Protect from cold and wind. Or take softwood cuttings this summer and root in equal parts peat and perlite. You might try the method you used when you removed a piece from your neighbor's plant. Shrubby perennial hibiscus can be pruned almost to the base when dormant to encourage bushy growth and flowers. The person who sprayed it is no longer in business.
Aphids cause pecan leaves to curl and look chlorotic.
The insects discharge a honeydew as they drink the juice from the leaves. When this sticky substance lands on foliage, a sooty mold often develops. Pecan nut casebearer can cause nuts to fall prematurely. You'll likely see their larval droppings on the nuts. I would try to fight aphids by releasing ladybugs, a natural predator, and to battle the casebearer with trichogramma wasps or green lacewings.