Rose buds splitting open... Why?

3 years ago

Chios rose was getting ready to bloom but the buds seem to be stuck and are instead splitting open vertlically. I cut off the first one that was like that then noticed two more. I am noticing that even the non-split ones aren't opening and have oddly swollen receptacles, looking like they might split too.
It's a pretty cool display of the rose's inner workings but it's ruining the spring flush.
What could be causing this?
She got a touch of mildew (Chios is unfortunately prone to it) so I sprayed her all over including the buds with a solution of 5g/liter of potassium bicarbonate with a teaspoon of neem oil last week and then again this weekend. The rest of the plant seems to be handling it fine, the foliage isn't burned at all, but could it be the spray ? Or could it be the mildew itself?
We've had some pretty strong winds and rain lately and at first I thought that the blooms were just balling from that, although they've never balled before in far more humid conditions. Does balling cause splitting?
I've also wondered if it could be a parasite of some sort? Totally stumped... Any insight would be appreciated!

Featured Answer

Diane Brakefield

3 years ago

Seaside, I think your nailed it with the balling and proliferation conclusion. Do try an autopsy if this occurs again, which I hope it doesn't. Diane

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Comments (9)

Sheila z8a Rogue Valley OR
3 years ago
Maybe botrytis seaside.
seasiderooftop thanked Sheila z8a Rogue Valley OR
seasiderooftop
Original Author
3 years ago
Thank you Sheila!

I hadn't considered botrytis, but perhaps that's it. I guess I should remove the split buds. Should I just remove the buds or is it necessary to remove the whole cane?

Should I remove the ones that haven't split too? This rose was just bouncing back from a hard prune already. Ugghh...
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librarian_gardner_8b_pnw
3 years ago
last modified: 3 years ago
I would just remove the buds as if I were dead heading. For me, botrytis tends to stick to buds and bloom. If you see fungus elsewhere, then remove those bits., too.
seasiderooftop thanked librarian_gardner_8b_pnw
Sheila z8a Rogue Valley OR
3 years ago
I agree the bud removal should do it. Weather related I bet.
seasiderooftop thanked Sheila z8a Rogue Valley OR
seasiderooftop
Original Author
3 years ago
Thank you Librariangardener and Sheila!

I have "deadheaded" the remaining split buds, as well as two that hadn't split yet but had the same wonky and swollen receptacles as the other ones did pre-splitting. I hope the remaining buds will develop normally! The foliage and stems seem healthy, so hopefully whatever it was will be going away now.

Fingers crossed, and thank you both so much!
Moses, Pitt PA, cold W & warm/humid S z6
3 years ago
last modified: 3 years ago
Could it be lots of water supplied, but dry humidity. Also consider magnesium deficiency...try application of Epsom Salts. Just thinking of other possibilitiespossibilities.

MoseMosesMoseMosMoseMosesMoseMos

(GremlinGremlin at work.)
Diane Brakefield
3 years ago
Very dry here and not humid at all, and I give my roses lots of water. I've never seen the likes of those split buds of Seaside's here. Very strange, and I hope the condition goes away permanently. Diane
seasiderooftop
Original Author
3 years ago
Thank you for your replies Moses and Diane,

Out here the humidity is around 60-80% at this time of year. I have been watering normally, which is about once a week these days, unless it rains, which still does happen occasionally in March.

I've been fertilizing regularly and the foliage is perfectly healthy now except for the usual wind damage. I'm not seeing any signs of deficiencies.

I threw out the split blooms in the pictures right after I deadheaded them, and now I wish I had examined them better before throwing them out. In the first pic, there seems to be some kind of green growth happening inside the bud.

I am wondering if perhaps a combination of balling and proliferation could be the cause: if the flower doesn't open while a vegetative growth starts inside, might the internal pressure cause the bud to burst open?

If more split I will be sure to carry out a proper "autopsy".