Try an emergency mulching of newspapers and grass clippings and/or compost. Soak the soil for a couple of hours with the sprinkler. Lay down the newspapers (Don't try this in the wind) about 4 layers thick and wet the newspaper with the hose really well (sopping, soaked, drenched - REALLY wet!). Then put about 4" of grass clippings and compost, if you have it. Soak again, really, really well. This should help conserve some moisture at the root level. If they are reviving after watering, I would suspect that there just is not enough moisture available to sustain the requirements of the plants.

One other question. Is water soaking into the soil? If the soil is too hard or compacted, then moisture is unable to reach the roots and the plant is sustaining on foliage moisture. It may help to cultivate around the plants an inch or so down, being careful not to damage the roots. Hope this helps. Any other suggestions??

Shauna

My Joe Pye (Eupatorium maculatum) does this every summer when the heat hits. I pour the water on and still they wilt, perking up when it's cooler or during the shady time of day. And still they live on, grow and bloom.

Shauna, one of these plants has a thick layer of newspaper and straw all around it, but I've only been watering at the base of the plant itself, not the surrounding area altho I've been sprinkling water on the leaves in the morning. I don't dare go out there now and water, but if we don't get rain tonite I'll water all around everywhere. The other plant is on bare ground (sand). I do make sure the water soaks into the soil really good. Thanks!
Pudge--that's encouraging, thanks! Makes me want to cry...oh oh, my tears will perk up the leaves! LOL

I concur with Pudge, I used to grow morning glories against a south wall and they looked like that on hot days too. Did them no harm. But I have read that if a plant wilts (it's a hormonal response as well as lack of water) too many times, I will eventually stunt its growth.

I guess I didn't really mean to infer that it isn't a problem. I've been thinking about installing a soaker hose thru my plants cause, really, it drives me nuts but I'm still constantly amazed at their behaviour. Shauna's got an excellent point about water getting to the root ball.

Could you dig a hole next to the root ball and set in a 2 litre bottle pop bottle upside down with the bottom cut off, then keep that resevoir filled with water so it's constantly providing moisture without getting the leaves wet?

I don't think the roots need water, the ground is definitely moist. It's just the leaves themselves that are giving up their moisture because of all this heat. One day I turned a wheelbarrow on end so it would shade a section of the plant and it perked up. It's too big of an area to shade it all though. This has never happened before, otherwise I would have built a shade of some kind. I'll just keep my fingers crossed the fruit won't be damaged.

Correction: "I" personally will not stunt the plant's growth. "It" will. Haha funny typo.

I wonder if vining plants are more prone to wilting? Just a thought since yours are squash family and mine were morning glories. I've seen my scarlet runners do it too come to think of it. And in both cases the soil was moist.

I think that's a clue, vines are farther away from the roots. Nothing else in my garden is wilted. Interesting. We have some cloud cover now (hoping for rain!) and I just looked out and the squash leaves have perked up. Gardening isn't supposed to be this stressful! :-)

Kim, don't cry on your plants. The salt isn't good for the plants. : )

Shauna

Only a few of my plants droop in the heat of the day & recover in the cool regardless of moisture: echinachea, tomato, rudbeckia, delphinium, leopard's bane, forget-me-not, bergenia, beans. Aw, heck, just about everything except iris, peony & marigold. Are you sure that's not normal?

I see visions of little and big umbrellas in my garden, protecting my treasures. I'm not sure if I just dreamt it, LOL but I may have read of such a thing in some ye olde English garden book! I hope that the last day or two have been kinder to your plants. Good Luck!
Faith

Some plants wilt in excessive heat despite having adequate or more than adequate root moisture.
This is caused by transpiration. Transpiration is water loss by the plant to the atmosphere through evaporation. It is a mechanism that the plant uses to cool itself. The human body perspires as a means of cooling.... plants transpire.

In a plant, the moisture is drawn up by the roots, through the plant stem and lost through tiny pores (called stomata) in the leaves. The amount of water each plant loses varies. Some plants have developed ways to reduce water loss while others typically lose great quantities of water. In hot weather, evaporating moisture on the leaf surface serves to cool and protect leaf tissues. Plants with soft, lush foliage will lose huge amounts on very hot days. The amount of leaf surface increases the water loss. That is why vines or plants with big leaves often seem to wilt the quickest. You oughta see what happens to those big leaved Ligularias in the heat!

Most of our garden type plants lose over 95% of the water they take up through transpiration. The average tomato plant will transpire about 136 litres of water in a growing season.

Assuming the root zone has plenty of water....the problem is not the wilting plant. The problem is the excessive heat. Wilting is a sign the plant is working really hard to protect itself... it is trying survive.

So....the moral to the story? Even with plenty of root moisture, some plants will wilt in excessive heat.
Jan

transpiration! that's the word I was looking for! In nearly 20 yrs. living here, this hasn't happened for this many days in a row and I was so afraid the plants wouldn't be able to recover. We're getting a break in the weather--rain is approaching. Thank you all for the wealth of information.