November 1, 1888. ] 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
407 
land and amongst manure, also young gardeners in houses whose boots 
are half their time wet, as well as all persons who have to pass through 
the slush of winter, may be reminded of the comfort and advantage they 
may derive by the systematic use of this cold-preventer and boot-pre¬ 
server they have often seen advertised, and those of them who have not 
tried it are advised to do so, for it is good. 
CONFERENCE PAPERS. 
CANKER: ITS CAUSE AND CURE. 
By Mb. James Douglas, Ilfobd, Essex. 
This troublesome disease in fruit trees has very frequently been the 
■subject of discussion in the gardening periodicals and elsewhere. 
Nearly every gardener has had to deal with it in his experience of the 
details of fruit culture, and as I had considerable experience of it some 
twenty-five years ago, in an old Essex garden, I may at least claim to 
bring it forward as a subject for discussion. 
At the outset it may be taken for granted that it is absolutely 
necessary to ascertain the cause of a disease before any attempt can be 
made to find a remedy. The late Mr. Robert Thompson, author of the 
■**' Gardener’s Assistant,” and Superintendent of the Royal Horticultural 
Society’s Garden at Chiswick, writes on canker with considerable 
diffidence. In the work above cited, page 381, he says : “ The cause 
of canker is imperfectly understood, and so consequently is an effectual 
remedy.” 
His idea of the causes of canker, as summarised in his admirable 
work, are:— 
I.—Sudden checks to the vegetation of the tree, especially in spring 
and the early part of summer. 
U. —Derangements of the flow of sap from vicissitudes of heat and 
cold, as well as of moisture and dryness. 
III.—Unskilful and severe pruning. 
IT.—Vitiation of the sap by deleterious substances in the soil or 
■subsoil. 
V. —Dryness at the root doubtless gives rise to a species of canker, 
which manifests itself on the younger branches and on the shoots. 
Referring also to Lindley’s “Theory of Horticulture,” page 110, it is 
stated that a Mr. Reid of Balcarras had shown “ that one of the causes 
of canker and immature fruit, even in orchards, is the coldness of the 
soil. He found that in a cankered orchard the roots of the trees had 
entered the earth to the depth of 3 feet; and he also ascertained that 
during the summer months the average heat of the soil at 6 inches below 
the surface was 61° ; at 9 inches, 57° ; at 18 inches, 50° ; and at 3 feet> 
41°. He took measures to confine the roots to the soil near the surface, 
and the consequence was the disappearance of canker and perfect 
ripening of the fruit.” 
Another cause has been suggested—viz., insect agency. But this 
view of the matter will probably not be sustained by practical gardeners 
generally. That insects of various kinds, including that troublesome 
pest American blight (Aphis lanigera), will penetrate into the cankered 
part for shelter is likely enough. Indeed I can assert they do ; but they 
are not there as the cause of canker, but because the cankered part 
affords a secure resting-place, which the smoother, healthier portion of 
the bark does not. Indeed I can also assert that cankered trees may be 
found in the garden with insects upon the affected part, and others near 
them also cankered with no insects upon them. 
My contention is that canker is caused in two ways, and affects two 
different parts of the trees. Perhaps the most serious disease is that 
which affects the trunk or larger branches of the trees. This I hold is 
caused by the roots pushing downwards into cold, undrained, or 
unsuitable soil. The other aspect of the disease is that which lays hold 
of the twiggy portion of the trees, for even the one-year-old shoots do 
not escape. The immediate cause of this is probably owing to the 
rupture of the sap vessels by frosts, when the sap is in an active state. 
But I have a firm belief that the primary cause is also to be found in 
the state of the roots, which being in an inactive state owing to unsuit¬ 
able soil, or their penetration to a great depth, prevents the perfect 
ripening of the wood, or maturation of the blossom buds in the autumn. 
I come now to my own experience in our old garden twenty-five 
years ago. There were upwards of 100 trees of various sizes, some only 
a few years old, others 100 years planted at least. Most of them were 
cankered, and in places where the old trees had been removed and young 
ones planted canker showed itself in a few years. 
The soil was light, over a gravel subsoil, and was naturally drained ; 
the water did not stand on the surface for any length of time, even in 
very wet weather. I was confident that want of drainage had nothing 
to do with it, and that the fault was in the cultivation. Young trees 
seldom do any good planted amongst old ones, even if the soil has been 
well dug up and enriched with manure where the roots are to be placed. 
