Bump.

I don't know the answers to all your questions, but I do know I quit growing Knockouts here in hot, humid NE Alabama because they did blackspot if I didn't spray them. Almost all roses spot in our humidity, and I tolerate it on many, many roses I love...but wasn't going to grow a common Knockout that needed spraying to stay healthy. I didn't have trouble with flower production, though, so maybe yours is another issue other than just high humidity. Hoping someone from your area will see your question and respond.

I hope someone from FL can give you some help. I can be of no help as I have little knowledge concerning Fl growing conditions. The only thing I can think of to add is that black spot leaves usually turn yellow then fall from the bush. Good luck you seem to be doing a fine job with your soil.

What Christopher said.

Jackie

You always hear to grow the teas, noisettes & Chinas in the Southeast. They are charming and grow well, but most will blackspot here, too. Also, depending on the cultivar, they can get very large. The Chinas (especially the red ones) seem to be the most disease resistant for me and generally don't get as big as the teas and noisettes. Rose Petals Nursery should be able to tell you about disease resistance and size expectations for the roses they carry.

I just bought quite a few from Rose Petals. Cyd is very knowledgeable and roses are her passion. I planted a pink DKO a few months ago and it is growing like gangbusters, blooming constantly and is clean. My mom grows them up in the panhandle, in mostly shade and hers are doing great. I just don't know what to tell you about yours. I am sorry they aren't doing well.

Thanks for the suggestions about other varieties, but I already bought and planted all the Knock Outs so don't want to rip them out just to take a chance on something else that may black-spot also. And 18 to 20 rose bushes can be costly. These Knock Outs grow all over Ocala with no one spraying them. They have an excellent reputation for thriving here. Why these are getting diseased is a mystery to me. In NY and TN all the roses commonly grown either were sprayed constantly or succumbed to fungus diseases. Tea roses were the worst. Florabundas and all the climbing roses a close second. I had given up on roses years ago because of the need for spraying. It was the disease free reputation of the Knock Outs that encouraged me to try again. If these die I give up on roses. I'll plant something else across the front of the property.

Greenthumbs, Tea roses are different from and predate Hybrid Teas and black spot less. Noisettes could also be great for you. Rose Petals Nursery is great. I can see it would be very disappointing to have started down the path you did and have this result. In the long run you might enjoy what is healthy in your area. Antique Rose Emporium could be fun to look at on the web and they also have great roses that would look healthy.

Are we sure it's blackspot? Can you post pictures of the diseased leaves? Also, it make take some time before the roses mature and they can resist blackspot. How long ago were they planted?

Greenthumbs photos may help the experts here guide you more.

I hate to admit this, but after reading some of the stories from Florida gardeners here I probably would give up on roses too so I don't blame you at all if that's the way you choose to go.

There are a lot of other plants that thrive without spraying with the heat, sand, salt and humidity right? I have only visited Florida, never lived there, but I remember flowers doing well like canna lilies, gladiolus, day lillies, hibiscus, gardenia and bougainvillea. A lot of people in colder places would love to be able to grow those.

I'm sorry about your roses. That must be so frustrating.

More than likely your disease issues will pass. By the time roses have sat on the sales table they have experienced extreme stress. Under these conditions the most disease resistant plant in the world can succumb. I'm rather sure that they ran out of water a few times before reaching you loving hands.

I would spray long enough to rid them of black spot or what ever disease it is that they have. Then slowly lengthen the time between sprays. Once their roots are mature and they have a chance to adjust. They should be just fine.

As you said knockouts grow fine in your area and yours will also. Give them a little time. While they recover be sure they don't run out of moisture and don't fertilize until they are putting out good strong new growth.

Could it be chili thrips or midge, esp. with lack of blooms? I suggest posting pictures for us to see and taking a sample of the stem/leaves to your county extension office.

AquaEyes 7a New Jersey I tried to grow several you mentioned in TN. Heat and humidity killed them all with fungus and mold diseases. Some actually had their leaves turn gray. All died, were ripped out and burnt. Spraying them had become such a chore let them die. Climbers included. I only bought these Knock Outs because they're supposed to be highly disease resistant. It's hot and humid here in FL, worse than in TN. Cold wasn't the problem in TN either, it was the humidity.

kentucky_rose zone 6 - There is nothing to see since they are green and healthy looking again after a few sprays. The dead and spotted leaves were removed, bagged and discarded.

