliflowers.
To ensure a good bloom of zonals in winter, begin with young plants in three-inch pots in April. These should be the best obtainable from cuttings struck the previous autumn. Shift into six-inch pots, and put them in a cold pit and ventilate freely. In the first week of June put them in the open, on a bed of ashes or leaves, and keep them growing freely, and from time to time pinch out the points of the shoots both to promote the growth and prevent flowering. In July shift them into eight-inch pots, and return them to the bed in the open. About the 10th of August stop them all over for the last time. About the 10th of September house them near the glass, and give plenty of air. As the dull cold days approach, begin to force them, but in a very gentle manner, and you will soon have flowers in galore. The temperature should average 50° by night and 60° by day, with a rise to 65° during sunshine.
Tricolors make fine pot plants, and it is necessary to grow them if we wish to appear votaries of fashion. Those that are required for winter decoration should be planted out from the end of May to the end of August, and be carefully stopped, as requisite, to promote a dense bushy growth. After potting keep them cool and airy, and otherwise treat them as advised for the zonals that are required for winter flowering, but with extra caution as to watering. It is common enough to meet with starving bits of tricolors that have been in pots for years and incline to grow smaller rather than larger; but if they were first cut back, and then planted out from the latter part of May to the middle of June, and taken up in September, they would become respectable plants in the course of one season.
In propagating tricolors, cuttings should be taken as early in the summer as they can be obtained, as they root slowly, and must be potted early to ensure their well-doing through the winter. If propagated in quantity, a bed should be made in a cool greenhouse by mixing equal parts of sharp sand and cocoa-nut fibre refuse, as in such a mixture they root quickly and make better roots than in any other kind of compost. The amateur in tricolors must learn to bud and graft them on the stems of seedling zonals, for all of them grow more vigorously if well put on, and by judicious management handsome standard tricolors may by this practice be obtained.
It is often a matter of importance to propagate tricolors in winter as well as in summer, and this may be accomplished easily by the aid of a bed of moist sand, or a mixture of sand and cocoa-nut fibre refuse, over a tank of hot water, at the warmest end of the greenhouse. The bed should have a constant temperature of 70° to 80°, and be in the fullest daylight obtainable. If the cuttings are inserted in the usual way many of them will rot, and therefore Dr. Denny’s plan should be resorted to. This consists in first tying the cutting to a short stick, and then inserting between stick and stem another stick placed horizontally to keep the upright stick and stem apart. The upright stick is thrust down into the soil so deep that the base of the cutting barely touches the surface, as shown in the figure. The roots are thrown out from the base, and the cutting begins to make new leaves, and must then be carefully potted in sandy soil in the smallest sized thumb-pots, and the pot plunged in the bed or put on a warm shelf to encourage it to become a healthy plant. The figure (p. 139) will explain the matter if the description of the process is not quite clear.
Seedling Pelargoniums.—To raise seed is easy enough, but systematic cross-breeding is an art to be acquired by patient observation, persevering practice, and the stimulus of unfaltering hope. If there are no bad geraniums in the garden, a few seeds may be allowed to ripen on the most distinct varieties in the collection, and from these something new and good may be expected. If you have a house kept at a temperature of 50° to 60° all the winter, sow the seed in August and get the plants into small pots in time to winter them in comfortable quarters. If you have only cold pits and other rough contrivances for wintering the plants, defer sowing until February and then start the seed in a nice heat. As soon as the plants are large enough pot them in thumbs, next in 60’s and finally in 48’s. In the last-named size they should be allowed to flower, as it is waste of labour to grow specimens of plants that may prove to be worthless. As the flowers open destroy those that are manifestly bad and take cuttings of all that promise to be worthy of a second trial. By good management seedling pelargoniums will begin to flower in 100 days from the date the seed was sown.