August 8, 1866. ] 



JOURNAL OF HOETICULTURE AND COTTAGR GARDEXER. 



105 



all went wrong in about a mouth, while a common ono of 

 simpler construction has been in uso for some years. In fact I 

 hope to see a preat imiirovement in thorniomelors and other 

 meteorological instruments, and until s\Kh is really the case, 

 the public can hardly bo expected to buy the expensive article 

 when its merits are only in its outward adornment. 



Notwithstanding the heat of the present season, the ther- 

 mometer has not yet reached the maximum of IH.'id, 1H57, and 

 18.'J8, as will be seen by the figures below, which iuilieato_ the 

 hottest days in each year, ns taken in the manner described 

 above : — 



1854. July 2.'>th thermometer S7° 



1855. .Tune29th „ 9:i 



IB.W. July :ilst and Ani^st 1st „ 95 



1857. Jnuo '2(ith and 2Sth, aud Aug. 23rd „ 95 



185H. Junu 15tli aud llith „ 97 



1S59. July 12th „ 92 



1860. July 2nd „ 78 



1861. August 12tli „ 88 



1862. Mav 6th „ 86 



1863. August 9th „ 87 



1864. Jidy 20th 87 



1865. Juue 2l8t and 23rd „ 92 



It is somewhat remarkable, that the heat attained on the 

 21st and 2;ird of Jvme in the present year was not approached 

 by 8° in any of the days before or after these dates, and up to the 

 time I write, July 28th, the thermometer has only once reached 

 86°, aud that was on the 15th of JiJy ; but a long period of 

 dry hot weather may occur without any extreme being ap- 

 proached, and it is questionable whether an unusually hot day 

 amongst others of medium character is beneficial. One of the 

 most remarkable instances of this kind occurred on May 6th, 

 1862, which, as shown above, was the hottest that season. I 

 may, however, remark, that the present season has presented 

 a longer period without rain than any previous one, for none 

 fell here (Staplehm-st), for twenty-six consecutive days in June. 

 The rainfall, however, of the six months ending the 30th of 

 that month is a full average. The early months were wet, and 

 during July nearly 3{ inches of rain have fallen. — J. Robson. 



MILDEW ON ROSES. 



Judging from what I have seen, as well as from complaints 

 I have heard from others, this pest to Rose-gi'owers seems to 

 be unusually prevalent this season ; and from recent inquiries 

 in The Jodrnaij of Hoiiticulture I conclude that some in- 

 formation on the subject will be acceptable to many of your 

 readers. Though I may not be able to advance anything in 

 my present communication that is not known to most Rose- 

 growers of experience, I may be able to convey some useful 

 information to such of your readers as are, like myself, begin- 

 ners in this most pleasurable branch of floriculture, by select- 

 ing aud condensing what has been advanced by some of our 

 best writers and most experienced Rose-growers. 



With regard to the cause of this disease, we find that, as 

 with diseases affecting the human frame, " doctors sometimes 

 disagree ;" and the fact seems to be that, as to this part of 

 the subject, we are very much in want of certain and reliable 

 information. Mr. William Paul, in his " Rose Garden," does 

 not venture to allude to any positive cause of the disease, but 

 Kays negatively, page 118, " If the situation (of the roseiy) bo 

 airy and suimy, there is little to fear on account of this dis- 

 ease." Mr. Cranston, in his " Cultm'al Directions for the 

 Rose," quotes the late Mr. Knight as saying, " The secondary 

 and immethate cause of this disease has long appeai'ed to me 

 to be the want of sufiieient moisture from the soil, and excess 

 of humidity in the air, particularly if the plants be exposed to 

 a temperature below that to which they have been accustomed." 

 This, I conclude, refers to Roses in pots, or newly planted out 

 from a frame or some such sheltered situation. An anonymous 

 writer in your Journal of March 28th, page 243, says, " Mildew 

 is seen under extremely diiJereut cireumst.ances, but 1 think is 

 generally caused by defective root-action, the roots not being 

 able to supply the sap fast enough to the leaves, or sometimes 

 from the leaves being in a higher temperature than the roots ; 



and it would seem as though mildew, attacking 



healthy young Rose shoots exjjosed to sun and air in the open 

 ground, must differ vei-y much from the mildew which attacks 

 plants in cold damp houses in the winter, aud yet I am still 

 inchued to think the cause is much the same." The Rev. Mr. 

