Aruba, there is a product called Cloud Cover that we spray our Japanese maples with each May to keep them from burning over the summer months. My sister learned the hard way the first year she planted them here that it was a treatment we just cannot overlook here with our 100+ summer temps. But when we learned about it at a local nursery, they also said it protects Japanese Maples, Jacarandas, etc., during the winter months to keep frosts from killing them. Hopefully your trees will come out of it eventually, and I would recommend you try that before the first frost next winter to see if it helps. It sure has helped here. It puts a coating on the leaves and branches, and my sister and I will never go without it again.
Also, would frost blankets/covers help? I got one at Lowe's a few years back to protect our bonsais, and it worked really well. And I think they come in different sizes.