They require a wider and better field for their ramifications. I found I 
had to make gravel paths as well as fruit borders, and as most of the 
old trees were on the wane, and the young ones of but little value owing 
to their cankered state, it was thought best to remove them. But they 
were not all removed at once, as it was necessary to keep up a supply of 
fruit for household use. A space about 30 feet wide was lined off 
through the whole length of the garden, and was cleared of all trees 
and bushes. In the middle was a space G feet wide for a gravel path. 
The borders on each side, about 12 feet wide, were trenched where 
possible 2 feet deep, and we found the gravel cropped up in places within 
a foot of the surface. Where this was the case the gravel was taken 
out and used to make the path, the soil from the path being used to fill 
up the space from whence the gravel was removed. A good dressing of 
decayed farmyard manure was worked in with the operation of trenching, 
and as we could obtain good clayey loam a barrowload of it was spread 
out over 2 square yards, and 6 inches below the surface ; a thin layer of 
decayed manure was placed on the ground before the loam. This was 
easily done as the work proceeded ; one man could wheel in the loam 
and manure to two at work trenching. 
When the work was finished we had a good gravel path with Box 
edging on each side, and the borders, through the trenching and 
manuring, were about 8 inches higher than the surrounding ground 
level. I had to plant the trees soon after the trenching was finished ; 
they were Apples, Pears, and Plums on various stocks and in consider¬ 
able variety. We planted them but 6 feet apart at first, and when they 
were planted a portion of good decayed turfy loam was placed round 
the roots. With this treatment, as might be expected, the trees made 
good clean growth even the first year. 
As we manured rather too heavily by placing in two layers of fat 
stuff I thought it best to retrench the ground the next year, lifting the 
trees as the work proceeded. I found they had made a mass of fibrous 
roots into the loam, and when the trees were replanted again quite 
another barrowload of loam was placed round the roots, but no manure 
this time. However, round the roots of each tree some decayed frame 
manure was placed to keep the frost from them. 
The trees made good clean growth again, and formed plenty of 
blossom buds. But I found G feet was too close even for Apple trees on 
the Paradise stock, and they had ultimately to be removed from 9 to 
12 feet apart. In the course of the next ten years other borders were 
made, and in some cases the trees which were too close to each other 
were thinned out to furnish them. Many of the old cankered trees re¬ 
mained in proximity to the young ones for quite ten years, and with some 
two or three unimportant exceptions none of the young trees cankered. 
This shows, I think, if the disease had been caused by insects they 
might have travelled from the old diseased trees to the young ones. It 
was some seven or eight years before any canker appeared, and then 
only on the Dumelow’s Seedling or Wellington. These trees were lifted, 
the canker cut out, and they were replanted again with fresh loam 
under and over the roots. The cut out portions soon healed over, and I 
saw no more of the disease. 
The object I had in view was to encourage the roots up to the sur¬ 
face, and to keep and feed them there. The entire border quite close 
to the surface was full of roots, because it was not dug over, but merely 
scratched with a fork or hoe ; and during winter and summer there 
was a thin layer of manure over it. Within the borders was the kitchen 
garden squares, well manured, to be cropped with vegetables, and the 
roots ran into this freely. We were well within the London fogs 
being less than seven miles of the Bank of England. In our new garden 
not much further out we had to do the same sort of work, but the soil 
was much better, being a medium clay of considerable depth, and 
nothing more was necessary than to trench the ground twice over in 
order to incorporate the top and bottom soil well together. We had to 
drain it, and find a good outfall for the water. In such a case the drains 
should be about 6 yards apart. 
I have brought this subject forward as much in the interest of 
amateurs who own small gardens, and who do most of the work them¬ 
selves as a relaxation from sedentary occupations, as in that of 
gardeners. It is quite true that some classes of soils are more suitable 
to fruit culture than others, but my experience is that some soils are 
condemned when neither the soil nor the climate, but the culture alone 
is to blame. Only the other day I met a person who has several 
hundreds of fruit trees in his garden, most of them young ones, and, a 
considerable proportion are showing canker on the larger branches. I 
examined the soil, and found that it had not been broken up more than 
10 inches deep ; and, further, all sorts of vegetable crops were planted 