Patty W. zone 5a Illinois - Good advice. I think I'll wait and see what happens. I haven't seen any more leaves getting those black spots.

Cori Ann- I'm in zone 9a which is north of central FL. The Ocala area. Inland so no sea spray. We can get some real cold nights in winter. They can go into the mid 20s. Most nights are not that cold over the winter. I'm was told this is the edge of temperate and semi-tropical line. There are plants people associate with FL that will winter-kill here if we get a few nights below freezing. Some will kill down to the roots but come back in the spring. I was also advised to buy plants only rated for zone 8 as they are more tolerant to those night time cold freezing snaps we get. I thought that was pretty good advice. Northern zone 9a is cooler than the southern part of the zone. As soon as I get new batteries for the camera I'll take some pics to share here.

Brrrr! Mid 20s? And then you also get heat and humidity later in the year? That's crazy talk! I hope some locals to your area can help you out!

Buford_NE_GA - The diseased leaves were removed to help keep it from spreading so no pics. Sorry. The leaves still on the bushes are a nice green but they stopped growing and budding. I bought them over a period of time. The first ones were bought some time in the fall. They took off like gangbusters as did those rose plants that followed. I'm guessing they were in the ground for about 6 or 7 weeks when I saw the first black spots on the leaves. I found this image online. It looked exactly like this. The last 6 plants were not effected and are still blooming.

Cori Ann - Don't misunderstand. Only the night would drop into the 20s or 30s. The days would be in the 50s, 60s or 70s. And it doesn't happen that often. I didn't think it would get that cold here but it does. It would only be for a night or two then warms up again. At the moment it's 10:16 PM and 67 F. Summers are brutal with days in the 90s, high humidity and sultry nights.

Sheila z8a- Thanks for the info. If these roses don't survive I give upon roses. Unless they could be guaranteed disease free I wont spent more time and money on them. I wanted a attractive windbreak and a living privacy "fence". I saw healthy Knock Outs all over Ocala and that encouraged me to try again. The only roses I ever knew that were disease free were called "Nearly Wild" and sold in one nursery in TN. But that woman died and the place changed hands several times, then closed. She gave us a few for being good customers right before she passed. They were too large to dig up and bring to FL. At that point they had been in the ground for about 15 years. They were the only rose to live there without sprays, fertilizers.... nothing and they never were bothered by insects.

pat_bamaz7 - I would really have to be assured, no guaranteed the rose would be disease free before I replaced these if they die. It's a lot of effort and cost to buy and plant a 150' row of roses in sand. Manure and topsoil has to be mixed with the sand and then the plant mulched and watered. I'm 73 years old, have arthritis and it's plain exhausting. Age unfortunately, catches up to us all.

I wonder if root knot nematodes may be causing your roses to struggle, and thus be more susceptible to disease. Someone else from Florida would be better able to help you if that's the issue.

:-)

~Christopher

This is so hard, green thumbs. More Floridians could pitch in. Mike Shoup at Antique Rose Emporium in Texas and Rose Petals nursery in Florida would give great advice, but I see your point about starting over being so hard. I am 64 now and loving all this action of rose planting, and Diane and several others are mature gardeners. I think getting a great rose going that was healthy would be so good for you, you almost have to do it. Don't think replace the whole hedge. Just try a recommendation from ARE or rosepetals and look toward the future with a plant or two or three. I wonder about a large pot if root nematodes are a problem. We feel for you.

I don't mean to sway you from roses, because I definitely believe you can grow them. That being said, if you are looking for a green blooming hedge, maybe a mixed perrenial hedge would be a good idea or if you want a more homogenous look maybe a shrub such as ixoras would work. It is evergreen, must be easy to grow because they are everywhere, seemingly constantly blooming, healthy and the flowers remind me of hydrangea. They are overused around here, but it's because they are so easy.

https://www.gardeningknowhow.com/ornamental/shrubs/ixora/growing-ixora-shrubs.htm

I have several plants in mind if the roses do die. Boxwoods do good here as well as almost all azaleas. They get full and tall. I took a slow drive around the area (sand roads here) to get a better idea of what other people are using. Most by far have planted azaleas. Some are over 6' tall. I looked at ixoras at Home Depot. Nice plants also and I love their flowers but where I live a little east of Ocala, the freezing nights would kill them. You are over 100 miles south of me. They would most likely survive there. They wont survive our cold snaps.

Zone 9a gets some very cold nights. True tropicals don't do well here or just die off at the first real freeze.

