White Spots on my Rose Bush Leaves

rose bush leavesThe first year I planted my rose bushes late into the season.  They grew and bloomed like crazy.  I had blooming roses into November and North Carolina November is cold!  I loved my plants and they were very happy.

Last year, the second year of my rosebushes, white spots appeared on the leaves early in spring but I saw no aphids, no bugs of any sort.  Next thing I know, the leaves have holes then, in the blink of an eye, the bushes look like they’ve been eaten by locust!  The bushes grew and roses bloomed – once!  Then, after the “leaf decay” no more roses, all season!  Tragic!  rose bush

Here we are in mid April and the white spots are back.  Now I find out, don’t plant rose bushes near the house, they need circulating air.  Mine are by a brick wall.  Rose bushes don’t like warm days and cold nights – the perfect definition of spring in North Carolina. Rose bushes don’t like to be damp – our spring mornings have dew so thick you need boots.  Today I read, “rose bushes are a lot of work, but they’re worth it.”  *Sigh*

So, I researched and found I should cut off the bad leaves and spray with a combination of water, baking soda and dishwashing detergent.  I’ve spent most of the day with the rose bushes. I hope I was in time.

Treatment and Prevention: In its early stages, it can actually be washed or sprayed off the roses, but once it takes hold, this is not possible.One of the best ways to avoid powdery mildew is to keep things as airy as possible. Roses planted too close to a wall or to each other may not get enough airflow. You can prune away crossing canes and open the center of the bush to allow sunlight and airflow, if you have a bush that is troublesome. Also, spraying the foliage with a mixture of 1 T. baking soda per 1 gallon of water and a few drops of dish detergent can be effective. If used as a preventative. Sulpher or lime sulpher sprays can be used early as a preventaive also. There are other more toxic chemicals available, such as copper based poisons among other things, but as with all toxic chemicals they should be used only when absolutely necessary and strictly according to the directions provided witht he product. These treatments as with most anti fungal agents are best applied as a preventative in the early spring or late winter when the plants are still dormant.

Thanks for this information from Bad Fungi.

Another great article came from Rose Gardening Made Easy:

Powdery Mildew On Roses

Rose diseases such as powdery mildew is a fungus that thrives on humid nights and warm or hot days.

The symptom is a white powdery residue on leaves.

The leaves then become crinkle and distorted.

An exellent proven preventative and Non-Toxic treatment for powdery mildew, as well as Blackspot, is to spray with a baking soda solution.

To Mix Your Own:

Mix together 2 tablespoons fine horticultural oil with 1 tablespoon mild dish soap and a large tablespoon of baking soda.

Mix with one gallon of water and stir thouroughly.

Before spraying, it’s best to water your rose plants well and hose down the foilage with a garden hose.

Spray only when the roses are shaded, early morning or evening.

Spray all foilage and the canes comletely.

To prevent powdery mildew from attacking your roses, spray weekly with the baking soda solution when leaves first appear in the spring, then every two weeks thereafter.

This is the proper way to apply the Baking Soda Solution:

To prevent spreading the disease, remove all affected leaves and destroy them.

Water the soil, BEFORE spraying the rose bush and spraying the soil beneath it, making sure you spray the leaves undersides as well on top of the leaves.

Spray all canes, in fact, thoroughly soak the bush with the solution, leaving nothing unsprayed.

The reason the soil should be sprayed as well, is because there are ‘fungus spores’ in the soil as well.

So you want to get rid of those also, to prevent the fungus from coming back.”

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21 Responses to White Spots on my Rose Bush Leaves

  1. This is the almsot same recipe I use to get rid of mould on my cukes and zucchini plants. I use a drip of normal vegetable oil from my kitchen rather than horticultural oil (whatever that is) and it works a treat. I’ve read that the soap and oil are really there to spread the baking soda and make it stick to the leaves. They are not active ingredients. Also, this mix doesn’t actually kill the mould, it just creates an environment that is hostile to mould growth (hence the need to reapply).

    I’d add two comments to your instructions above. 1) First look for beetles. At least in Australia we have a mould eating beetle (the size of a lady bug but yellow and black) that normally appears if you’ve got mould. They don’t like being sprayed so try to knock them off the plant before you go to work. 2) You probably need to reapply the spray after a heavy rain. I’ve found that’s more important than worrying about watching the calendar to spray every 2 weeks. If you check your plants often, they let you know when they need a spray.

    And definitely heed the advice about not spraying when your leaves will be in the sun for a long time. I once ignored that and my leaves were burned and most died as a result (that combined with making the mixture too strong – if a T of baking soda is good, 3 must be better, right? NOT).

    The advice I follow when pruning is to try to form your roses like a basket (cuting back to about knee height when doing your autumn/winter prune) which lets plenty of light and air through the centre. Once the leaves are on the stems and the flowers are in bloom they look very bushy. It’s hard to get used to pruning a plant to look leggy, but it really does work.

    Roses aren’t hard work, you just need to undrestand what they like and spend a bit of time once or twice a year making them happy.

  2. Karen says:

    Laura: Thank you so much for your detailed response!

    And for the heads-up about overdoing it. I followed the recipe exactly though the “if 1 T. is good, how about 3?” thought did pass through my brain. I refrained.

    I have looked at these leaves on numerous occasions looking for aphids. I have not seen any critters anywhere including beetles.

    I sprayed in the afternoon when the sun was on the other side of the house. Wasn’t sure why they said spray in the shade, but I did and thanks for letting me know why.

