A picture is worth a thousand words. Any possibility of some images?

I'm really sorry you're having problems with your plant, K. I have to admit that your story is a poser. If you can see no mechanical injury (broken branches, any sign that an animal was responsible), we need to start looking at what is causing the loss of turgidity in the branches & leaves. First, if the well-lignified (real woody) branches aren't drooping and the young branches are, it's most likely a physiological issue, which leads us right back to what's causing a loss of turgidity.

We have to suspect one or two of three things, and any of the three can cause a drought response like wilting. Obviously, under-watering causes a drought response & wilting, so I won't elaborate - sounds like that's not the problem anyway.

Too much water in soil makes water uptake difficult/impossible because of compromised root function due to rot, or to impaired root metabolism as the result of anaerobic (no oxygen) conditions in the root zone.

Too high a level of soluble salts in the soil, which affects the osmotic absorption of water by roots, can lead to wilting. This is usually something that happens gradually, but it can also happen quickly if other issues are at work. If it happens gradually, it is usually accompanied by the symptoms of burned leaf tips and margins. If it happens quickly, it's usually because of a large amount of salts going into the soil - gross over-fertilizing or someone/some large animal using the pot for a bathroom.

You might want to consider what I said and see if anything rings a bell. Also, you need to be able to eliminate herbicide injury. If you reply, you might wish to add info on when last repot was and your fertilizer routine (what used, how much, when last).

Is your plant sitting in a collection saucer? If so, how long was the saucer filled with rain water before you noticed the wilting?

Al

Rhizo and Al,

Thanks much for your observations. I realize it's more difficult to diagnose a plant problem without an image.. I'll try to remedy that if I can move the ficus somewhere out in the open for a better photo. Right now, it's situated under a grove of young live oak trees in dappled sunlight.Container is sitting directly on the ground under the trees. No collection saucer. There was no evidence of poor drainage in the pot after the rain (ie: puddles of water or muddy soil). Last repot was done almost a year ago last fall before I brought the ficus in for the winter.

In reply to your questions, Al: Last fertilizer applied was in late June. Before that, fertilized in mid-March after moving it outside from it's winter home indoors.
Usually fertilize one more time before I move it inside around the end of October. I use 3 TB water soluble Miracle Grow in 5 gal. bucket of water. The watering schedule has been consistent. With temps in the 100's + for the past 65 days, it was necessary to hand water all my container plants at least every other day (the small containers had to get water every day). The foliage on the ficus in question is dark green and shiney. New leaflets emerging on the tips of branches are bright green. No visible change in the plant was noted until the morning immediately after the heavy rain storm. The well lignified branches (four central trunks-)each one inch in diameter were also drooping to the ground; but no broken branches. Last but not least, because the ficus almost completely fills the large container...there's not even enough room for a cat (much less a larger animal) to do his business inside the pot.

This was an overnight occurance which is what makes it seem so strange. Since I may never solve the mystery, my next question might be: What can I do to remedy the situation? Prune, repot, or something else? Thanks again for all your help.

I dunno. I've never heard of a tree that suddenly has lignified branches droop with no sign of mechanical influence (kids/animals, snow load ....), so for now, it's beyond me. Lignified branches don't droop when the plant loses turgidity.

I would tip prune now & nurse it through the winter. In may or early Jun, I would attack the roots, bare-rooting and pruning the unnecessary larger roots out. If you're up for it, I would gather the ingredients over winter so you can make the gritty mix and repot the tree into that when you do repot. I would fertilize (in the gritty mix) every two weeks at full recommended strength while the plant is growing well (early May-Oct) and every 2-3 weeks at half strength while the plant tends toward being quiescent. Other than that, I don't know how else I could help you. I would like to see a picture though. Perhaps I can help with what direction to take the pruning to make the tree most attractive.

Al