806 



THE GARDENERS' MAGAZINE. 



October Ih, i9i2. 



from and with ooil-water^ and by its leaves 

 from the air, will not feed the plant ; they 

 are only the inateriaU which the plant u&es 

 for making the stuff it feeds on — sugar, fats, 

 albumen, and the like. A clear understand- 

 ing of this fact is essential to an appreciation 

 of the value of leaves to a plant and the part 

 the bark plays in acting as a channel for 

 the conveyance of food stuffs to the parts 

 below. 



Of course the bark does something else. 

 It is of cork, and like all efficient cork keeps 

 liquids from parsing. That is the purpose 

 of the cork. But the cork is on the outtjide 

 only. Just below is a layer of fibrous cells 

 forming strong, tough bands like bast (in- 

 deed the ba^t of Archangel mats is from this 

 part of the lime tree's bark) which 

 strengthens the stem and enables it to sup- 

 port the enormous weight of the foliage and 

 withstand the buffeting of the winter winds. 

 And there are other tissues, each with some 

 pari: to play, and among them, lying just out. 



side the delicate cambium, the tubes along 

 which the iood pa&ses. 



Anything that damages the bark then 

 causes tJie How of food down the stem to be 

 checked, and one of the most marked results 

 following an attack of canker flows from this. 

 For a tiec to \ye fruitful an abundance of 

 food is necessary — food, I mean, made by the 

 tree — not food in the sense of : 

 for that stuff* from which food is to be made 

 may easilj' be given in too great quantities, 

 but actual sugar and albumen. If then the 

 downw^ard flow of food is checked more food 

 than usual will accumulate in the branch, 

 and the branch will tend to become more 

 fruitful. How often we see the cankered 

 branches of Lord Suffield bearing heavy crops 

 of fruit, and the- reason must be evident. 

 But another result less desirable than heavy 

 fruiting flows from this bark injury. The 

 tissues below it will be deprived of food en- 

 tirely or to some degree according to the 

 extent and duration of the injury. Thus if 

 the cankered area persists the cambium 

 below will gradually cease to make new wood 

 and bark, and the roots will l^e starved. 

 Truly, if one memiber suffers all the members 

 suffer. 



It is unnecessary to describe Canker. We 

 are all too familiar with the gaping wounds 

 and cracks in bark to need descriptions, and 

 we may pass now to enquire the cause. 

 Many causes have been sxigs'ested, but 

 there is only one common to all. The one 

 actual primary cause of canker is a fungus. 

 There is doubtlesis some truth in most of 

 the suggested causes, but they are secondary, 

 not primary. K: -p the fungus away and 

 the other caur.:s would not produce canker. 



This fungus, Necteria ditissima, causes 

 canker on many different kinds of trees, such 

 as ash and beech, well as apple, and more 

 ely pear. It grows into and feeds upon 

 the tissiK\> of the liark. ultimately destroy- 

 ing them. It is a parasit-, and an unwel- 

 come and troublesome gue-t that steals from 

 its h<>>t tiic food it lias made for itself, lodges 

 itself in its host's channels of communication, 

 and final ly destroys the lodging hous-e it 

 has made use of, but not before it has sent 

 out on the wings of the wind, and on the fret 



of insects numerous little pieces of its-It. 

 which we call spores, eaeh capable of srart- 

 ing anotlier parasite of precisely the same 

 dangerous character. Some of the spores are 

 formed in little bright red fruits, easy to 

 see on the canker spots in early spring, or 

 even in the winter, but smaller than a pin's 

 head, and thus often overlooked. Each fruit 

 contains numl>ers of these tiny spores. 



Perha.ps the most imjwrtant point about 

 the habits and life of the fungus from the 

 fruit-grov.'er s point of view, is the fact tliat 

 when the spores germinate, the thread to 

 which they give rise cannot make it-, wav 

 through hfalrhy, whole bark. Only wii.-ii t he 

 bark Iia.s a Imle in it can the fungus peiii-- 

 trate into the living i'/A]> beneath, begin its 

 march of dire de-t rnetion . aiirl si art that 

 sequence of evmts which t^ulni in ;it in cb-ath 

 and d(H'av. It is one of tlu- 



gani.-<'r 



is one or t lu' gr< > u p of or- 

 wuund parasites." l]ut it 



IS ca-y for it lo nuvk-e its wav even through 

 a hoU- a^ minute as a shot' hole, or even 



smaller, and it behoves the fruit-grower to 

 prevent to the extent of his power the wound- 

 ing of his trees, or when they are wounded 

 to protect the wounds with something which 

 will encourage healing and prevent the en- 

 trance of the fungus. 



