What is affecting this rose bush?

Bleu (Zone 9b - So Cal)

7 years ago

last modified: 7 years ago

This is a Dick Clark rose. I took this photo a few days ago. The plant looked fine:

This afternoon, while deadheading I noticed that some of the new growth doesn't look right:

What is causing this and what can I do to control it?

Thank you.

Featured Answer

Moses, Pitt PA, cold W & hot-humid S, z6

7 years ago

last modified: 7 years ago

Bleu,

Looks like spider mites. Hot, dry weather brings them on. A spray of water from a watering wand, directed at the underside of the leaves done every other day for a week or two should knock them down. The damaged looking leaves will not return to pristine appearance, but the mite population will be pretty much diminished considerably, thus killing off the infestation already present, preventing the infestation from spreading further.

Don't set the water force too strong. You just want to get the leaves' undersides very wet, where the mites live. Do the treatment in the heat of the day, before 5:00 PM when the mites are active, and so that the foliage can dry off before night. Mites hate getting wet. Just getting very wet kills them and wet leaves disrupts their homes. You're not really trying to knock them off, just making their under leaf homes uninhabitable. Mite damaged leaves may prematurely fall off. That is normal.

Alternately, an organic miticide with spinosad as an ingredient can be used. Follow the label directions. Southern Ag Conserve Naturalyte Insect Control, Monterey Garden Insect spray with Spinosad, or Bonide Captain Jack's Dead Bug Brew will work. You can get the premix ready to use spray bottle, or the mix yourself concentrate of each product.

There are conventional, non-organic mite sprays, which I do not think you need to resort to.

Besides hot, dry weather that brings on the mites, roses under stress are more prone to mite trouble, especially if underwatered.

Moses

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Comments (7)

Bleu (Zone 9b - So Cal)
Original Author
7 years ago
Thank you, Moses!

Would neem oil/dish soap work?

I do have Monterrey BT also (I think it's similar to Spinosad?).
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Moses, Pitt PA, cold W & hot-humid S, z6
7 years ago
last modified: 7 years ago
Bleu,

Neem/dishwashing liquid are tricky. Foliage damage risks from the oil. Monterey BT, no. It's a caterpillar killer, not a mite killer.

If you opt to spray anything but water, never spray a dry, dehydrated bush. Foliage damage is guaranteed, even non oil ones or dishwashing liquid. Well watered, well hydrated bushes are the only ones that get chemical sprays. Avoid spraying any chemicals, plain water excluded, when the sun is shining or when the temps are over 80° F.

Moses
Bleu (Zone 9b - So Cal) thanked Moses, Pitt PA, cold W & hot-humid S, z6
Bleu (Zone 9b - So Cal)
Original Author
7 years ago
Okay, I will get the Spinosad.

The rose bush is not dehydrated. Actually, I water it regularly. It survived two awful heatwaves (115F!) and a ridiculously hot July that felt like a 30-day heatwave. The rose is doing well, full of gorgeous blooms. I'm really surprised by this mite attack. But I will follow your advice. Thanks, again, Moses.

This bloom is still on the plant. Gorgeous, isn't it?:
Moses, Pitt PA, cold W & hot-humid S, z6
7 years ago
last modified: 7 years ago
Bleu,

Your Dick Clark is beautiful.

You are evidently a conscientious gardener. Don't beat yourself up. Mites on roses are like fleas on dogs. A dog that never gets fleas is unnatural. The same with roses. Roses probably have small, insignificant mite populations on them at all times, doing negligible damage. It's when the roses get stressed, or when the hot, dry weather comes, which mites favor, that their populations explode to an infestation level.

Moses
Bleu (Zone 9b - So Cal) thanked Moses, Pitt PA, cold W & hot-humid S, z6
ken_adrian Adrian MI cold Z5
7 years ago
many dish soaps are DETERGENT ... much too harsh for the garden .... if used in a heavy amount ....

ken
dianela7analabama
7 years ago
last modified: 7 years ago
I agree they are spider mites. I water my roses deeply every week, and even with suficiente water there are a couple that seem to get spider mites regularly. I spray them with water. Some times late in the evening I also get some regular dawn detergent with water and spray the undersides. Nothing too strong and not during the hot part of the day.
Bleu (Zone 9b - So Cal) thanked dianela7analabama