From that site:

Care of Ixora plants in
containers requires re-potting every two to three years. Bring the
shrubs indoors if any frost is predicted. The plants are extremely
tender and will succumb to freezing temperatures.

I wanted to add I just ordered a 10 X 16' greenhouse to house my potted tropicals over the winter. The 2 small 8 X 6' ones are packed.

From experience, the KO roses will get some BS but not like what you describe. A picture would be very helpful, maybe use your cellphone. I stopped growing KO because although it did survive the BS it did NOT do well with the Chili Thrips. If anything, they were magnets for CT.

The location of your KO will also play a huge factor.

Ocala is a great place to grow roses.

I keep reading further on in this thread and it doesn't make any sense to me. You should NOT be having this much trouble. My suggestion (based on the assumption that you bought your roses from the big box stores and that they are grafted on Dr. Huey):

Go to a local nursery that sells roses on Fortuniana rootstock. I noted on the Nelson's Florida Roses site that http://www.gardengatenursery.net/ just got a shipment in on Saturday. Ask them if they sell KO on Fortuniana. If two or three are available, buy them (they are not cheap compared to what you find at Wally-World or Lowes) and test these out in place of your more under performing KOs. If you note a big difference, then your problem, which is common in Florida (especially Central Florida with its sandy soil) is nematoads. Should you still long for the hedge of KOs but need a break on the price, contact Nelson's Roses directly and tell them that you're interested in purchasing...I don't know how many you initially bought...like, 50 bushes and ask for a bulk price (it'll be cheaper than the $20-$25 price you might have paid at Garden Gate). When you go pick them up (you'll need a truck) make sure to ask for Ramon and explain to him what problem you had with the previous lot of KOs. Bring a plant or branch to show him. He will be more than happy to lend some of his advice, and it is very good advice.

Good luck and try not to give up on roses. You live in a great spot to grow roses on Fortuniana rootstock. Unfortunately, roses on Dr. Huey rootstock will NOT live in your area and will decline much like what you described.

Another challenge if ever you go to Nelson's, I dare you to walk off without more than what you ordered, lol.

Good Luck and keep us posted,

-Adrian.

If you got these at a big box store, they have a one year guarantee and you may be able to exchange them (lowes, home depot). Another thing you may need to address is irrigation. If you do not water them regularly, they will become more succeptable to disease. It may seem like they grow like weeds all over town, but that's only well established roses that are about 2-3 years old. New roses need constant irrigation and will only show off their best defense against disease after a few years.

On another note, usually liquid fertilizer is not enough in our sandy soil so try a granular one. It will take time to see its effect but will last much longer than liquid solvable fertilizers.

Take a look at my blog for suggestions on what has done well for me here in South Florida. If it does well for me, it will do wonderfully for you. Getting them grafted on Fortuniana however, is key (unless you make a raised bed with store bought soil, that has worked for me).

www.southfloridarose.com

Oh I am sorry! Well there goes that idea. I love azaleas and the new reblooming ones are great. I had Autumn Angel and Autum Twist in NC.

If you need more shade you could mix some crape myrtles in the border to offer some protection.

kublakan - My spouse and I decided to continue watering, feeding and spraying them with the fungicide I bought. If they die, that's it for roses. They never survived in NY or TN, always succumbed to disease so I was a fool to think these KOs would work for us here in FL. I have no idea where the KOs come from seen all over Ocala but they cannot be the same ones I bought at WalMart. Different rootstock? I don't don't know and at this point it doesn't matter. They have been sitting there now for weeks doing nothing. Not growing or dying. And from what I understand if it is root nematodes there is nothing I can do to save them. As they die they'll be pulled out and something that stays healthy here and needs no spraying will be planted several feet from the spot the dead rose was removed from. Thanks for all the advice. I learned my lesson.

At my age removing and replacing them all with a better KO on different root-stock is simply not an option. And that would have little effect on BS disease.

SoFL Rose z10 - See my reply above to Kublakan. We used both fertilizers at different times and neither had much effect on these KO roses except right after we planted them last Sept or Oct. They are watered twice a week since rain has been scarce here. They were thriving until, like up north, the BS disease showed up destroying their leaves. Though the spray seems to be keeping the disease at bay the plants have made little to no new growth. The soil is sandy but as mentioned above somewhere, a lot of topsoil and cow manure was added when we planted them, making the job harder and adding to the cost. They were doing beautifully until the disease struck.