If the fungus gets in it grows and, as we 

 have said, destroys the tissues on which it 

 lives. There comes a time of rest, however, 

 and during it the tree tries, as every tree 

 tries, to repair the damage done _ by the 

 fungus by covering it over with a healing 

 layer. Unless the tree is in good health that 

 time is all too short, and before the tissue is 

 cut off and the wound healed where the para- 

 site has taken its abode, the season for tree 

 growth is past, and the season for the fungus 

 development is come. Then goes on a fight 

 between fungus and tree, the one destroy- 

 ing, the other trying to repair, and the marks 

 of the fray may be seen in any old canker 

 wound. Layer on layer of new tissue is put 

 on to be almost as quickly destroyed. It 

 is possible that sometimes the fungus threads 

 may pass along a length of stem and break 

 out in a new part of the bark not previously 

 affected, so that occasionally (when a tree is 

 affected in one part) canker may occur where 

 no wound was present previom^ly. 



How are wounds caused? They may be 

 wilful, they may be accidental^ they may be 

 due to carelessness^ they may be almost 

 natural. Pruning, especially in young trees, 

 is a necessity, and too often it is done with 

 blunt or otherwise unsuitable tools, result- 

 ing in wounds difficult to heal. Knives (and 

 nothing else ought to be used in pruning 

 apple or pear trees) cannot be too sharp. 

 Cuts cannot be too clean, but all large cuts 

 should be painted over either with Stock- 

 holm tar or lead paint. Smearing over with 

 earth is useless, and worse than useless. All 

 it does is to hide, not to protect a cut. Large 

 wounds are not as a rule necessary unless 

 trees have been neglected in their youth. 

 Among the accidental Avounds, and those 

 due to carelessness, we may put thos^e due 

 to scraping with ladders and boots, shot 

 from guus^ and so on. I have known an 

 chard almost ruined through canker gain- 

 ing an entrance into wounds made when shoot- 

 ing rabbits. Among those due to natural 

 causes, breakages by storms, wounds made 

 by frost and damage by insects aad birds, 

 may be mentioned. Of the insects none is 

 worse than the woolly aphis or American 

 blight. The sucking oi* the insects may pos- 

 sibly induce a sort of gall formation, at any 

 rate they cause wounds. The trees start to 

 heal the wounds by making large masses of 

 tender healing tissue^ into whicn the canker 

 fungus can readily penetrate. No effort* 

 should be spared to get rid of this pest, and 

 to avoid making wounds in bark that are 

 difficult to heal quickly, and if such are made 

 cleanly cut them and protect them in the 

 way I have already suggested. 



The nature of the soil seems often to have 

 something to do with canker. Indeed, some 

 have put down canker to uncongenial soil 

 surroundings entirely. Tliis is, of course, 

 wrong, but no doubt bad soil conditions are 

 a great cont ri I>uting factor, just as insects, 

 slorni>. and ^lutoting rabbits may be con- 

 tributory factors. 



It will, I think, be found that soils where 

 water cannot get away freely are those where 

 apples canker worst. The probable cause of 

 this is not only that trees in such soils suffer 

 in health from the inability of their roots 

 to breathe, but they are much more liable 

 to injury from late frosts, and the same thino- 

 applies to trees planted at the bottom ox a 

 slope. Frost may frequently damage trees 

 after the leaves begin to apr.ear in such 

 '.jtuation, and actually kill buds leavino^ 

 places where the fungus mav find an en" 

