Black spot problems on roses...........

[LovetoLearn]

Well, I tried all I could do on my roses but every one of them succumbed to black spot almost to the point of death.

They had absolutely no leaves left and very, very few flowers. So, after trying all of the organic sources that I could find, I had to resort to Rose Pride (yuck!) but it did work. My Heart O' Golds and Tamoras have come back with a vengance even after the 15 inches or so of rain that we had gotten here on the Gulf Coast in the past several weeks.

I would love to go back to organic on them, but, since they are not an edible plant, I will stay with Rose Pride for now.

Anyone ever had this problem? I know many people have, especially here on the coast and that the cause is high humidity but surely there are some more drastic measures that I can take to save them, organically I mean.

[Nadine]

There is an organic way to treat black spot.

You do not mention the organic methods you tried on your roses. In addition, knowing an approximate location would be helpful. (Florida? Houston, TX?) Providing this information would be useful in determining possible issues. :wink: Regardless, I believe you will find the following helpful. I found it by doing a search on the main part of the website.

Cheers,

Nadine

http://www.dirtdoctor.com/view_question.php?id=228

Common name of fungal leaf spot that attacks the foliage of plants such as roses. There is usually a yellow halo around the dark spot, then the entire leaf turns yellow and ultimately die. Best controls include selection of resistant plants and the use of baking soda spray. Severe cases cause leaves to drop. Plant resistant cultivars, and compost all dropped leaves and trimmings. Mulch bare soil to prevent dirt and spores from being splashed up onto plants. Apply horticultural cornmeal to the soil and spray Garrett Juice with potassium bicarbonate.

[LovetoLearn]

I live about 60 miles South of Houston, about 5 miles from the beach.

I have selected roses, such as David Austins' Othello and Tamora and then some other cultivars such as Heart 'O Gold and the dreaded Double Knockout rose(which I am not very fond of) just to see if any of them would work.

Some, such as the Othello and Tamora, were supposed to be COMPLETELY disease resistant, yeah right. :(

I love roses but without drastic measures I might as well just have a burning ritual and never buy a rose again. It might sound like frustrated, angry talk but I have worked sooooo hard on them and nothing works, beyond chemicals I mean. I have tried the cornmeal juice thing until I am blue in the face, with and without Garrett Juice, etc.

My roses are usually beautiful for about six weeks after planting and as far as all the books and literature say, I do things right. I buy plants from reputable vendors such as David Austin himself, purchase and receive them during the winter, which is not all that cold here on the coast. I plant them around December. By spring, March and April here, they are gorgous. By the end of May and beginning of June, they are practically dead.

I am quite convinced that it is not the soil. The symptoms are the exact symptoms of Black Spot, gradual yellowing turning into drastic yellowing and black spots the size of half dollars, and then..............about 2 weeks later the roses look like toothpicks sticking out of the ground.

I have not tried baking soda yet but when I do, and I will, it will have to be strong and drastic.

:cry: :cry: :cry: :cry: :cry: :cry:

[Nadine]

Are these heirloom roses? Are they adapted to your climate conditions? That is a huge factor in success with roses.

When you do try the bicarbonate, try to find some potassium bicarbonate instead of sodium bicarbonate. From what I have been told, it is better on the plants and the soil. Keep using organic methods please.

To use a chemical can set you back quite a bit and I do not like to hear people getting frustrated with the natural way because the organic way does work. How else would this world have survived for thousands and thousands of years?
:wink:

[goo0h]

When I bought this house it came with an antique (?) rose bush along the South wall. The original owner indicated some chemical I should use to keep it healthy. The first Spring it got black spot really bad. I used this prescribed chemical to no avail. The leaves did just what you're describing.

Then I read (on another forum actually) how David Hall of San Antonio tried sprinkling horticultural cornmeal around his roses and how black spot no longer became an issue.

OK, so I decided to go drastic. I figured I didn't have much to lose since the plant looked so sick. I pruned back all the areas that looked sick, then started a regimen of sprinkling a little bit of horticultural cornmeal around it every month during the blooming season.

Well, the results were so dramatic that it switched me over to organic for good.

As I've commented on this forum before, personally I've never had any luck with cornmeal juice. Perhaps my juice making skills just aren't sufficient. Who knows. However, cornmeal on the ground does work, and yes this fungus, like all fungus problems, originate from the soil.

When my crepe myrtles get powdery mildew--another fungus--cornmeal on the ground tends to help, but not always completely. In this case what I have found tends to work best for me is to spray: 2 ounces apple cider vinegar (yup, that's a bit on the strong side) + 1 ounce black strap molasses in a gallon of water. Make sure to use apple cider vinegar and not apple flavored vinegar. Also make sure to not spray this in the full heat of the day, obviously. This solution just washes the powdery mildew completely off. A couple of days later healthy green growth pops out beyond the area damaged by the fungus.

