For February, 1922 



57 



HORTICULTURE IN HOLLAND 



'T'HE "Dutch Number" issued by the Lundou Times on Deccm- 

 ■*■ ber 6, gives an admirable and complete picture of hfe in the 

 Netherlands and of the industries in which the Dutch excel. The 

 fact that the article on horticulture — under the picturesque title 

 of "The Garden of Europe" — is by Mr, Ernst H. Krelage, the 

 vice-president of the Netherlands Horticuhural Ecderation, is a 

 guarantee of its excellence, and if that article be read in con- 

 nection with others in the number on the constitution of Holland 

 and on the agriculture of the Netherlands, it becomes easy to 

 understand why horticulture in Holland has reached such an 

 important position. Four causes would appear to have con- 

 triliutcd to this result, tlie tirst, and doubtless the most important, 

 is the natural bent of the people. The addiction of Dutchmen to 

 horticultural pursuits is of no modern origin. In the middle ages, 

 as Mr. Krelage observes, they were already famous for their 

 skill in horticulture. During the fifteenth and sixteenth century, 

 migrants from the Netherlands established themselves in Den- 

 mark and in this country and engrafted on the stock of local 

 practice their specialized knowledge of horticulture. Indeed. Mr. 

 Krelage makes the interesting observation that the liorticulture 

 of Guernsey owed its origin to tlie enterprise of Dutch settlers 

 in that island. Natural proclivity and industry would thus seem 

 to constitute tlie prime cause of the success which Dutchmen 

 have achieved in the practice of horticulture. Side by side witli 

 these gifts go also those of aptitude for business and readiness in 

 combination. Second among these causes is the instinct for or 

 habit of specialization which characterizes both Dutch farmers 

 and Dutch horticulturists. This specialization is seen in the 

 localization of special forms of horticulture in special regions. 

 Centering round .Aalsmeer are the floral farms. The neighbor- 

 hood of Haarlem is famous for bulb cultivation; Beverwijk is a 

 great Strawberry growing center. Tlie provinces of north and 

 south Holland are the great ve,getable growing districts in which 

 are produced vast quantities of early potatoes, broccoli, cabbage, 

 carrots, peas, beans, etc. To this form of cultivation some 62,000 

 acres are devoted. Fruit growing", which absorbs an equal area, 

 is more generally distributed. The trees and shrub-raising indus- 

 try is carried on in such centers as Boskoop, Naarden and Ouden- 

 bosch. Specialization in distriljution, no less than in production 

 IS a characteristic of Dutch horticulture, and in illustration of this 

 fact Mr. Krelage points out that in pre-war days the cut flowers 

 of Aalsmeer, the island village near .\msterdam, were exported 

 daily not only to the British, German and other neighboring mar- 

 kets, but also so far afield as St. Petersbur.g and Constantinople. 

 The area under bulbs is about 10,000 acres, and the exports in 

 previous years reached the enormous ligures of 25.000 tons, 

 valued, according to iNIr. Krelage, at one and a half million pounds 

 sterling. The third cause of the excellence of Dutch horticulture 

 is to be traced to the excellent system of horticultural education 

 which is in vogue in Holland and the excellence of that system 

 derives to no inconsiderable extent from the curiously decentral- 

 ized constitution of the country. .-Xs a result of this large meas- 

 ure of local government the central authority does not loom too 

 large in education, but each district has the power of determining 

 the kind of horticultural education which it shall receive. As 

 consequences of this partial decentralization, local interest in hor- 

 ticultural education is stimulated and at the same time the excel- 

 lent system of State prevention of plant diseases is rendered 

 possible. Last, and by means least, among the causes which 

 have led to the great success of Dutch horticulture, is the quality 

 of the soil. Soil and climate — no less than the industry and skill 

 of the people — enable the Dutch growers to cultivate with success, 

 not only the more easily grown bulbs such as Narcissus, but also 

 such difficult subjects as the Hyacinth. As a consequence of 

 Dutch horticultural industry and of other forms of intensive 

 farming, this small country, one-ninth tlie size of Great Britain 

 and Ireland, supports a population of 212 persons per square 

 mile as compared with 144 in the United Kingdom. Without 

 mineral resources, compelled to import coal and also food-stuffs 

 for man and cattle, Holland, nevertheless, continues to maintain 

 a population larger in relation to its area than that of any other 

 country in Europe, except Belgium. Nor is the industry of the 

 Dutch content with the cultivation of the land which is already 

 available : it extends also to great schemes for reclaiming yet 

 more laud from the sea and at the present time a project is on foot 

 which, when completed, will add a new and fertile province to 

 Holland. By constructing a system of dykes in the Zuider Zee 

 it is expected that 500.000 new acres of rich loamy land will be 

 reclaimed. — The Gardeners' Chromcle (British). 