 trance, and it may at times (-ause crackino- 

 and splitting of the bark. Such situations 

 should at all costs bo avoided wlu-n plantiup- 

 IS iKMng done, and all land not well drained 

 naturally should be attended to The cost 

 ratine; h.avy, but the outlay will be repaid 

 It i> nnportant to do all one can to avoid 

 (anker in the ways suggested, but it is 

 equally important to attend to trees affected 



so as to enable them to repair their injuries 

 and check the spread of disease. The oulv 

 method is to cut out all canker wounds 

 cleanly with a sharp knife and paint the 

 wound made to protect it from further in- 

 fection. If this be done consistently and 

 pbeiventave imjeassunes adopted with intelli- 

 gence and earnestness much may be done to 

 rid our orchards of this pest. Rome trees 

 of course, are beyond repair, and these should 

 be forthwith removed and burned, along with 

 all branches so badly affected as to render it 

 doubtful whether they will recover. Main- 

 tenance of good health, careful treatment, 

 and protection of wounds are essentials of 

 suocesis. 



Some varieties appear more prone to 

 canker than others ; possibly they are more 

 prone to wounding or slower to heal, and it 

 would be well to select others. The best 

 kitchen variety, Wellington, or Dumelow 

 Seedling as it is often called, is one of them; 

 Lady Sudeley in this district is another; Lord 

 Suffield, Lord Grosvenor (in Cumberland), 

 Cellini, Ecklinville, Pott's Seedling, Warner's 

 King, King of the Pippins, and Eibston seem 

 more susceptible than others, although, as 1 

 have pointed out, their liability to attack 

 may be due to contributory causes. 



MEDAL ROSES OF 1912. 



I read with considerable interest in com- 

 mon with all rosarians interested in new 

 roses, the Eev. J. H. Pemberton's notes on 

 " The Medal Roseg of 1912," in your issue of 

 October 5 last. I naturally hesitate very 

 considerably before advancing any opinion of 

 my own that controverts any statement that 

 comes from such an authority, but it is for 

 that reason only that I write you. The opinion 

 of the President of the National Eos© So- 

 ciety na^turally carries so much weight that 

 that which he may give expression to may 

 seriously effect the reputation of a rose, at 

 any rate, for a season or so; and, although 

 he rightly prefaces his remarks by a state- 

 ment that they are merely first impressions," 

 still that statement may be lost sight of, 

 and the effect of his opinion before referred 

 to remain. 



The remarks that I desire to draw your 

 attention to occur under the reference to 

 Messrs. Alex. Dickson and Sons' new decora- 

 tive single Irish Fireflamef ((called Irish 

 Flame by Mr. Pemberton), This rose is well 

 known to me; its flowers are larger, not 

 smaller, than Irish Elegance. Mr. Pember- 

 ton goes on to say that, " from our inspection 

 of the plants at Newtownards, one is in- 

 clined to think it took a good many plants 

 to fill such a basket" (refering to the ex- 

 hibit at Southampton, which by the way, 

 was not a basket but a series of tripods or 

 bamboo stands), and thereby inferring that 

 this rose is shy blooming; ; it is not really so, 

 it is quite as free as Irish Ekgance. 



I think our worthy President, when he 

 looked at the plants, forgot that they had 

 been cut heavily from, first of all for the 

 shows all through the month, and secondiv, 

 that over 2,000 buds had been taken from 

 those same plants for budding purposes. 



1 saw before I left Newtownards, some 

 two or three days after Mr. Pemberton's visit, 

 some plants of this rose. I think they were 

 cut-backs, probably the original plants, that 

 were literally a blaze of colour, as befits a 

 rose with such a name as Fireflame. One 

 other point. Coronation is referred to as 

 likely to prove the best rose of the vear. 

 AT highest award!" 



-P^inberton unwittingly does the jndges 

 ot the new seedling roses, and himself iu- 

 ciuded, an injustice here, as Coronation re- 

 ceived the highest award at Belfast Show. 



Herbert E. Molyneux. 



FRUIT GROWJXa- 



plantm^f, prniiini--, mul 



Full instructions as to 

 management of fniit 



trees aro Kiv(>n in Puofitable Fruit Growixo 

 a s-oUl ntedal vs^nv l.v John Wriirht. V.AF.H.. 

 ■m-K-e ls.,orbyposl Is! 3(1.. from the Publisher, 

 148 and 149, Akler^gato Street, London. 