    Rain is predicted here for the next couple of days so I had already planned to re-spray. I made up a 1/2 gallon of the solution and used about 1/2 of that. I check all the plants practically everyday so I will be reapplying as they seem to need it.

    Now that I’ve cut out all the parts with spots (well, most of them, I keep seeing more..), my plants definitely look leggy. Ugh. Liked them better bushy and full but I can see that the air couldn’t circulate as they were. Bummer.

    My concern at this point is that the articles said, “this treatment should work if caught in time.” I hope I did.

    Love you for all the info! Thanks.

  3. Pingback: Tomato Harvest & mildew prevention | Laura Rittenhouse's Gardening Journal

  4. Susan says:

    Hi Karen,

    I’m just wondering if this solution worked for you? I’m having the same issue with my two rose bushes at the moment.

    Thanks!
    Susan

  5. Karen says:

    It worked when the leaves weren’t this infested. And, it seemed to slow this process once it had taken over.

    Interestingly, we had a very warm spring, not much moisture because the temps were high so quickly, and I didn’t get the white spots at all this year, yet.

    I hope you find something that works for you. This is such an inexpensive and easy treatment to try first.

    Please, keep us posted!

  6. Shail says:

    Thanks you so much for all the tips provided to take care of the rose bush. I hope this works for my bush. This is such an inexpensive and easy treatment to try first bfore applying chemicals. :-)

  7. Karen says:

    Good luck with that, Shail.

    I had no white spots at all this year. I’m guessing that perhaps it was because we had such an early Spring and the bush was in full bloom before the humidity hit? Actually, I have no idea why I had no spots this year!

    Please, let me know how this works for you!

  8. Maria Dorta says:

    Well Hi, I’m new to this group and love all the info you have all shared…thank you. I was wondering why if humidity is bad for the roses how come England is known for beautiful rose gardens and it’s always foggy, drizzling or raining? OK it’s not as hot I guess but still it is very wet and roses don’t like wet. I tried for years to grow roses in Miami…talk about “UP HILL BATTLE,” now I moved to NC and it seems roses are happier here. This is my first year from what you have written next year won’t be as much fun. :} Well lets see….
    Great to meet you all,
    Maria

  9. karen says:

    Hi Maria:

    I think the moisture problem is that we have so much in the morning, then burning sun in the afternoon!

    And, my poor plants have no air flow which is, apparently, very necessary for rose bushes. Mine are between a deck fencing and the brick wall of the house. Wish I’d known before planting!

    Welcome and Thanks for Writing!

  10. Maria Dorta says:

    Hey Karen, I have two rose bushes in pots and now that the weather has cooled they are LOVING it. Summer was too hot for them and the flowers were small now they are coming in large and deep in color…I’m SOoooooo happy. I use Color Burst as a fertilizer and it is awesome. Really enjoy your blog and look forward to the joys in your garden!
    Maria

  11. karen says:

    Maria -

    Glad to know about Color Burst! My roses are outside so they’re almost done for the year (and very small blooms…).

    Enjoy your babies!

  12. sANDY l. says:

    I haven’t heard of Color burst. Does that make the roses bigger.Can u get it at Wal Mart? I’m having trouble with my rose leaves too. On one of my roses, leaves r all gone . I like the suggestion about putting baking soda & dish Detergent.

  13. Karen says:

    Hi Sandy:
    I hadn’t heard of Color Burst, either, and I’m not sure where to get it. Try the baking soda and dish detergent and let us know how it works! I know you will get better results at the first sign of bugs or spots and, now that you’ve lost most of the leaves, it may be best to cut them to the ground this winter and start again next Spring.

  14. CJ says:

    My entire rose bush looks infected. Should I cut off all the leaves leaving next to nothing and then do this? Will it grow back or is it history?

  15. Karen says:

    I would cut it all off.

    It will come back but you may not get blooms again this year, depending where you live and how long your season lasts.

  16. Ivy says:

    The roses in the picture have rose slugs. Use insecticidal soap. http://forums2.gardenweb.com/forums/load/roses/msg0511262214417.html

  17. Karen says:

    Thank you so much, Ivy!

  18. Sandy Wright says:

    I have white spots on 3 rose bushes and small wholes (like something has bitten) little holes on another rose bush, will the mixture of 2 tbls horticutural oil, 1 tbls mild dish soap and 1 lgr tbls baking soda?

  19. Karen says:

    Hi Sandy:
    Please try that mixture and let us know how it works!

    The leaves that are already damaged need to be removed and discarded. Continue to spray for a time as new leaves appear to protect them. I have found this damage happens only on the first flush of my leaves, in Spring. Later in the seasons, this tends not to happen.

    Thanks for writing and, again, please let us know here how this works out for you.

  20. Arlene Barry says:

    Hi. I have just found this site. I am a rather fair gardner. I can grow pretty much anything, EXCEPT roses. I put into the ground on Tuesday (6/3/14) a beautiful tea rose tree. Today, on 6/6/14 most if not all of the blooms have begun to droop then wither. The leaves seem to have the same type of small white spots that you referred to. Is the drooping and withering a symptom of this fungus as well? Thanks so much for your time.

  21. Karen says:

    Hi Arlene:
    The drooping and withering sounds more like transplant shock – very common.

    Do what you can to get rid of the white spots IMMEDIATELY! I’m sure your tea rose tree is gorgeous.

    And, please, keep us posted.

    Thanks for writing!

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