22,152 Garden Web Discussions | Roses

What is wrong with my knockout roses?
Posted by dandelionwishes June 15, 2015
11 Comments
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dandelionwishes

So these red bugs look like box elder bugs - the immature ones that are all red. They were lined up like armies in symmetrical rows on the evergreen shrub next to the roses. (I hate evergreen shrubs, I have pulled out just about every evergreen shrub except these). The weird thing is, there were no holes in the rose leaves before, they were just pale pale yellow. Now, there are these bugs, and some of the leaves have holes in them. These bugs are about the size of my pinky fingernail. I am fairly sure they are box elder bugs. I have cut back the roses as far as I could. I didn't put much potting soil on them, just a little bit around the base because the potting soil was dry and I thought maybe the nutrients in it would be helpful. I will put some mulch lightly over the top. I am just glad it doesn't appear to be the dreaded red rosette virus thing. I might have to plant something else in this spot though if these guys don't pull through.

    Bookmark     June 16, 2015 at 8:31AM
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Patty W. zone 5a Illinois

You have done about the best you can. Here in zone5 not too many are cane hardy. There are roses that are tip hardy here of course. I used to have more cane left but not after these last two winters.

A lot of knockouts are sold grafted as it is faster to mass produce. So if that grafted area was not buried then your Knockout will have died in the winter weather. Most likely you will see root stock come up. Sad to say but most grafted roses use Dr. Huey root stock which really doesn't grow well here. Multiflora root stock is recommended. But then since most rose growers in the area don't know to bury the graft I shutter to think of how much more multiflora would growing here. Any questions just ask.

    Bookmark     June 16, 2015 at 9:12AM
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seil zone 6b MI

She's is lovely who ever she is!

    Bookmark     June 16, 2015 at 9:10AM
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michaelg(7a NC Mts)

The brownish leaves are healthy new growth. Again, you should expect to find a color contrast between emerging and established leaves.

    Bookmark     June 16, 2015 at 8:47AM
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seil zone 6b MI

Those are still growing. On blind growth you wouldn't have those redder new shoots coming. The cane would simply end at that last set of very green leaves.

    Bookmark     June 16, 2015 at 8:53AM
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nanadollZ7 SWIdaho(Zone 7 Boise SW Idaho)

Perfect photo and beautiful rose, Sara. Diane

    Bookmark     June 16, 2015 at 12:16AM
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fragrancenutter(Zone 10b)

Nice one! My FP is only 1 year old and it was quite stingy with the flowers in the first year and the colour is not as intense as yours.

    Bookmark     June 16, 2015 at 3:08AM
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jjpeace (zone 5 US/zone 6 Can)

Good to know about Sunsprite's bloom longevity, cjrosaphile. I sort of regret not buying it this year because my eye was only on Julia. I also chose Lightkonigin Lucia instead which has a similar colour as Sunsprite. Beside Julia, I have to say Golden Celebration and Teasing Georgia as it does well in my climate. I really wish I could say the same about Graham Thomas. I love this rose bloom but it is not profuse in blooms or vigorous.

    Bookmark     June 15, 2015 at 7:30PM
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cjrosaphile(z8 Pacific NW)

I can understand why your eye was only on Julia, jjpeace. Just got Golden Celebration and it is like a climber, lots of bs and moderately fragrant unless it improves with age. It's on the fence for me unless you can tell me its worth keeping.

    Bookmark     June 15, 2015 at 8:34PM
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jasminerose4u, California(9b)

Ha, ha, Bill. Glad you ended up liking it. Hope your obelisk turns out well and that you post pictures for us to see.

1 Like    Bookmark     June 5, 2015 at 9:37PM
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sultry_jasmine_nights (Florida 9a)

Mine is now 3 feet tall and started to put out a bud but one of the chickens (I think) bit it off grrrr. It is going gangbusters. It has been in the mid nineties F here and it hasn't even blinked. I think it likes it hot. I am planning to pair it with a Laguna rose that is about the same age and height (so far). I think I will need a really huge arbor lol.

1 Like    Bookmark     June 15, 2015 at 3:00PM
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Devi Viswanathan

Many Thanks to both of you! I loved all the pics!

Cynthia, My god - you have such gorgeous colors there that I am searching for space in my garden for more than just one additional rose. I tend to be more attracted to the dark coral ones - Like the buck rose and the coral drift - will definitely look them up. I have 'vavoom' (floribunda) and 'bewitched' (hybrid tea) near the spot where i am looking to plant the new rose - so thinking that the color 'Sweet Fragrance' or 'Anna's Promise' might look similar - although they are absolutely beautiful! Here's my vavoom

Once again, thanks for the lovely pics and the time!

-Devi

    Bookmark     June 12, 2015 at 8:55PM
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nippstress - zone 5 Nebraska

Happy to help, Devi, and glad you liked the pictures! We're always happy here to enable other gardeners to get more roses. Only ONE coral rose?? Bah - you need several, obviously (smile). Your Vavoom looks terrific, but I'm surprised that it's such a muted apricot color. It has a reputation for being a knock-your-socks off vivid orange, but that could vary with weather too. Regardless, it'll be nice to partner it with another vivid colored coral rose. These are not necessarily all floribundas that I mentioned - several are "shrubs" - but they bloom frequently and are disease resistant.
If you're worried about color clashes, you could always put a contrasting color between the roses. I have white/cream and burgundy as "filler" colors with my apricot roses, and I think apricot and lavender look nice together as well. Let us know if you need additional suggestions (who needs that grass, anyway - eh?)

