In hot weather, I usually assume first that HEAT is the problem--the roses are thirsty and burning up! However, I would not recommend the Bayer Rose and Flower Insect Killer (nor most of the Bayer products), They specialize in overkill--so maybe we shouldn't be surprised that the tender buds and necks are not doing well. By the way, I doubt the Bayer Insect Killer will actually do much to kill off JBs--that is mostly a marketing ploy. And as for the other insects listed, most of them can be handled in less harmful ways (midge being the exception, I believe). Just ask here when you have a problem with, say, aphids, and we can give lots of good advice without resorting to Bayer Insect Killer. There is only one Bayer product I recommend--their Bayer Advanced Disease Control for Roses, Flowers, and Shrubs--for blackspot and related leaf diseases. I'm serious --that is the only ONE I recommend. But even then, just ask here and we can suggest some ways to keep blackspot from taking over your rose garden--without using sprays. (By the way--I can only get the Disease Control at Lowe's or online.) About your immediate problem, I suggest quit using the Bayer Rose and Flower Insect Killer and give your roses more water in hot weather. Let us know how that works out. For the curious: Bayer evidently has a new name. According to their online site, the products have been renamed BIOADVANCED instead of Bayer Advanced. Kate

GrnThum, the symptom itself indicates moisture stress - not necessarily moisture shortage. I suspect that the weekly fertilization and the additional Epsom salts are contributing to Physiological Drought Look closely at the growing point(s); you will see stress symptoms there also.

It is real soil with stones at the bottom to help drainage. The container has holes at the bottom and I check every time i water to make sure excess water is draining out. I recently re-potted it so made sure that the soil was not heavy... and yes I water only when 1" of the soil is dry. I live in a flat so I can't put it on the ground... Besides, it never had issues like this before (growing it since 7 years or so) I just noticed that the long stemmed plants kinda bend when kept at this window... Could it have anything to do with the wind direction and stuff?

@aloebot I agree that some species might not do well in the peat mix once we get to a rainy season. That is completely untested at this point. I did design the peat mix to have 30% or less of the soil mix as an organic substrate (i.e., 30% peat). That effectively makes my peat mix a gritty mix, just using peat instead of bark. It is certainly more moisture retentive, but it is also fast draining. I suspect it will be a great soil for most plants and for succulents that thrive in Winter like aeoniums. For those species that go dormant in Winter, it might promote root rot. I will find out. For cactus and euphorbia, at this point, I am going to try raising them in 100% inorganic soils. The root rot problem with those has been too severe, even in the gritty mix, if I leave them outdoors. Could you update your profile to include zone information and your rough geographic coordinates? Notice how others here do that. It really helps to understand climate issues for different posters without constantly asking for that information.