Thuja, up until last Monday night, we had only 0.04 inches of rain in 4 weeks with temps in the 90's about 1/3 of that time - storms a couple of miles away several days with good soaking rains for them, nothing but wind, thunder here. All of my in-ground Phyllostachys (some less than others) have been curled up tighter than ....something that is curled up REALLY tight...I know what type of weather you've been having as well and I do not think that you can do anything to prevent the curl, nor should you worry too much about it. Mulch and watering certainly help but curl happens...

My 5 gallon moso that's been in the ground 2 months curls when in direct sunlight. I water it every day too.. I guess it's just normal.

I have the same problem with my plants that get full sun most of the day. I do have some Ph. atrovaginata that is planted next to a redbud tree and is only about 3 feet tall that does not have this problem as much. We got an inch of rain about two weeks ago and the temps get into the 90s everyday. I water every other day.

I tried wilt-pruf last month to help it conserve water. It did help, but a lot of the leaves that I treated got dark brown on top of the leaf. I don't know that this was directly a result of the application or perhaps over-application of the wilt-pruf however.

I tried misting some of my Ph. rubromarginata one hot day and burned a lot of the newer leaves. They were white when I checked them later that day. I won't be trying that again.

I notice that my Y. Anceps does that in the middle of the day... it seems to 'bounce' back every evening.

My Ph. rubro and nigra "folsum black" do that in full sun and 95F.

The rubro also has its tips singed, just like your photo. I guess "temperate" bamboo ain't too thrilled to be in hot Texas summer.

In the last 6 weeks of drought, I had to water every two days to keep the bamboo leaves open.

OTOH, my "tropical" B. tuldoides is completey happy and handsome and shooting like crazy.

Finally got some rain here and things look much better. Amazing what a nice rain will do.

I haven't noticed leaf burn from misting plants in hot weather, even using cold water direct from the hose. I wonder if it could be the chlorine or other minerals in the water that would cause that? Maybe Wilt-pruf was a problem too with leaf burn. I've never used that but thought it was meant for winter use. I know that you aren't supposed to use oil spray during high temperatures.

Same here with Bambusa: no leaf curl. I have a few Dendrocalamus seedlings. The D. strictus never curls, but 1 of my D. calostachys curls in the heat while another does not. Maybe it's due to root/rhizome systems but looks to be mostly genetic.

I suppose I have my plants spoiled too much and should water every other day instead to encourage deeper root growth. I find myself watering almost automatically when I see leaf curl. Thanks.

Leaf curl is the plants response to low soil moisture, low humidity, high temperature. I allows the plant a means of reducing leaf surface area and water loss. A mist nozzle would help.