I've also used this mixture on my rose bush leaves if they weren't looking too good, but generally the cornmeal is sufficient for this plant. This solution is a bit harsh on the blooms, though.

Just out of curiosity, what sort of grass is in your lawn? Is your roses near this lawn? I found the article in the recent issue of "DIRT" on lawn allergens very interesting. According to the research being done by this guy in Dallas, Bermuda grass has a tendency to harbor more fungus than St. Augustine. Now this study was focusing on fungus/molds most responsible to allergies/astham, and I don't know how these very same fungus/molds relate to other problems like black spot or powdery mildew. Still, can't help to wonder if that bloody Bermuda in the back yard (I have St. Augustine largely in the front) is a contributing factor to the fungal problems of my rose bush and crepe myrtles. Hmmmm.....

Anyway, hope it all gets worked out.

[LovetoLearn]

Nadine wrote: Are these heirloom roses? Are they adapted to your climate conditions? That is a huge factor in success with roses.


I have several different kinds of roses including 2 types of David Austin roses.....Tamora and Othello. David Austin roses, from what I have read, are almost exclusively cool or cold weather roses, but, I did alot of research on their site and bought only roses that they said were aclimated to this area.

Heart 'O Gold is also supposed to be great in this area and, if I am not mistaken, I bought them from one of the following Heirloom, Edmonds, Teas or Weeks roses, I forget which but it was one of them. If I am not mistaken, all of those vendors are very reputable.

My Double Knockouts were purchased from the local Home Depot as they are a very popular rose to be carried in this area. I never really expected the Knockouts to do to good especially coming from Home Depot but they have not done any worse or better than the others.

Nadine wrote: When you do try the bicarbonate, try to find some potassium bicarbonate instead of sodium bicarbonate.

I have replaced the Rose Pride in my sprayer with Sodium Bicarbonate, for now, until I can get some Pottasium Bicarbonte. I will try the SB this week but have read that I should be particularly careful NOT to get it on the soil as it could damage the roots of the plant. :? :? :?

Nadine wrote: To use a chemical can set you back quite a bit and I do not like to hear people getting frustrated with the natural way because the organic way does work. How else would this world have survived for thousands and thousands of years?


I have, wholeheartedly, gone organic (ok, so maybe the Rose Pride thing was a major messup :wink: ). I have horticultural cornmeal, corn gluten meal, alfalfa meal, blackstrap molasses, 10% apple cider vinegar, Garrett Juice, Fish and Seaweed Emulsion and just about everything that I could possibly use to go organic. But, like you mentioned, it does get very frustrating and I do not want to lose every plant I have before it starts working. :(


goo0h wrote: Then I read (on another forum actually) how David Hall of San Antonio tried sprinkling horticultural cornmeal around his roses and how black spot no longer became an issue.


This is a very interesting concept. My thoughts were that the cornmeal would actually spread any diseases that are already there. Seems like the Corn Gluten Meal might work better because of the properties of not letting new growth form.

The areas under my roses are mulched albeit pretty thin. I could improve that.

goo0H wrote: Just out of curiosity, what sort of grass is in your lawn? Is your roses near this lawn?

My whole lawn is St. Augustine while my neighbors on both sides have burmuda.

My lawn is not in very good shape either. I have put horticultural cornmeal down twice on the schedule recommended by the Dirt Doctor but it does not seem to have had any effect. As the matter of fact, almost every house in my neighborhood has great, green, thick grass except mine. Mine looks more dead and thin than anything.

Some bare spots that I had last year have filled in but the grass stays low and does not thicken up. I stopped watering the lawn very much, if at all, for the last several months to try and get the grass to sink its roots deeper into the soil but it seems to have caused the opposite effect. The grass that I do have grows in sheets on top of the soil and you can grab a handful and tug on it and about 2 square foot area will come up, in a sheet. So, while I am the only one around here trying to be totally organic, my property looks like the worst abuse of plants of the century while my neighbors yards look like lush green jungles. Our subdivision is only about 10 years old with my house and property only being 5 years old.

I am going to try my best to stay organic, but as of right now, it is like a bomb dropped in my yard and yes, it is very frustrating. :cry: :cry: :cry: But I will keep trying.

Maybe it would be better to just have flat soil with no plants, it would be alot less frustrating.

I wish one of you were here to see what is going on and make sure my diagnoses are correct.

Ok, I am off of my soapbox now. Sorry.

[pakin]

I've not read every word of the above, but I get the gist of it and know how frustrated you are.

I've decided that I don't start spraying my roses early enough. Two things I plan to do next year is (1) to be sure to prune the roses and (2) try to prevent the problems before they happen.

