October 16, 1915 



HOETICULTURE 



ROSE GROWING UNDER GLASS 



( ONUl CTED BV 



■C^i^^yZA^^ 



Questions by our readers in line with any of the topics presented on this page will be cordially received and promptly answered 

 by Mr. Ruzicka. Such communications should Invariably be addressed to the office of HORTICLLlUKl,. 



Treatment for Blackspot 



ilr. Arthur Ruzicka. 



Dear Sir — We have read your report on rose-growing as 

 was published in the Horticultike under date of .\ugust 

 28th. 



We are at present troubled with black-spot and some 

 of our benches of Ophelia roses are affected. We would 

 appreciate very much to receive from you full information 

 regarding the mixture Amnionical Copper Carbonate. We 

 would also like to know how this drug is to be applied, as 

 we have never before used this. Any other information re- 

 garding the treatment of black-spot will be greatly appre- 

 ciated. 



Trusting you will favor us with an early reply, we re- 

 main. Yours verv truly, 



T. A. I. & SO.NS. 



Eegarding the use of copper carbonate as preventive 

 for blackspot, to two ounces of pure copper carbonate 

 add enough ammonia to thoroughly dissolve it. The 

 nii.xture is then added to two gallons of water, well 

 stirred, and applied at once. Glass jars should be used 

 for dissolving the copper with the ammonia. Where 

 a larger amount is necessary it can be mixed in a 

 l)arrel, but we always mixed it in small quantities only, 

 as it loses strength quite rapidly after mixing. 



Further treatment for blackspot on Ophelia may be 

 as follows: Keep the plants on the dry side for a while. 

 This does not mean drying them out until they shrivel 

 but let them get fairly dry before they are watered. 

 Avoid syringing for a while as this will spread black- 

 spot quicker than anything. Go over the plants care- 

 fully and pick off all leaves that are affected. This 

 cannot be done if the plants are badly attacked but if 

 the disease is titken in time it will be checked this way 

 a great deal. After picking as many of the diseased 

 leaves as can be safely taken apply the ammoniacal 

 copper carbonate and keep the plants on the dry side. 

 Give plenty of air, both night and day, and try to in- 

 duce the plants to grow as much as possible. Never 

 neglect to blow lime under them at night after water- 

 ing, and if the weather is dark and rainy do this 

 whether the plants are watered or not. If the benches 

 do not dry out readily it may be that the soil is some- 

 what sour, and a top dressing of lime will be a great 

 help towards drying the benches out. Use air-slacked 

 lime, freshly slacked, and apply enough to nicely whiten 

 the surface of the soil. This can be applied one day 

 and the benches watered the next, or it can be allowed 

 to lie for several days, after which it will have to be 

 rubbed over to break up any caking that may have 

 taken place. The copper carbonate can be applied two 

 or three times a week if necessary. It will not cure 

 the spot but will keep it from spreading by killing the 

 spores that the mixture touches. When it will be safe 

 to resume syringing, see that it is done quite early in 

 the day so that all the plants will be dry before night 



comes. Also see that it is done quick and well, with 

 good pressure, so that the whole house is not drenched 

 from top to bottom, taking a long time to dry out. It 

 will be well to blow a little lime around the house dur- 

 ing the morning and afternoon of rainy or wet warm 

 foggy days. This is done by walking backwards in the 

 walks with the bellows, holding them up level with the 

 shoulders and working them so that the dust will cir- 

 culate freely through the house, at the same time not 

 proving so irritating to the one who has to do the work. 

 Through constant use of lime, and care in watering, 

 we have never had a serious case of spot. 



Watering 



Be careful to see that the plants are not overwatered, 

 more so the plants that have just finished a crop. These . 

 will be proity well cut off and if they are kept too wet 

 they will not break as strongly as they should. Keep 

 l)hnits like these on the dry side. Then again, plants 

 that are covered with buds about ready to show color 

 should never be allowed to become too dry as this would 

 hurt the buds and they would likely be small and not 

 well developed. If there are any poor plants among 

 tile others they will not take very much water, and 

 therefore should be skipped when watering. To make 

 sure this is done it is best to go around some time with 

 a box of lime and scatter a little around each plant. 

 Thus marked, they will be easier to avoid when apply- 

 ing water. Late planted roses should be kept on the dry 

 side, so that they will make as much root as possible^ 

 l)ut this docs not mean that they should be dried out 

 vintil the soil cracks. This would damage the present 

 roots a good deal, not only tearing them where the soil 

 cracks, but also killing a good many by the too dry a 

 state of the soil. With cold frosty nights it will be 

 necessary to use the fires more and the plants will dry 

 out quicker, so they will take more watching. The soil 

 often dries out in the bottom of the benches first, so 

 when examining benches for watering it is best to reach 

 down to the bottom. Be especially careful not to let 

 a rapidly growing bench ot Beauties get too dry as this 

 would be apt to cheek their gro\vth, and once they stop 

 they will be hard to get going again. In using liquid 

 manure make sure that the jilants are wet enough he- 

 fore the liquid is apijlied. We generally water with 

 clear water first and then apply enough liquid to go 

 through the soil nicely, without I'linning through too 

 iiiucli. This takes a little longer but the work is well 

 done and a good deal of manure is thus saved. Wc 

 can water two houses with the liquid that would be 

 needed to do one were it not for the clear water used 

 before using the li<iuid manure. 