THE PRUNING OF ESPALIERS AND WALL TREES 



It is, and long has been, the practice to treat wall trees and 

 •^ espaliers in a way which cannot very well be described by 

 another word, than ''barbarous." Many operators with knives or 

 with secateurs use these implements upon the trees with which 

 they are dealing as if they were dressing a Thorn hedge. Every 



shoot is rigidly cut back to an undeviating length, and when the 

 work is completed the pruner looks complacently on the mutilated 

 trees and congratulates himself upon the neat and tidy result of 

 his attention. Neat and tidy it may be, but it is an entirely 

 unnatural process. This continual cutting is a constant fight with 

 Nature ; and when Nature is persistently curbed or checked she 

 has her own methods of exacting retribution. The continued 

 repression of any fruit-tree inevitably leads to infertility, or, at 

 least, to light and indifferent crops. It may — nay, it does — result 

 in canker and in disease. If, when there is room, this pinching 

 and pruning were dispensed with, and trees were permitted to 

 grow freely, not only would the crops be surer year by year, 

 but the productiveness of the trees would last for a longer period. 

 Regular and moderately heavy crops would balance the tree, and 

 prunings would practically cease to be necessary. No doubt at 

 times there might be occasional over-exuberant shoots, but if 

 these were taken in time and pinched back, the sap would be 

 diverted to other portions of the tree where it would be of more 

 service. Further, the act of pinching would cause the strong shoot 

 to break most likely into two, and this in itself would prevent or 

 at the least discourage grossness. 



It cannot be denied that there is a great lack of thought in the 

 method usually adopted in dealing with wall trees and espaliers. 

 .'\t first, certainly, it is not wise to let a tree, which must ulti- 

 mately be restricted to a given space, grow away too freely. 

 The Ijranches ought to be formed by degrees, and this ensures a 

 uniform number of youn,g growths — afterwards the fruit-bearing 

 spurs — along their entire length. Bare spaces among the branches 

 can never afterwards be filled — at all events, filled satisfactorily^ 

 but when spurs are too thickly disposed along the branches it 

 is quite an easy matter to reduce their numbers. Thinning the 

 spurs may, indeed, become necessary in order that those retained 

 may receive sufficient light and air. Not only so, but when spurs 

 are too thick both air and light are prevented from reaching the 

 main branches, and these require both, equally with the spurs. 



It is all very well for the advocates of close pruning to iMint 

 to the fine fruits which are produced under their system of train- 

 ing — or, rather, of pruning. Even they, however, will not deny 

 that these fine fruits are few in number, and that year in, year 

 out, their trees do not bear even these few fruits consistently. 

 It is not a matter of conjecture, but has been proved, that a tree 

 planted, say, six or eight years, and given its head, will bear 

 treble the fruit that an espalier planted at the same time and 

 rigidly pruned will do. It is one of the signs of the times that this 

 fact is now being generally recognized, and the oncoming genera- 

 tion of gardeners will, I feel sure, use the knife with more caution 

 and with greater thoughtfulness than we their predecessors have 

 done. — Gardcnins. Illustrated. 



PLANT FERTILIZATION FROM THE AIR 



THE subject of manuring crops or plants is always interesting 

 to the horticulturist, amateur or professional. Those of us 

 who can look back half a century have noted the rapid strides 

 that have been made in the science of supplying to each crop or 

 plant the exact chemical that is most needed for its growth and 

 structure, but this has hitherto always been accomplished throu,gh 

 the roots. 



Organic manure is unlikely to be superseded as a base, for it 

 supplies the humus in the soil, the disintegrated product of decom- 

 posed straw, leaves and vegetable refuse. So far chemistry has 

 not produced any synthetic equivalent for this, so that its value 

 remains unimpaired. 



The air is, we know, very rich in nitrogen, but it cannot in its 

 gaseous state be absorbed by the plant. A small portion is, by 

 the agency of rain and moisture in the air, converted into am- 

 monia in the soil and is quickly seized upon by the roots of plants. 



Carbonic acid gas, always present in our air. can be, and is, 

 absorbed and broken up above ground by the plant itself. The 

 green leaves of plants are in themselves a wonderful laboratory 

 wherein the chemical reaction takes place, the carbon being ab- 

 sorbed by and into the structure of the plant, while the oxygen- 

 is liberated, and it is of this wonderful process of collecting mate- 

 rials from the air that I wish to speak. 



The normal quantity of carbonic acid gas or carbon di-oxide 

 in the air is somewhere about 0.03 per cent, a minute (|uantity, 

 and yet if this is much exceeded the effect on animal life is dis- 

 astrous and a large quantity is absolutely fatal. It appears, how- 

 ever, from experiments that plant life will thrive and fiourish 

 luxuriantly in an atmosphere impregnated with five or six times 

 the normal quantity. 



As far back as 1902, Messrs. Brcovn and Escombe publishe<l a 

 paper giving the results of experiments in using carbonic acid 

 gas on growing plants by raisin.g the content of the carbonic acid 

 in the air of the glasshouse to ll'A parts per 10,000, but the results 

 were not satisfactory. There is no mention of the ,gas being puri- ■ 

 fied. so that impurities present in the gas would account for the 

 misleading results. 



