I have grown roses for quite a while and have never seen this before. The first picture shows my other roses leafing out just fine. The rose in the second and third pictures shows the rose that seems to be in trouble. The new growth is yellow and the tips of the leaves are dying. Has anyone seen this before and if so, do you know what the problem is?
I live in San Diego county about 10 blocks from the ocean.
I have no idea. The rest of your plants look so healthy! I have had roses that died in a similar manner, but they were usually Hybrid teas that were past their prime and not vigorous as yours seem to be.
Most of my roses are hybrid teas and a few are floribundas. This rose is only 5 years old so I don't think the problem is old age. I fed them a few weeks ago: rose fertilizer, worm castings. sulpomag, and alfalfa meal. Do you have any other ideas?? This is a lovely pink "Bewitched."
I wish someone else would answer you; I'm not much help. I grow mainly Old Garden Roses because I don't do well with Hybrid teas and their relatives. It sounds as if you are doing a good job with yours. I can't imagine why that one is so ungrateful!
Rose Fertilizer: ??? Is it synthetic? I presume it's organic since you're using organic amendments and I presume it contains N-P-K, K - being POTASSIUM. My guesstimate - either synthetic or organic it already contains Magnesium Sulfate being a rose fertilizer. - Check!
Worm Castings: Check! Wonderful stuff! Also a source of Magnesium. Trace amount of NPK as well.
Alfalfa Meal: Check! Great stuff too. May also contain NPK especially K as in Potassium. and some Sulfur.
The above 3 would be sufficient enough to get your roses going. But why oh why,
Did you had a soil test done and the result suggested you need to add excessive amount of potash and magnesium? Seriously, this might be the problem.
Of course, there can be other reasons too. Pathogenic fungus among others. With limited info and just one rose bush, I'm not really sure what the problem is.
But when you mentioned Sul-Po-Mag, it triggered an alarm on my head. Either you have an over load of Magnesium or Potassium toxicity. The symptoms for both - exactly what you're showing on photo 2 and 3.
A breakdown of Sul-Po-Mag (sulfate of potash-magnesia) is: N-0, P-0, K-22 (soluble). Also contains 11% Magnesium and 22% Sulfur. I don't know how much you're putting per rose bush, but combined with your fertilizer, that's way, way too much Potassium. A well balanced rose fertilizer is all you need. If you look at the numbers on either synthetic or organic rose fertilizers, the K value is usually the lowest and not even reaching the 22 mark at it's highest or at least equal to the N value with P (Phosphorous) as a little higher. Too much potash is not literally toxic to roses, but the imbalance will lock up the soil and will prevent delivery of other nutrients - especially nitrogen!
Too much Magnesium on the other hand will prevent delivery of Potassium. Magnesium plays a vital role if used in minute amount, but like everything else in excess is toxic. A rose specific fertilizer already contains Magnesium Sulfate and should be enough until the next application. A better alternative if you feel the need for extra magnesium is use one teaspoon of Epsom Salt per gallon of water.
I hope I explained or helped you a bit. Again, the problem could be something else, but I think it's too much potassium. I was just wondering how you got hold of solpomag since those kind of products are usually used on agricultural lands were crops are harvested constantly with the aid of proper soil testing and is usually counter acted with appropriate amount of nitrogen and phosphorous. I do commend you however for using organic products. Greensand would be a better alternative if you need an extra kick of potassium. Though for now, until you identify the problem, I recommend you stay away from more potassium. LOL!
I have showcased my rose garden in one of the threads here and not once have I used extra potassium or even extra phosphorous (bone meal users anyone?) in my garden and everything grows just great.
Spraying is probably a good idea but I would be surprised if it was rose midges - they are supposed to be rare in southern California.
Have you ruled out stress related to gophers or ground squirrels? I have had many roses that were hollow underneath with no overt signs above ground. You can test by useing a shovel handle to tamp around the crown.
It was rose midges. Tiny white 'threads' 1/25 in. long. I sprayed yesterday morning and by afternoon there were all the little dead white threads as well as a lot of dead aphids. I'm going to spray again in a week as the midges fall to ground, mate and hatch little midges. It's a 10 day cycle so spraying every 7 days should outfox them. I spray not only the roses, but the ground around them.
I have issues with midges here as well. They seem to blow in and out with the wind. Yes, the white threads are the telling sign. What are you using to spray? Spinosad seems to be working for me. I have a huge area to contend with and that doesn't seem to blow away.