Next, I have a 7 to 8 foot hibiscus tree that is about 4 years old. It gets sunlight all day. The buds are so plentiful that the branches droop to the breaking point, yet it has never blossomed. I tried Miracle Gro this season (as I did with the trumpet vine) and got 3 blooms out of about 300 buds. Help!

As far as the hibiscus tree goes, I’m not sure if you are referring to an indoor hibiscus tree or a rose of Sharon, which is an outdoor tree with Hibiscus syriacus as it’s Latin name. I am going to assume that you are referring to the rose of Sharon, since the trumpet vine you mentioned is also an outdoor plant. Since the tree receives full sun, let’s concentrate on its fertilization. The two main things to do are fertilize with a high phosphate fertilizer and reduce the amount of high nitrogen fertilizer, as mentioned above with the trumpet vine.