What's wrong with these rose bushes please?
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reddit.comPosted Aug 7, 2023, 8:36 AM UTC
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reddit.comI would start by repotting them! Roses love lots of room to grow. Depth is especially important and the extra space also helps retain soil moisture for longer. It also keeps them cooler in hot weather and insulated in the winter.
I've got my full-sized roses in 20"x20" pots (or 50cm a side), but I know some Rose growers suggest 2'x2' (60cm a side)
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I have just transplanted them, with new organic soil.
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prune all the infected leaves, a good spray of some neem oil spray could benefit and add some charcoal to the soil as well
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Yes, definitely remove any brown or diseased leaves! The yellowing leaves towards the bottom look like spider mite damage to me. You can check the underside of the leaves to make sure. If there are spider mites, the underside of the leaves will have a whitish powdery look to them with some black dots.
They are the bane of my existence right now. I used rubbing alcohol on a q-rip to painstakingly make sure I got them all off the leaves (especially the underside) after removing the ones with the most infestation. Others say you can get them off with a spray of water, but I don't have a hose on my back deck. Then I sprayed with "Bonide MiteX" every three days (egg laying cycle) making sure to soak the underside of the leaves. The MiteX doesn't have any crazy pesticides in it, it's just a bunch of essential oil concentrates that smother mites. Spider mites can actually grow resistant to insecticides pretty quickly.
@nyc_dee26, I've never heard of mixing in charcoal before! What does that do?
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it kills any fungal root issues and helps drainage and over moisture from watering !
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Yea. Transplant shock then susceptible to fungus and insects. Don’t transplant when actively growing. Roses why sturdy, don’t like to have their roots disturbed.
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Put it I. A larger pot and mix your soil with 1/4 tsp of epsom salt and a little bone meal.
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Probably no pesticides use. You have multiple bugs on there unfortunately, with spidermites being the most devastating. There’s something about roses that just makes them attractive to mites when they the plant becomes water stresses. Use Bayers two in one with acephate for mites control.
is the problem just mites? Do you know any "natural" remedy without chemicals? Or do I go straight with chemicals? I have only given him a nettle-based 3in1 compound every 15 days.
Water hose in “shower” mode to rinse off all mites. Then either dip in soap water or spray neem oil. To me, dip the whole plant upside down into a bucket of soap water works better. You need to water down the leaves daily to rinse off the mites for a couple of weeks. I recommend in the morning or when the sun is still out to prevent from the black spot.
Look into companion plants to attract the right bugs to manage pests. I use zero chemicals on mine as I intend to use the flowers for edible applications.
You really don't need to always use chemicals. It damages the ecosystem and beneficial organisms.
Will your plants always look picture perfect, no. But, will all the pollinators and wildlife be better off? Absolutely. My small garden is filled with happy wildlife. I've seen bugs I haven't seen in years. Colorful dragonflies, an assortment of butterflies, native (not store bought/poached) ladybugs, different types of bees, happy birds that don't die from eating poisoned bugs.
I love the ecosystem created with your appeoach.
What kind of plants do you suggest having?
Depends on where you live. Are you in the US or somewhere else? If I. The US, what state? The goal is to attract native species to deal with pests while improving ecology. . Why do I do this? Because I am infinitely lazy. If I can get nature to do what it does best, then I don't need to worry much about pesticides, herbicides, fungicides, and constant application. It should all balance out. Aphids are eaten by ladybugs, hoverflies, etc. Those bugs are eaten by birds, which eat more bugs. Birds are prey and pollinators and seed spreaders. If done right, you can have crows watch over your garden to manage various small animals. Etc etc etc. . Also, it's pretty and more interesting to see what cool looking bugs and birds and animals are around.
The best natural metod that works like a charm for me is buying a few bags of thripex, they eat spider mites and other nasty bugs!!! You just hang few on the bush and that’s it.
thanks for the suggestion.
Nearly everything you use are pretty much chemicals but a safer chemical that I have found success is polymer based. The high end polymers are used in agriculture to reduce freezing and drought. My cheap method since I am a chemist, is to use Elmer’s glue which is nontoxic. Take 5 ml of Elmer’s glue, add 0.5 mL of pure Castile soap or coco glycoside surfactant and mix the two together until it forms a paste. Slowly dissolve into 1 liter VF and bring up to mark. Shake to dissolve. After moving the rose to a shaded area, gently spray solution covering all parts of the plant including the underside of the leaves. Shake off excess and let air dry. The film will inactivate any spores on the top side of the leaves, and kill instantly all mites under. The film will also kill all eggs left behind by the mites. All open wounds in the plant will be sealed under the film. You may bring the plant back under the sun after one day in shade. Treat again after one week using the same procedure as described above. It is imperative that no excess solution pools on the leaf. You just want a thin layer. The polymer will dry semi gloss, and will remain effective for about a month after application.
Thanks, I'm going to try a more natural solution first, to see if that works better. Potassium soap and Neem oil seems to be the combination.
This is pretty good. Thank you for sharing. I have the same problem as OP except that it's about 24 Rose bushes, 7 magnolia genies, plus various fruit trees. Are you using water as a solvent? I've been using 2 Oz neem oil, 2 teaspoons kirkland dish soap, 1 quart 70% isopropyl alcohol, diluted to 1 gallon with water. I've managed to control it, but I have to repeat every couple of days. I see the mites under the microscope. Most mites appear dead and most eggs seem pretty dry. However, after only a couple of days, they're back with fresh eggs and all. Trying this and various other combinations, it's turning quite expensive. I live in SoCal. Again, thanks for the tip.
You’re welcome! One of the reasons why I don’t like to use oil based products is that at higher quantities through cumulative applications, it can damage leaves by breaking down the leaves waxy cuticles. After several applications, the rose leaves start to turn yellow and sickly which some people mistaken for black spot, but it is different as the entire leaf will yellow with light brown dots instead of the large fuzzy brown spot. Neem is also a bit more toxic to bees. The solvent that I use is just plain water to dilute down the polymer. Since you are in California, plant sunburn is something else you might have to deal with. For some reason, when roses become heat stressed, they attract more spider mites. One theory is that the rose release some kind of aromatics as a result of reducing water loss, which can signal spidermites. The cheap polyvinyl acetate forms a barrier over the stomata to reduce water loss of the leaf but still allow the passage of air. This barrier camouflages the leaf from mites and even fungus spores which can recognize rose leaf cuticle at the microscopic level. As for the sunburn, to the one liter solution, you can add 1 teaspoon of titanium dioxide and 1/2 teaspoon of zinc oxide powder and mix before spraying. Both powders are used in mineral based sunscreen and are extensively used in turf management on golf courses. The added benefit of TiO2 is its ability to react with UV and sensitize and kill spores and even interfere with mites reproduction. The more expensive option of polymer would be Antistress 2000, or Crowning Glory from FloraLife. The Weed growers community has a lot of success with using Antistress for mites prevention. Good luck!
And cut infected leaves and parts of the rose as well! Throw them right away without letting them touch other plants or roses that you might have.
practically all... would it be too much to do a winter pruning at this time?