The flower buds on my hibiscus plants fall off before they open.
This is likely thrips. This article will help:
https://www.gardeningknowhow.com/plant-problems/pests/insects/controlling-thrips.htm
I have three twined-bark hibiscus plants. Two are doing excellant but one is losing leaves, turning yellow, and blooming about three times the rate of the other two. I would like to clean the few leaves of this sick plant but I'm not sure what home remedy to use like alcohol, dishwashing soap and water, etc. Can you help?
Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/answers-to-what-causes-hibiscus-leaves-turning-yellow.htm
I am looking at moving some hibiscus plants and was wondering if I can divide them to make more plants?
Unless they are "growing" by putting out suckers (stems from the ground), you generally cannot divide them, as the overall majority are best propagated through cuttings. This article will help you:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/hibiscus-propagation.htm
However, hardy hibiscus can sometimes be divided by cutting the plant in half and is usually done so in spring. 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.
I just bought some hibiscus plants and there is yellow powder on the buds. Is it a form of aphid? What should I do to prevent more infestation?
It may simply be pollen from other plants. This article will help you determine if it is aphids: https://www.gardeningknowhow.com/plant-problems/pests/homemade-aphid-control-a-natural-way-to-kill-aphids.htm
How would I do this with a Hibiscus Tree? Trim back the plant – Trimming back the plant allows the plant to focus on regrowing its roots. In perennials, trim back about a 1/3 of the plant. In annuals, if the plant is a bush type, trim back a 1/3 of the plant. If it is a plant with a main stem, cut off half of each leaf.
The same concept applies for trimming hibiscus--cutting by a third. These plants generally regrow and fill out rather quickly. This article may help you as well: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/tips-for-pruning-hibiscus-plants-when-to-prune-hibiscus.htm
I just bought my first two trees and already have problems with pests and yellow leaves. Help?
Treating the plants with neem oil should help with controlling the pest problem. It will also help in treating any fungal-related issues that may occur. Here is additional info on neem oil: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
As for the yellowing, this is probably stress related and most likely due to the pests. This article may also help: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/answers-to-what-causes-hibiscus-leaves-turning-yellow.htm
I planted a vintage hardy hibiscus last year. I bought it in Franklin, PA. at their apple festival. This word below the picture of the hibiscus was on the tag: 'BORDEAUX'. No info was on the tag as for annual or perennial or take it inside for winter, etc. I planted it in a big planter I built in my backyard out of big block. It is up three cinder blocks high. We had the worst winter for a while; I am in Pittsburgh, PA. Please tell me it's going to live. I broke off the long stems and they were very dry and broke quick. Is there any hope it will survive? I don't know if I should cut with a saw down lower to see if it's dry at the base, and I didn't know if there were hardy varieties for my area or not.
This article will help you determine if it is dead:
https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm
If the stems are alive, it will recover.