Question
One of 4 bought at Home Depot is not doing well. The leaves are drooping about as much as possible.  It's not lack of water.  Thanks

Answer
Johnny,
Since I don't know what part of the US you are in, and you don't say if the plants are outside or inside,  I'll just suggest some of the reasons this plant might drop leaves and you'll have to see if any of them apply.

1. If the temperatures are going below 40 degrees at night where you are, and the plants are outside, this could shock the plant into dropping leaves.

2. If you fertilized the plant when it was dry (added fertilizer to the water when you went to water it) this could cause the plant to drop leaves. Or if, when you are watering, you only give the plant a small amount of water, then the roots won't ever be well hydrated and roots will dry and die back, causing the dropping of foliage.

3. If the plant was not watered regularly when it was at the HD (and they are famous for not caring well for their plants) then it might be showing to results of that drying out even days after you brought it home.

4. If the plant is kept constantly wet - especially if the pot is sitting in a saucer/dish where the water is always standing around the pot - this causes the roots to rot and then the leaves yellow and fall off.  You want to be sure that you water it deeply, and let the water fill any dish below, but then after an hour or so empty the saucer so that the pot isn't standing in water any more. Then wait until the soil starts to dry again before watering well. A deep soaking less often is better than a little every day.  

5. If the plant was left in a very hot, or very cold, car in between the time you bought it and got it home, that could cause the dropping of leaves.

6. If the leaves got hit with something inadvertently - spray from cleaning the windows, powerwashing a deck, a neighbor spraying a lawn or other area with chemicals, hot water from a hose that has been in the sun, etc - could cause the leaves to fall.

OK - so even if you don't know what caused this, what do you do now?  You water the plant very well but don't let the pot sit in water. You wait until the soil dries, but before the plant wilts, to water well again.  You keep the plant in full sun. If the temps are going below 50 degrees at night where you live you bring the plant into the garage for the night. You wait to fertilize until the plant shows some re-growth of the leaves.  Once you see some new leaves coming out on the stems, water the plant well first, wait a couple of hours and then fertilize with the product of your choice used according to directions. Never fertilize a thirsty plant.

I hope this helps!
C.L.