 Eadclyfle, perhaps our highest authority on Rose-culture, 

 seems, indirectly at least, to ascribe its prevalence to extremely 



high culture, or, in other words, to gross feeding ; for in an article 

 on the Manetti stock ho says (see Joubnal op Hohticultuee 

 for April 22ud, 1862, page 03), " It carmot be denied that 

 Manetti Roses, as a class, are more subject to white mUdew 

 than Briar Roses, and that the higher you cultivate the more 

 you will be subject to it." To this latter remark I can fuUy 

 subscribe ; for while I confess myself unable to assign any 

 certain cause of the existence of the disease, I believe it may 

 always he developed by high or gross feeding. The soil iu 

 which I cultivate my Roses consists to a great extent of de- 

 cayed turf from an old pasture mixed with the soil on the spot, 

 which is moderately heavy and well drained ; it is also well 

 maum-ed with decayed stable dung, and 1 find that the appear- 

 ance of mildew always follows a liberal api)lication of strong 

 liquid manure. This consists of house-sewage, by which I 

 mean the whole liquid refuse from the house, consisting o£ 

 kitchen and chamber washings, soapsuds, &c. This, in wet 

 weather, is diluted with an eipial ([uantity of pure water, and 

 in continued dry weather with dcuihle that quantity, and is 

 applied iu the proportion of a gallon to each tree on an average 

 of once a-fortnight from May to September. 



Wliatever may be the cause of mildew, as regards its existence 

 in the rosery it is, I believe, developed or increased very much 

 by circumstances over which we have no control — I mean, by 

 atmospheric causes, as the existence of long-continued seasonB 

 of drought, or of dull, cloudy, wet weather. But while we can, 

 perhaps, do little to prevent the existence of the evU altogether, 

 we may do much to remedy it where it does exist. The reme- 

 dies recommended for this disease are indeed ma)iifold, and 

 one or other within the reach of every Rose-grower. Mr. W. 

 Paul, in the " Rose Garden," page 118, says, " Dusting the 

 leaves with sulphur is the best remedy. Watering with a solu- 

 tion of nitre is also said to destroy it." Mr. Rivers, in the 

 " Rose Amateur's Guide," recommends the same remedy — 

 " sprinldiug with sulphur." Both these instances, however, 

 refer to Roses in pots. Mr. 'Cranston, iu his "Cultural Di- 

 rections for the Rose," recommends the same remedy, giving 

 the preference to black sulphur over yellow ; but adds, "AVhere 

 sulphur has failed to arrest its progress, Gishurst compoimd 

 has been applied, and with wonderfully good effect. The quan- 

 tity used has been from 24 to 3 ozs. to the gallon of water. 

 The plants affected are syringed or well wetted with the mix- 

 ture, and if the shoots are at all tender they must be syringed 

 over with clear water in a few hours afterwards, otherwise the 

 young buds which are formed at the cuds of the shoots may 

 be destroyed ; also, when allowed to dry upon the foUage it 

 has a disagreeable appearance. One or two applications ia 

 most instances will be sufficient ; but when the disease hag 

 been allowed to establish itself it must he applied weekly until 

 it is cured." The Bev. W. F. Radclyffe, in his lecture on, 

 Roses, delivered before the Royal Horticultural Society (see 

 Journal of HoETicoLinnE of July 2Gth, 1804, page 07), gives, 

 as the most effectual remedy Iluowu to him, " 2 ozs. of blue 

 vitriol, dissolved in a little hot water, and then mixed with 

 a stable-bucket of cold water, aud poured from a watering-pot 

 with the top (rose ?) on over the leaves." Your correspondent 

 •' X. Y. Z.," before referred to, writing in the Journal of March 

 28th, says, " There is no more certain cure for mildew on Roses 

 in summer than a thorough soaking of water at a temperature 

 of 80° or 90°." " Upw'ards and Onwards," I think, speaks of 

 liquid manure heated to 140° ; and iu your answers to corre- 

 spondents in the Jom-nal of July 18th, you recommend syring- 

 ing the plants with lime water to destroy the fungus, and then 

 to water the roots copiously, mulching the surface, and to 

 continue watering abundantly during dry weather ; and you 

 add that " weak liquid mauiu'e once a-week will benefit the 

 Ir.'ss." 



Here, then, we have plenty of remedies to choose from. The 

 two which I have tried myself are the Gishurst compound and 

 the solution of blue vitriol, and I can answer for timt efficacy of 

 both. Of the two I give the preference to the Gishurst com- 

 jround, and this I never tise stronger than 2 ozs. to the gallon. 

 My reason for the preference is, that while it is as efBcacions 

 as the blue vitriol, I find it does not mark the foliage so much. 

 Indeed I find iu applying the latter that any Roses wholly or 

 partly expanded, but especially those which are white or light- 

 coloured, become so covered with black spots that they have 

 to be destroyed. The foliage also becomes spotted, thotigh not 

 to such an extent. In applying the Gishurst compound I mis 

 it, if possible, two days or more before using it, and. choosing 

 a didl day, syringe the plants about the middle of the day. I 

 then syringe them over, about six or seven o'clock the some 



