Gah, powdery mildew

10 years ago

I was trying to preventatively spray my climbing cecile brunners with rose pride this year to prevent another powdery mildew outbreak this year. Then it was looking so nice and happy that I got complacent for a few weeks. Saturday, argh, white film on the leaves. Looks like it's just started, so hopefully I've got it early enough. There aren't any flower buds yet, which is probably good. Last year I was too late and it killed a lot of the flowerbuds.

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Comments (7)

jerijen
10 years ago
That's very strange.

That rose NEVER mildews here in SoCal -- where powdery mildew is one of the primary fungal diseases.

Jeri
jerijen
10 years ago
CaraRose -- Kim's having trouble logging in. He notes (and I had the same thought) that your mildew problem may be caused by insufficient water to the plant.

That is one factor that will cause mildew on otherwise immune plants.

Jeri
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CaraRose
Original Author
10 years ago
I can up the watering, but it's been pretty wet here the last few weeks (wet and cooler temps), I can't imagine that they've been wanting more water. The soil in their bed has been quite damp. I assumed it was probably the dampness that triggered the outbreak. Last year it was the same thing, damp, cool, wet weather in April after an abnormally warm March got everything growing early.

They're quite old, we inherited the house from my great aunt, and we know she and her husband bought it from her sister-in-law and the roses were planted by her sister-in-law. They're probably 60 years old. They hadn't been tended to in years, till I took over the bed three years ago and started to trellis them to the side of the garage.
jerijen
10 years ago
How large are they? Is there any repeat?

I agree that it doesn't sound like they need water -- but I remain astonished that they would mildew.

One of the reasons why "Cecil Brooner" (particularly the climbing form) has always been a stalwart in Southern California gardens is the fact that is IS mildew-proof. no matter how neglected it may be.

Jeri
User
10 years ago
FWIW, rooted cuttings from a climbing Cecile Brunner in my daughters backyard in San Francisco did mildew briefly this spring, along with some other susceptible roses in the yard. I am convinced, however, that this is 'Spray Cecile Brunner' (not Cl. Cecile Brunner), because it is remontant, plus it proliferates and has long leafy sepals (per HMF info).
CaraRose
Original Author
10 years ago
There are about five plants, and I think two are the originals. Those two have a large rootbase. The other three I believe spread from the original and are smaller. There were more plants but I removed some when I took them over since there seemed to be too many too close together. The majority of the long canes are still thinner-- my parents used to just hack them back to keep them from sprawling out into our gangway, so these are growth since I took them over. They're quite long though, some have probably reached 10 feet.

I'm not sure what you mean by repeat-- do you mean do they rebloom? If so, no. At least not at any point that I can remember. They were always prolific bloomers though, even back when they were growing wild and mangled yearly by my parents cutting them back.

When I took the bed over (it's a small strip bed between the gangway and garage), I dug it out and weeded it (it was a mess of nightshade tangled with a knot of rose canes), detangled the canes and pruned out dead canes, then I made a trellis with wire and nails on the side of the garage, and wove the canes onto the wire. I also mulched the bed and fertilized in the spring with a 10-10-10 time released fertilizer.

They grew like mad after that. Since then I added more levels to the trellis. They go up to the top of the garage now. Lots of new growth, and other than the mildew next to no troubles. Last year was the first year I remember them ever having mildew, but it's possible that they did and we just didn't notice the way they were kept before.
roseseek
10 years ago
Immature plants can easily become infected with any sort of fungal issues. Brunner and all of her variants are about as disease resistant as any other rose could hope to be in most situations and conditions. I agree, it sounds as if they don't require more water due to the weather conditions you've been experiencing. In our climates, usually when something as bullet proof as this contracts anything, it's likely due to insufficient water or having been severely pruned. Might these have been significantly cut back in the past year? Removing too much of the wood and foliage mass can also inhibit the plant's immune system due to reduction of food storage and production. Often, permitting them to rebuild that mass helps over come the infection. I guess it is possible that cultivar could simply be prone to mildew due to your conditions (air flow, sun exposure, climate, etc.). It's just one which is not susceptible to any of those issues here in much of SoCal, so it's surprising to hear of it misbehaving elsewhere. Kim