Creeping vine plants require plenty of sunlight

I believe the plant is one of the trumpet vines or trumpet creepers judging from the foliage.

Are you sure the leaves are stripped, or is the plant dropping its leaves? These plants will require at least eight hours of full sun each day. They like full sun. If they don’t get enough light, they will drop their leaves.

If they are watered too often, they will drop their leaves. Or if they are being watered the same, if one spot does not drain water as well as the other spots, you might have leaf drop.

Some plants will drop their leaves shortly after planting or if they are planted in locations that are radically different in light levels from the nursery. Check to see if these stems are still supple and bend easily and are not dead. If they are still supple and there is plenty of sunlight, you will probably see new leaves coming out.

You should be aware that as the plant gets older, it will lose its leaves on the older wood unless there is no growth coming from those older stems. On those older stems, you should expect them to be without foliage as they get older unless you prune the plant to maintain that foliage.

Leaves being stripped off the plants doesn’t make sense to me, but there are a lot of things that don’t make sense to me. I suppose it is possible an insect could be stripping the leaves off, but I would think you would see its presence. I don’t know of any night feeders that would be stripping them off.

As a precaution, flush the soil around the plants with lots of water, several times. Add a good fertilizer such as a Miracle-Gro, Peters or Scotts product. Get on a watering schedule for trees and shrubs and not for flowers. Let’s see what happens.