Pat Akin

[goo0h]

LovetoLearn wrote: This is a very interesting concept. My thoughts were that the cornmeal would actually spread any diseases that are already there. Seems like the Corn Gluten Meal might work better because of the properties of not letting new growth form.
Corn GLUTEN meal (CGM) has no fungal-stopping qualities. CGM is used to help prevent seeds from germinating, and it's typically put down just before weeds go to seed. (Though I have yet to be successful to precisely coordinate with Nature on such an application. :wink:) CGM is also a strong protein source for nitrogen, so is sometimes added to some organic fertilizers. (Examples at http://bluebonnetfarms.com/products.html )

Horticultural cornmeal acts as a fungicide. Actually, if I remember things correctly, cornmeal promotes the growth of a beneficial fungus, one that wraps itself around the bad fungus and destroys it. It too will also break down to provide some nitrogen to the soil, but not that much.

LovetoLearn wrote: The areas under my roses are mulched albeit pretty thin. I could improve that.
And when you do, put down some horticultural cornmeal too.

LovetoLearn wrote: My lawn is not in very good shape either. I have put horticultural cornmeal down twice on the schedule recommended by the Dirt Doctor but it does not seem to have had any effect. As the matter of fact, almost every house in my neighborhood has great, green, thick grass except mine. Mine looks more dead and thin than anything.
Well, not to pimp Bluebonnet Farms too much, but the last two years I've been using their 6-2-4 fertilizer and my sections of St. Augustine have looked better than ever before, according to my neighbors. That works for me! :wink:

LovetoLearn wrote: Some bare spots that I had last year have filled in but the grass stays low and does not thicken up. I stopped watering the lawn very much, if at all, for the last several months to try and get the grass to sink its roots deeper into the soil but it seems to have caused the opposite effect.
You did this gradually, right? The first time I tried a weekly watering cycle the grass looked like it was going to poop-out. So I went back a bit and gradually extended the period between waterings until it was about a week. Now the St. Augustine part handles it pretty well, even in this drought. The Bermuda gets to looking pretty ragged, but that's in the backyard and I'm not a big fan of that lawn anyway.

LovetoLearn wrote: The grass that I do have grows in sheets on top of the soil and you can grab a handful and tug on it and about 2 square foot area will come up, in a sheet. So, while I am the only one around here trying to be totally organic, my property looks like the worst abuse of plants of the century while my neighbors yards look like lush green jungles. Our subdivision is only about 10 years old with my house and property only being 5 years old.
That might require some discussion on the lawn forum. Grubs can do that. It's happened to my neighbors, but so far not to me. Do you see any grubs or any other bugs? There's cinch bugs, but don't know much about them.

LovetoLearn wrote: I am going to try my best to stay organic, but as of right now, it is like a bomb dropped in my yard and yes, it is very frustrating. :cry: :cry: :cry: But I will keep trying.
Well, as has been discussed before in other threads, some of us have observed a withdrawl period as the landscape is adjusted to organic methods. Though, gradually things seem to kick-in.

LovetoLearn wrote: Maybe it would be better to just have flat soil with no plants, it would be alot less frustrating.
Like the dustbowl days? That may not be very far away for some folks, I fear....

LovetoLearn wrote: I wish one of you were here to see what is going on and make sure my diagnoses are correct.

Ok, I am off of my soapbox now. Sorry.
Try the lawn forum too. I do wish it was easier to post pictures on this site. I think it would help to convey these things at times.....

[LovetoLearn]

Thanks for everyones help.

I will take the lawn questions to the lawn section of the forum. :wink:

Thanks again and sorry that I am so long winded.

[LovetoLearn]

Nadine wrote: You do not mention the organic methods you tried on your roses

Ok, I have put some Sodium Bicarbonate with molasses on the roses, for now, until I can get some Potassium Bicarbonate.

We will see how that works and I will keep everyone posted.

P.S. I thought I was watering everything to a good degree as nothing was wilting or dieing. Well, in the past few weeks we have had approx. 15 inches of rain here on the coast and are expected to have around 10 inches more because of the depression/storm that is currently in the gulf.

To my dismay, my roses have EXPLODED! It is like a showroom! I guess I have not been watering them enough. It is amazing. They are loving every inch of water that they can get. Sounds like I should have planted them in a lake or something. :wink:

[pakin]

My experience has been that once the leaf has black spot, it dies. If this is true, the spraying, etc, will only help new leaves not get black spot.

Good luck, p

[LovetoLearn]

I do agree. My roses almost completely defoliated. But, now that the new growth has started, they are growing, black spot free, with a vigour.

[goo0h]

Wouldn't mind if we got some of that rain. Haven't had rain since July 4th, and even then it was just a spit, really.

[LovetoLearn]

I forgot to mention that when I sprayed my roses with the bicarbonate/molasses recipe, it burned them leaving small dots on the leaves. I guess I could weaken the recipe and try again.

My roses are beautiful now and I do not want to hurt them but I do not want them to get black spot again either.

[Dchall_San_Antonio]

Try spraying in the late afternoon after the sun has gone down some.

You might also try spraying with milk (3 ounces per gallon on your hose end sprayer) as a foliar spray and slight soil drench. There are some new organic "fungicides" this link.