Is this sun damage on my roses?

texasfrecklesJuly 18, 2011

I'm having trouble with my roses this summer. I'm in Fort Worth, Texas where the summer is hot, hot, hot and the overnight temperatures are staying in the 80's. Everything in my garden is stressed except the Rock Roses and the Lantana, but I'm worried about my roses.

My roses are in my front yard garden. My house faces due east and the roses are on the south east portion on of the garden. They get no less than eight hours of full sun each day.

I try not to get the leaves of my roses wet when I water them, but one day a couple of weeks ago, we had a freak rain shower in the middle of the day. the rain lasted about 15 minutes and then the blazing sun came back out. Could that have caused this damage to my rose bushes?

This is one of my Knock-Outs. Sorry the photos are so large, but I thought it would help being able to see the leaves close-up.

Another Knock-Out.

This is my white Knock-Out which I moved in the spring. On top of the dead leaves, it's turning yellow.

I'm going to be devastated if I lose this one. It's a Souvenir de la Malmaison I planted this spring.

This one is my Duchess de Brabant. This damage looks different to me. Is that Black Spot? It's the only one with this type of damage.

I'm a new rose gardner so any advice at all is appreciated. If it's sun damage, should I rig up some type of shade cloth? If I use a shade cloth, how long do I leave it up? Do I need to remove all the damaged leaves? If so, do I remove the entire leaf or just the leaflets that are damaged? Do I need to provide some type of fertilizer for the one that's turning yellow?

Sorry to have so many questions, I just don't want to lose my roses!

Thanks so much!


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IMO its sunburn. I have a few doing that in my back yard at my grooming shop. Increase the water going to them. they need more water in this heat. The sun will still damage the leaves, but it will be less stressful if they are well watered. DEEP watering, not just on top. I increased my drip system to twice a day, 45 minutes each, instead of an hour a day once.

    Bookmark   July 18, 2011 at 9:27AM
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dublinbay z6 (KS)

If you have the patience, you can pluck off any obviously dead leaves (brown leaves), maybe even some of the damaged leaves that still have some green on them, if they look too bad. All that is cosmetic, of course, but it might make you feel better.

Other than that, all I can advise is to follow parti's advice above.

Good luck.


    Bookmark   July 18, 2011 at 11:23AM
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I do have some burlap covers over some of my ore tender (or young, or recently transplanted) roses ate home including the ones I just got from Cliff. No burn on any of those. the ones at the fenceline without protection have those burn spots. Nothing to do cause I am not tenting 100 roses (or more).....just the ones that need it to survive. Bands, newly planted ones from Cliff and a couple of my new bare roots. My Grandma loaded me up on potato sacks! LOL Good thing too cause Cliff opened up some Hybrid teas.....and I said I wasnt gonna look! This year the sun and heat are overbearing with no relief in site.

    Bookmark   July 18, 2011 at 12:10PM
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michaelg(7a NC Mts)

Had you fertilized shortly before this episode? Fertilizer of any kind can reduce the plant's ability to take up water, and too much nitrogen can directly burn foliage. There was probably some sudden loss of hydration. (I assume you haven't been spraying chemicals.)

I'm pretty sure the rain shower had nothing to do with it.

    Bookmark   July 18, 2011 at 12:13PM
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I got that kind of damage a couple of weeks ago - on roses, and many many other plants. It had been amazingly cold (low 50s) and rainy, and it went from that to 95degrees in 48 hours. The plants had all been in "got to get more light" mode, and suddenly it got so hot hot - sun damage was the result. I think they are better able to protect themselves if the heating up is gradual.

Anyway, the good news is that it isn't a disease, and your roses appear to be putting out healthy new growth - just cut off the damaged leaves (or not).


    Bookmark   July 18, 2011 at 12:15PM
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Looks like sunburn to me. I'm in Phoenix and that's what happens to my roses every summer when we're in triple-digits for weeks on end. Shade cloth helps ward off the worst of it. Taking off the dead leaves - even a dead leaf casts shade and it's the canes you want to protect. Leaves come and go every year.

They say you can't burn a leaf by watering during the heat of the day. I try not to argue with experts and hosing down a hot rose bush will cool the air and soil around it.

Since so much of the US is experiencing the blast furnace heat we encounter year after year, I would adjust your gardening practices to mimic ours while it's so hot. You can expect fast-blowing blooms, no scent, some dormancy, a lot of dead leaves and weird cane and leaf discoloration. If the leaves were already stippled from a pest or disease, those leaves will be worse than the newer ones.

Increase water; decrease nitrogen substantially. Nitrogen in warm soil will release faster and that new growth will burn and be stunted. Better to have a healthy underfed bush than a well-fed one stressing in the heat. Mulch heavily and water frequently. We don't have a great deal of blackspot here but I'm guessing a bush that defoliated with it and has no new growth is going to suffer badly in triple-digit heat.

Seems weird to see both two weeks of freezing temps down here this past winter then see it hotter in KC than Phoenix.

    Bookmark   July 18, 2011 at 1:57PM
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Thank you for the advice. For the last few days (before 8:00 am and after 8:00 pm, the only time I can work outside because it's so hot), I've been installing a drip irrigation system. I put adjustable drippers on the roses and have them set to .5 gph. I've been running it for two hours each morning. Does that sound like enough water? I can turn the adjustable heads up to 10 gph, and anything in between.

Our forecast for next week is 103, 104, 104, 104, etc. It's crazy hot. My next project is to get a shade cloth fixed up before next week.

Thank you again for the help!

    Bookmark   July 20, 2011 at 10:56AM
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michaelg(7a NC Mts)

7 gal. per week sounds like an appropriate amount if you want to try to keep the roses in active growth. Some would say you should be giving that in larger doses at less frequent intervals, but I have experience neither with drip nor with > 100 temperatures.

    Bookmark   July 20, 2011 at 12:38PM
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hoovb zone 9 sunset 23

Also get out there and feel around with your hands that the entire area around each plant is actually getting moist. Drip systems are awesome, but every once in a while it is wise to make sure they are working as intended. They can clog, a critter can bite through a line, the lines get moved accidentally, etc.

    Bookmark   July 20, 2011 at 6:26PM
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sabalmatt_dallas(Z8 Dallas)

Looks like sunburn and heat stress to me- many of mine look the same. I have been watering daily to every other day to keep them hydrated.

    Bookmark   July 20, 2011 at 7:45PM
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When I went to twice a day watering my roses took off like mad. All are b looming again and they are putting on new canes and new foliage. My leaves look awful on most of my plants right now from heat, but the new growth is coming in nicely and they are doing much better having had their water increased. Twice a day for an hour, at 1 gallon drip rates.

Yesterday my yard guy came in and told me that the line in the back of the shop was leaking, so you do need to check. the end of the line plug had come loose and water was just pouring into the jasmine (which it needed BTW). the roses had to be watered by hand as a result. :)

    Bookmark   July 21, 2011 at 7:46AM
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seil zone 6b MI

I might wait to strip the dead leaves. Even though they are dead and not providing nutrients to the rose they are still providing some shade for the canes. If you strip off the leaves the canes may well burn instead. They will eventually fall off on their own when the rose begins to push out new growth anyway.

    Bookmark   July 21, 2011 at 6:41PM
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