My hibiscus tree keeps losing leaves. What am I doing wrong?
This article will help with the leaves falling off your hibiscus: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/answers-to-what-causes-hibiscus-leaves-turning-yellow.htm
My in-laws have had a Hibiscus plant growing outside of their garage for many years. We are selling the house and we want to move the Hibiscus plant to a new home. When is the best time of year to move it and how should I move it? Dig it out with a ball of soil attached or just uproot it and move it? I live in western Pennsylvania with cold winters and mild springs and fall.
The proper time to transplant the hibiscus is anywhere in late fall or early spring, depending on how cold your climate is and the variety you're growing. Hibiscus enjoy warm, sunny conditions, especially the tropical variety (which should remain in these conditions). However, hardier varieties can withstand cooler temps. This article will help with transplanting to avoid shock: https://www.gardeningknowhow.com/plant-problems/environmental/learn-how-to-avoid-and-repair-transplant-shock-in-plants.htm
In three years my hibscus has become 'Better Homes & Garden' worthy. Although it is starting to outgrow the area. Is it possible to divide?
Hardy hibiscus can be divided and is usually done so in spring. It can be divided by cutting the plant in half. Stick a shovel in the middle of the plant between the stalks and cut straight down into the root ball. Then dig out from around the plant (about a foot around). Pop them up out of the ground and then replant. Here is an article you may find helpful: https://www.gardeningknowhow.com/garden-how-to/propagation/propgen/dividing-plants.htm
Your plant may simply need a good pruning rather than division. This article will help with that: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/tips-for-pruning-hibiscus-plants-when-to-prune-hibiscus.htm
How do I plant a hibiscus outside in the ground and care for it?
If you have a tropical hibiscus, you can not plant it in the ground where you live. The will not tolerate the winter where you are. It will need to come in during the winter. This article will help you with that:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/wintering-hibiscus-indoors-winter-care-for-hibiscus.htm
If it is a hardy hibiscus, this article will help you with that:
https://www.gardeningknowhow.com/ornamental/shrubs/rose-of-sharon/rose-of-sharon-bush.htm
What is causing some of the leaves on my Hibiscus tree to turn yellow and fall off? Also, the blooms on my hibiscus only open for one day, then the bloom closes and two days later falls off. Is this normal?
This article will help you with the yellow leaves:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/answers-to-what-causes-hibiscus-leaves-turning-yellow.htm
Yes, hibiscus flowers only last for one day before fading.
I need a list of appropriate insecticidal sprays that will control the insects attacting my plants. The plants' buds drop of before they bloom with larva filled inside the the bud.
For most insect problems, I have found neem oil to be quite effective. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
Several years ago I bought four large, hardy Hibiscus plants. For a couple of years they thrived and were absolutely beautiful. Last summer it rained nonstop (no one had gardens) and the Hibiscus plants had a fungus look to them, and this year none of them came back. Is that common for Hibiscus plants? Can I plant more in the same spots, and should they do well again in better weather?
Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/how-to-care-for-hibiscus-plants.htm