FoT August, 1921 



679 



unaceoimtablL' to the owmr, but vvlicii facts arc elicited tlic solu- 

 tion of the problem is not dilticuU — they die from want of mois- 

 ture at the roots. Azaleas are potted for the most part in peat, 

 and when they are watered, unless it is done thoroughly, little, if 

 any, moisture percolates to tlie ball of roots, and through lack 

 of this a shrinkage soon takes place, lea\es drop off, and a gen- 

 eral collapse follows. On the other hand, ferns of a delicate 

 nature, which have been grown for market in a house where the 

 air is charged with moisture, when they are removed to new en- 

 vironments which are drier are frequently given too much water 

 at the roots. Plants in a sunny window need to be watched, and 

 subjects like Heliotropes, Fuchsias, and Zonal Pelargoniums 

 watered with discrimination. The golden rule of the "happy 

 medium" is the best guide one can follow in watering plants in 

 pots. 



Stimul.\nts. — When pots are full of roots a period arrives 

 when it is seen that the plants need something more than clear 

 water. It is then when a weak stimulant is beneficial, but no 

 stimulant should be applied as a substitute foi the usual water. 

 Stimulants ought not to be given plants in a dry condition. As 

 everyone knows, there are many concentrated manures on the 

 market that, administered according to directions, are safe and 

 do for plants what it is claimed they will but the virtue of old 

 soot ought not to be overlooked. — Ganlcii llliistiiitcd. 



SOME EFFECTS OF DROUGHT UPON EVERGREENS 



For a long time I had been puzzled by what appeared to be the 

 ravages of some caterpillar among Rhododendron and other 

 evergreens. The leaves appeared to have had holes punched out 

 of them either at the edges or between the latter and the midrib. 

 Many experts declared these clean-cut bites to be the work of 

 caterpillars, but no creature of that description could I ever dis- 

 cover either by night or day. Then my doubt of the caterpillar 

 theory was strengthened when the discovery was made that the 

 leaves of a CamrlUa Donckclaari (in the open) were being 

 treated in the same wa\'. Earwigs and woodlice were suspected, 

 of course, but I could never find either one or the other. I be- 

 lieve the fundamental cause to be drought, not necessarily root 

 dryness alone, but excessive leaf evaporation. The shrub, feeling 

 that it is subjected to more dryness than it can comfortably with- 

 stand, cuts out some of its leaf areas, and by so doing endeavors 

 to check evaporation and so restore that nice adjustment which 

 must exist between absorption and respiration in the economic 

 w'ell being of a healthy shrub. It is well known how Rhododen- 

 drons, especially some Hiinalayans, droop their leaves when sub- 

 jected to a parching east wind so as to retard evaporation. Here 

 on my dry bank, I have noticed that these shrubs not only part 

 with portions of their leafage, so as to give what remains a 

 better chance of survival, but they often form lines of cork cells 

 parallel to the midrib of the leaves. This causes the latter to 

 curl inwards, as well as to droop, and it seems probable that this 

 action is but a phase of the same phenomenon, another style in 

 self-preservation. 



These facts and assumptions naturally open a wide field for 

 thought on the subject of evaporation in evergreens, and I can- 

 not help thinking that it is one to which the average gardener 

 pays insufficient attention, more especially as regards newly 

 planted shrubs. Why, for instance, do Hollies so often die if 

 planted in Winter? Because the evaporation at their leaf pores 

 is greater than their pow-ers of absorption. Yet by cutting back 

 that Holly — if you catch it at the right time — it will often break 

 out. This because you have disposed of the leaf surface which 

 was exhausting the plant and at the same time conserved and 

 stimulated sap energj- by concentrating it to a given limited area 

 instead of allowing it to be dissipated feebly over the whole of 

 the branches. It is the same with many conifers which, because 

 they cannot be cut back, arc, or should be, planted in Spring, when 

 they are just breaking into activity and conditions are most 

 genial. 



There arc evergreens, notably Elaagnuses, many Ericas, coni- 

 fers and some Kalmias. which, when just planted, will endeavor 

 to rectify matters by drojiping a number of their leaves while 

 perfectly green, this again, one may presume, being but another 

 mode of that self-preservation above mentioned. But the Hollv 

 cannot part with its leaves nor the Broom with its branches which 

 serve as leaves, hence their slow and miserable death unless the 

 surgical knife of the gardener comes to their aid. If these bard- 

 Icavcd evergreens were able to drop their folia.ge when trans- 

 planted or during hot suiishiuc. with the cunning of a Cabbage all 

 might be well. But too often they are helpless. With no means 

 of checking the evaporation which is gradually destroying them, 

 with no damp "ball of soil" to balance that dissipation, they are 

 in most instances bound to succumb. 



Of course, we know what the moral of all this is. vie, "a good 

 ball of soil," frequent waterings in Summer, and so on. But I 

 rather think that if the average amateur were to realize the why 

 and the wherefore of these things he might often avoid disap- 

 pointment and loss. — The Garden. 



