Is there any difference in the care of a reg. hibiscus and a tropical hibiscus? How much sunlight should it have?
There is a difference in care requirements for hardy or tropical Hibiscus.
Wintering over is the biggest difference.
Here are some articles that will help with plant information and care requirements.
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/how-to-care-for-hibiscus-plants.htm
https://www.gardeningknowhow.com/ornamental/shrubs/rose-of-sharon/rose-of-sharon-bush.htm
https://www.extension.iastate.edu/newsrel/2002/aug02/aug0242.html
What makes the leaves turn yellow?
There can be a few reasons for yellowing leaves on your Hibiscus, and the article below will help you pinpoint and correct the issue.
My hibiscus is tall. I want to make it more into a bush. Do I cut it back first and then split it?
I would recommend starting out by cutting your branches back by about 1/3. You can also encourage bushier growth by pinching or tip pruning branch tips throughout the growing season.
For more information on pruning hibiscus, please visit the following links:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/tips-for-pruning-hibiscus-plants-when-to-prune-hibiscus.htm
We had some cool and windy weather and after that it looks like it has some disease attack it. Some leaves have turned yellow with black spots, but most leaves are a healthy dark green but no flowers.
I suspect your hibiscus has a fungal infection which can be treated with a fungicide. For verification, here is what a fungal infection on a hibiscus looks like:
http://www.hiddenvalleynaturearts.com/images/blackspots1.jpg
http://www.hiddenvalleyhibiscus.com/images/blackspotssm.jpg
Have you fertilized your hibiscus? That may encourage it to bloom as a growing hibiscus needs lots of nutrients in order to bloom well. . For more information on fertilizing hibiscus, please visit the following link:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/hibiscus-fertilizing.htm
Additionally, hibiscus will be more inclined to bloom if their care plan is being followed. I recommend a double-check on the care of your hibiscus using the following article:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/how-to-care-for-hibiscus-plants.htm
What is wrong with hibiscus plants that have black spots on the leaves? I saw a group of plants at a nursery and all looked ok but had black spots on the leaves. Did not know if I should buy one or if it would infect my other garden plants. Please advise.
I can't say for sure what the plants may have or the reasons, but I would not advise purchasing anything but a healthy plant specimen.
Here are some articles that will help you.
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/answers-to-what-causes-hibiscus-leaves-turning-yellow.htm
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/how-to-care-for-hibiscus-plants.htm
My plants have beautiful purple foliage and are 3 feet tall but no blooms. Seems I remember them blooming by this time last year.
Hibiscus plants need very warm temperatures in order to bloom, so if it hasn't been warm in your zone until lately, that could be the simple reason you're not seeing blooms yet. They also need lots of light, high humidity and fertilizer. Check to make sure you don't actually have buds that are falling off before they have a chance to bloom. These articles may help you:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/how-to-care-for-hibiscus-plants.htm
I have some large Hibiscus plants. They are growing beautifully but no blooms. Maybe two or one at a time and then a long period of no blooms. I live in central Mississippi. I have noticed that my blooms are fewer in the last few years.
Hibiscus need the right amounts of sun, water and fertilize in order to promote flower buds. I recommend that you review the following article and see if you are deficient in any of those three areas:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/how-to-care-for-hibiscus-plants.htm
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/hibiscus-fertilizing.htm