It just looks like a spent bloom to me. I'm new to knockout roses so I'm really no help. I just purchased some a few days ago, and I have blooms on mine like that. I assumed it was where walmart was watering them overhead, but I don't know for sure.

It just looks like a spent bloom to me. I'm new to knockout roses so I'm really no help. I just purchased some a few days ago, and I have blooms on mine like that. I assumed it was where walmart was watering them overhead, but I don't know for sure.

Hmm. it's just mighty ugly. I don't recall them looking like that last year. but you could be right

Could some kind of insect attacked that specific set of flower buds? It looks similar to mine when something attacks a buds. Wait and see how the rest open, and look close for insects.

Botrytis fungal disease attacks rose petals during cool, wet weather. It causes soggy brown spots that later become crispy. It can also cause pink spots on pale roses. Often the symptoms are worst on the outermost petals because they are exposed longer. There is little you can do about it, but it spreads only under certain weather conditions.

Not scientific by any means but that reminds me of when rain kind of rots the buds on the plant, and then they open up with rotted looking petals on the inside.

What MichaelG said

If you don't like how they look, snip off the bloom directly under the bloom--then you won't have to look at them. By the time the plant produces more blooms, the weather will have probably changed and therefore the rose blooms won't be suffering anymore from Botrytis fungal disease (see Michael's post on that).

Kate

I see... but my rose bush isn't going to die, right?

From what I can see of the leaves in the background the plant looks healthy. I think your plant will be fine.

No, botrytis will not kill the plant. It happens more some years than others, you'll get used to it over time.

I have bad news for anyone with Knockout roses....myself included. They are quickly being wiped out by rose rosette disease. Mites blow in on the wind and transmit a virus which kills the plant. If you catch it quickly and cut out infected stems it will help for a while. I had to dig out all of my roses and burn them.

Just a note to Marty's caution: It is not just Knockout roses that can get Rose Rosette Disease (RRD). Just about any rose can get it (in fact, I'd guess ALL roses can get it).

Knock Out Roses are NOT more susceptible to RRD than any other rose.

Keep an eye out and if your rose starts growing really ugly witch's broom type growth or something like that, take a pic and show it here. We can probably help you identify whether or not it is likely to be RRD. No point going into a panic over everything that can happen to a rose and assuming it is RRD. Make sure it is diagnosed correctly first. If it is RRD, then, yes--you will probably have to destroy the plant as Marty says.

I have lost about 1 rose per year to RRD for the past several years. None of the lost roses was a Knock Out.

Kate

The following was stated: "Just a note to Marty's caution: It is not just Knockout roses that can get Rose Rosette Disease (RRD). Just about any rose can get it (in fact, I'd guess ALL roses can get it).
Knock Out Roses are NOT more susceptible to RRD than any other rose. "

H.Kuska comment: The above may be correct, but it also may not be correct. Controlled research is needed. One way that it may not be correct is if a certain type of rose all have another virus. The first virus may make it easier for the rose rosette virus to overcome the immune system. This is a quote from research titled:
"Fate of artificial microRNA-mediated resistance to plant 1 viruses in mixed infections"

"However, when the plants were pre-infected with these viruses, TuMV was able to co31 infect 12-4 plants pre-infected with TRV, CaMV, and, particularly, with CMV. So, pre32 infection by another virus jeopardizes the amiRNA-mediated resistance to TuMV."
http://digital.csic.es/bitstream/10261/93508/1/Martinezetal%20Phytopathology.pdf
-------------------------------------------------
Is there any evidence to suggest that this occurs with successful rose rosette infections?
Yes, there is: 1) Early on infected multiflora rose was found to also be infected by a cryptic virus (H.Kuska comment: which is transferred through the seeds).
http://www.sipav.org/main/jpp/index.php/jpp/article/view/664/451
AND
2) Recently rose rosette infected roses were reported to also be infected by Blackberry chlorotic ringspot virus (BCRV). See the following quote: "The case of Blackberry chlorotic ringspot virus (BCRV) is of particular interest because the virus has been found to be an integral part of blackberry yellow vein disease and is widespread in rose plants affected by rose rosette disease." (H.Kuska comment: BCRV is also transferred through seeds.)
http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-08-13-0866-RE