Cynthia

    Bookmark     June 15, 2015 at 1:20PM
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steve_gw

We rarely get rust here in SE WI, usually only during severe hot dry conditions, unless it came on potted plants that were shipped to our area from a distant location.

    Bookmark     June 14, 2015 at 11:50AM
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nippstress - zone 5 Nebraska

I agree with Steve. It's unusual to get rust in our regions, unless you have a particularly susceptible rose. With nearly 1000 roses, I may have seen it once in 10 years. This has been an extraordinarily wet spring and early summer, so diseases that aren't typical can crop up from time to time. Just hang in there and wait for more typical temperatures to hit.

Cynthia

    Bookmark     June 15, 2015 at 1:05PM
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view1ny NY 6-7

Best of luck. I hope that your daughter has a positive outcome and is back to being herself very soon.

    Bookmark     June 15, 2015 at 4:53AM Thanked by Sara-Ann Z6B OK
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nippstress - zone 5 Nebraska

That's at least good news to know what it is, so that you can start to manage it. You've gotten some great feedback from other folks dealing with thyroid issues, so that's encouragement that it can be managed. Sympathies on the need to do so, but information is always better than the unknown.
We'll keep you both in our prayers.

Cynthia

    Bookmark     June 15, 2015 at 12:38PM Thanked by Sara-Ann Z6B OK
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SoFL Rose z10

Dang. That sounds like so much fun. I'm sorry to hear they won't be having them anymore.

    Bookmark     June 15, 2015 at 11:01AM
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summersrhythm_z6a

There are not many people growing roses in my neighborhood, people are getting so busy with work and other things......and getting cheap too since all other things in life cost so much (like health insurance). I had an older couple came up to me one day, they asked if I could give them some roses (plants) since I had so many. People just don't want to pay the market prices for roses, things are getting expensive...... I hope Wayside Gardens (JP) is doing OK. I love all the DA roses I ordered from Wayside Gardens (same company as JP) this year.

    Bookmark     June 15, 2015 at 11:52AM
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nummykitchen(Z5B)

Thanks guys. We've been having these intense thunderstorms with downpours so much lately. We woke up to another one this morning after one last evening and a few last week! I just keep telling myself that all this rain is good for the roses in the long run but it's ruined a ton my my first blooms of the season before they even open up, guess I will have to wait til we get some new buds.

    Bookmark     June 14, 2015 at 6:39AM
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vasue VA (7A Charlottesville)(7A Charlottesville)

Just for curiosity & to be on the safe side, might clip a discolored bloom into a ziploc for observation. Same weather here recently, also thought rain damage. Yet bagging showed thrips leaving trails inside the bag, which fogged up when brought into the cool house. Taken back into the sun & looking through a magnifying glass, could see hordes of thrips swarming in the bag. So - you never know until you actually check it out. (If bagging suspect buds &/or blooms from more than one plant, keep only one rose's flowers in each bag. If you mix them together, won't be able to tell which plant has the problem otherwise.)

    Bookmark     June 15, 2015 at 8:58AM
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arlene_82 (zone 6 OH)

I agree, much more sun is probably what my Julia needs since that spot probably gets less than 6 hours per day. What looks like grass at the base is actually creeping phlox, which is rooted about a foot away and I cut it back each year, but it does like to grow back in her direction. It's also a raised bed which probably doesn't help either. I have a sunny spot reserved for her in front of the house, and I do believe she will moving this fall :)

    Bookmark     June 14, 2015 at 11:54AM
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cleangeek(Zone 9)

Getting back to humidity: if you live in a humid area you still need to water, humidity doesn't effect the roots. Plants get most of their water from the roots.

Always use the finger test no matter where you live: stick your finger in the soil up to your knuckle, if it's dry then water. My grandparents were farmers(who lived in the humid Midwest) and taught me that trick when I was a child.

    Bookmark     June 15, 2015 at 8:37AM
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Trisha Spare

Thank you all so much for this valuable information!!!

    Bookmark     June 15, 2015 at 6:40AM
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diane_nj 6b/7a(6b/7a)

No, chemical fertilizers don't cause blackspot. A weak plant can be more succeptible to an outbreak.

OK, thanks! I know a lot of rose growers in SE PA, from Chambersburg to Philly. The fungicide that Meredith_e provided is one that has been successful for many people. Make sure to get this specific product and not one of the combination (fungicide/insecticide/fertilizer) products. It is best to start early in the season, but the Bayer fungicide can help with stopping the progression of the blackspot infection, and help suppress future outbreaks.

seil's guidance on handling insects is spot on. Also the note on determining your tolerance for blackspot, and whether the plant defoliates (loses all of the leaves) or not.

Sorry if we seem like inquisitors, but the info was important for us, as what might be useful in SE PA might not be in NE CA. :-)

    Bookmark     June 15, 2015 at 6:55AM
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Missy, Traverse City, Mi Z5

Thanks for the info, everyone. . Seil, I had not sprayed them with anything until now. I sprayed for Mildew today, hope it solves the problem.

    Bookmark     June 14, 2015 at 8:21PM
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jasminerose4u, California(9b)

Looks like you have a Hoverfly (scroll up) in your photo, also known as Allograpta obliqua. The larvae eat aphids and thrips. The adults are important pollinators.

    Bookmark     June 14, 2015 at 9:46PM
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seil zone 6b MI

That plant is not getting enough water or nutrients. It looks like there's been some kind of root damage. Do you have moles or voles or anything the burrows and eats roots in your area?

    Bookmark     June 14, 2015 at 6:29PM
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