LIME AND THE BEARDED IRIS 



At the Iris Conference points relating to the successful culti- 

 vation of the Bearded Irises came under discussion. It is well 

 known that lime is essential to the well-being of these Irises. 

 Practically all the species are found growing on limestone forma- 

 tions. It was pointed out that the bacteria which are responsible 

 for the rot disease of the rhizomes multiply amazingly in lime 

 and consequently if there is evidence of this trouble ordinary 

 lime should not he supplied to tlic surface of the beds. Super- 

 phosphate of lime, on the other hand, is fatal to these bac- 

 leria, and a top-dressing w'ill generally stop the mischief. If 

 the plants are Iradly attacked it is recommended that they should 

 be taken up, all the affected parts cut right away the cut por- 

 tions being rubbed with superphosphate, and the plants given a 

 fresh site. Irises will not flourish in a waterlogged position. If 

 the soil is heavy the beds should be elevated above the normal 

 level or even thrown up in banks so that efficient drainage is se- 

 cured. The best time for planting is shortly after Howering, July 

 perhaps being the safest month, as new roots are then being 

 emitted. The plants are thus able to take firm hold of their new 

 quarters before Winter. — The Garden. 



COLLARETTE DAHLIAS FROM AN AMATEUR'S 

 POINT OF VIEW 



My experience as an amateur grower of Collarette varieties may 

 be useful to others. Having grown all types of the flower with 

 the exception of the giant Psony-fiowered varieties, which I con- 

 sider only useful for mixing with shrubs and such-like tall flow- 

 ering plants, I have come to the conclusion that, for the grower 

 with limited space, there is no type which will give greater satis- 

 faction than tlie Collarette section. I have grown Cactus, Single, 

 Pompon and Star Dahlias by the side of these, but without ex- 

 ception visitors have voted the Collarette the best. A vase of 

 these Dahlias with varied tints is much to be preferred to the 

 Cactus varieties, which are in bloom for a few weeks, giving ex- 

 hibition flowers and afterwards producing undersized, misshapen 

 flowers. 



In diversity of coloring and formation the Collarette Dahlia is 

 pre-eminent. Thin the foliage well, and blooms may be cut, as I 

 have done until well into October, the plants at all times being 

 well covered with flowers. For garden decoration, do not disbud 

 the flowers, but allow them to develop naturally without allowing 

 too much leaf and stem grow-th. The plan I adopt is to shield 

 the plants from the cold north-east winds, and I also erect a screen 

 to tone down the mid-day sun, as I find this is liable to bleach 

 the red tints and also causes more work with the water-can. In 

 order to do this I grow a row- of runner Beans on the south side, 

 and am fortunate in having a tall Privet hedge to break the wind. 

 I only allow a space of three feet between each plant, and place 

 stakes in readiness a month before the plants are set out. — The 

 Gardeners' Chronicle (British). 



CONSERVATION OF PLANT FOOD IN THE SOIL 



(Continued from- page 677) 

 a,gain in the Spring. There is practically no loss of plant food 

 in frozen ground even if it is bare. The portion spaded under 

 in the Spring should be used for the later sowings. 



In addition to using up available plant food and gathering 

 nitrogen, cover crops when spaded in and decomposed increase 

 the organic matter of the soil and to that extent only, take the 

 place of stable manure. 



From w-hat has been said it will be obvious that after a cover- 

 crop has been grown the amount of aviiilable i)lant food existing 

 in the soil is less, as being taken up by the crop it now exists 

 in a state of unavailability and is not therefore subject to the 

 action of leaching. This condition, however, is only temporary 

 as when the crop has become decomposed and turned into humus 

 the plant food again becomes available. 



Altogether, therefore, the spading into the soil of green crops 

 is in many directions of great value, and this, otherwise known 

 as "green manuring" is the cheapest and quickest method o» 

 changing a poor soil into a rich one, and the process may be 

 carried out during any part of the .growing season. If one has 

 a poor, thin soil it will pay to use some additional plant food 

 before sow'in.g the cover-crop, for which puriiose sheep manure 

 will be satisfactory. Should the soil require lime, it and Iwne 

 meal mav be raked in with the seed, in the latter case the sheep 

 manure should be omitted. The addition of those fertilizers 

 will cause the cover crop to grow- quicker and nfore bulky. 



In connection with groimd which has been cropped and culti- 

 vated durin.g the Summer, spading is not necessary to prepare 

 the soil for a cover crop, in fact it is undesirable as the too 

 few inches is invariably the richest especiallv in nitrogen and 

 spading would bury this out of the reach of the cover crop, 

 especially during its early stages and w-ould also facilitate the 

 leaching of available plant food into the subsoil. .Ml that is 

 necessary is to loosen up the soil well with a hoe. 



