How hot is it?

As our climate has grown to be hotter and hotter, sun-damage to canes has increased frighteningly. In summer 2015 and 2016, our area set astonishing high temperature records.

We have roses which have grown for many years at the foot of our retaining wall -- which we must now propagate, before we lose them. The wall radiates and magnifies heat cruelly -- when the temperature up here is 104 -- it's probably close to 120 down there.

There is so much sunburnt cane, there's no place for the plants to sprout new growth.

I have a couple sufferers here too. Very accurate description of the trouble and I find this type of information very helpful, Melissa and Jeri. Very sad. Thank you.

Jeri, we don't have your awful high temperatures: highs for us are mostly in the nineties, and nights are generally cool enough to be manageable. We do have very long days at our latitude, 45 degrees, and, as I said, no shade whatever. I've never seen these two roses looking like this.

Thanks, Sheila. Shade! we all need SHADE!!

Hi Melissa, can girdlers can affect the plant's ability to push water upward as they interrupt the cambium, the circulatory system of the plant. They eat the cambium, leading to the death of the tissues above their damage. Water stress probably attracts the girdlers as they seem to attack stressed plants faster and worse than non stressed ones. The best defense against sun burn is shade...whether it's from adjacent plants, the specific plant's foliage, temporary structures placed close enough to them to afford relief or trunk paint, such as is often used in orchards to prevent sun scald on the trunks. Any white latex paint should suffice. If the Cl Maman Cochets are receiving irrigation, there are dissolved salts in that water. They build up in the soil due to evaporation and the plants' use and can become toxic very quickly. As the salts concentrate, the foliage color and size as well as the amount and quality of growth are quickly affected, causing the plants to be off color, foliage smaller and less dense and the wood to age more rapidly. Hopefully there is some sort of organic mulch on the gray clay to help insulate it against the direct sun rays, keeping it cooler, reducing surface evaporation and water loss. If at all possible, I would recommend creating berms around the plants to hold water, so it can percolate through the roots to help expel carbon dioxide from the roots; hydrate the plant and surrounding soil and help flush the salt build up from the root zone. Add the insulating mulch layer which will break down, generating Humic Acid, which will help condition the clay, improving its tilth and releasing the salts and other locked-up minerals. You may have to figure out something to shield the canes from the worst of the sun exposure or paint them with the white (or other light colored) latex paint. There are horticultural trunk paints specifically formulated for this use and they may be less toxic to the environment than traditional house paint, but when you are backed into a corner, you have to use what you can obtain. You can also probably figure out some way to use stakes and old bed sheets or tee shirts to provide some sun relief for the affected canes. They might not be pretty, but there are definitely ways to help protect an ailing plant until it can recuperate and overcome what ails it. Good luck!

Kim, thank you very much: that's what I needed to know. About my methods, I don't irrigate, since we have adequate summer rainfall, so salt buildup isn't a problem. I mulch, and we certainly do have a lot of weeds, which, while they're unsightly, do, in lieu of more desirable plants that are still establishing, provide some protection and soil conditioning. I terrace when making planting holes. I've never considered painting the rose canes, but then I've never seen the roses looking like this. Perhaps it's time.

You're welcome, Melissa. I envy your summer rains. Most of my Teas and several of the Chinas were looking extremely heat stressed, though we've only had two days above 84 and they have been consistently watered. We had almost half an inch of rain the other day and you wouldn't believe the difference it made! New foliage bursting out all over and the plants actually looking as if they are going to live, instead of appearing "fried".

Great thread! I envy your summer rains, too, Melissa. Though geographically my area is pretty close to yours, we rarely get any rain worthy of the name in summer. My plants just have to deal with that, once established, because I don't have running water out there,and the water I store up would never, ever be enough to deeply soak all my roses. I have a lot of cane-girdler damage, too. I, too, want to thank you, Kim, for your comments. I've seen how grateful my roses are for being mulched; even without getting any water, they perked right up just having their roots protected from the blasting summer sun. I had no idea that soil berms could be so helpful!!! so, that's another item on my garden to-do list.....making berms.