I have a Boston Ivy along my fence. It has done well for many years and spread to all my neighbors. But along my fence the original location, has not produced many leaves or just a few so far. What is the solution?
Boston ivy (Parthenocissus tricuspidata) is a fantastic design element and can be wonderful growing on a fence.
There are several possible pest culprits to your leaf drop or failure of leaves to emerge – spider mites, vine weevils, leafhoppers, scale and others, see the link below for more information.
https://portal.ct.gov/CAES/Plant-Pest-Handbook/pphB/Boston-Ivy-Parthenocissus
To add to this list, consider spider mites, which are tiny, red or white insects which suck on the plant juices, cause the leaves of Boston ivy to become spotted, covered with thin white webs, and discolored. While the spider mites themselves do not cause enough damage to kill a mature Boston ivy plant, they can weaken it significantly, causing the leaves to drop and making the plant vulnerable to diseases and other insect pests. It may be difficult to treat the mites as your plant is covering a large area. However, giving it a direct spray of water from the hose may help keep the population down. If you can access the area easily, try an insecticidal soap and spray thoroughly all over new growth, trying to get underside of leaves – any local nursery should have a supply handy. Leave the spray on for 10 mins and then flush the whole plant again with clear water. The higher humidity environments you are creating with these sprays are not conditions spider mites like so should discourage them from multiplying further.
Getting back to basics, the healthier your plant, the stronger it is and it can fight off pests and disease more easily. So, I would suggest you feed and water the plants you have to give them the best chance at survival. Top dressing with sheep manure, worm castings or a good quality well rotted compost would be a start. If this is not possible, then the application of a complete fertilizer (20-20-20) every couple of weeks along with the watering should give the plants a boost (follow the mixing directions on the package carefully). Mulching the area to help retain soil moisture and diminish weed competition would also be great.