Help! Blackening stems??

10 years ago

So recently after a period of a month or two, my Maria Stern completely died on me! I'd deadhead as recommended and I noticed that the canes were blackening at the cut end. At first I just tried to cut below the blackened ends and see if that worked. But then I noticed that the canes were blackening from wher cane met base and going up. So the middle would stay green until completely dying off. I finally took her back to work(Lowe's b/c we have that year warranty) and at the suggestion of the garden specialist, I picked up a Gold Medal to replace. That one took less than a month, doing the same thing. I didn't check the roots of MS, but I did to GM and found they were completely dead. So I gave up on anything new for the rest of the year rosewise.

But what's worrying me now is that I recently received 3 baby roses from one of the wonderful people in the propagation forum. I planted them in a different 'pot' with new soil. When I went out today, the one little bud on Texas had fallen off and was the color of cooked petals. I didn't notice any black YET, but I'm worried it will start with these too! I haven't fertilized or used that Bayer's complete care on these little one b/c I just planted them and didn't want to shock them.

Does anyone have ANY idea what this could be?? I have a completely container 'garden' and don't have any blackspot or RRV trouble. I had an incident with aphids at the beginning of the summer and when the babies came in, but that's completely taken care of. I get the occasional powdery mildew, but nothing too bad. Is this some sort of fungus? That's what the garden specialist guessed when I told her(that or abuse from delivery drivers yanking and throwing them around).

I REALLY don't want to lose these baby roses and I'd rather not lose any of my other plants if I can help it either.

Thank you for taking the time to read this,
Sereniti

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Comments (6)

deervssteve
10 years ago
Roses die, some quicker than others. I've had my share of one caners. Of the three new bare root HT, they all lost some canes. My Double Delight is probably doing the worst. Next February, I'll prune them and see what's left. Anything not doing well will be replaced. I got a Peace at Loews in a container and it's already put out two new canes.
SoFL Rose z10
10 years ago
Drainage!
It may be root rot. Especially if you say you have them in containers. I grow almost all of my roses in containers and the only ones I have managed to kill (and there's been a few) have all rotted from the roots up because of lack of drainage.
Roses really like fast draining soil (look at the soil the roses come in at lowes, its almost like a mulch compared to potting mix).
I now plant all my roses in a special soil made for Bougainvilleas! It is very fast draining and almost identical to the soil roses usually come in when you first purchase them.

Roses don't like wet feet either so be sure there is no water tray or reservoir with your planter.

The only potting mix i have had success with is this Bugainvillia Mix (found at home depot) and Miracle Grow (because its very light and airy, even though it retains moisture because of the peat moss, it has pretty good aeration). Unfortunately the Miracle Grow organic is not as well draining so I'd skip that).
Also, be sure to make LOTS of BIG drain holes in your planters. Again, look at the containers the rose came in and how quickly water drains and try to mimic that.
Hopefully this is your problem and now you have a solution.
PS if you smell a funky smell coming from the rose after you water it (from the drained water) its DEFINITELY root rot! (The roots may also look yellow as opposed to more white which indicates root rot as well.)
Hope this helps :)
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michaelg
10 years ago
If you repotted little rooted cuttings at midsummer, the primary issues would be sun exposure and moisture as the plants readjust from greenhouse conditions and disturbance of their roots. Put them in shade for a while and gradually increase sun exposure over a month.

If you transplanted the other two roses during summer from 2 gallon or 3 gallon pots into garden soil, they also would have to adjust to disturbance of their roots while being exposed to sun and highs in the 90s.

If you have sandy soil as most do in Florida, there is no worry about drainage and root rot.

It is normal for the bark of cut cane stubs to die and turn black--depending on the length of stub that was left. As to blackening at the base, that might be a stem canker--these are common--but we would need to see a picture.
roseblush1
10 years ago
Michael.........

I agree with all that you have said above, but there are two more things I would like to add...

Almost any time you buy a plant from a big box store, the plant you are buying is probably half dead. Of course, they often don't get grade one plants, but what is worse, the people responsible for their care do not care for the roses except on the corporate schedule of watering at a specific time of day, and they don't bother to check to see if the pots have dried out. Your best chance of getting a plant that is not near death is to buy the plant the same day it is set out for sale. So, any and all TLC you can give these roses is a must.

Sometimes, I think we watch our roses far too closely. I have seen roses that really looked like they were goners, come back strong, but other times, I think they are watching us watching them and they will blacken a cane just to make sure we have something to watch. They are always surprising me.

Smiles,
Lyn
diane_nj 6b/7a
10 years ago
Florida has the issue with nematodes attacking the roots. Can anyone explain how that manifests itself? Do the canes blacken from top down?
michaelg
10 years ago
Good comments by Lyn.

Looking back, I need to say that my comment about drainage-not-a-problem was over-stated. I grew up on the Florida Ridge, and I tend to forget that so many people live in what used to be pine flat-woods, where the water table can rise to near the surface during the rainy season or after a hurricane, even when the topsoil is sandy. But the symptoms described by the OP don't sound like water-logging to me.