Well I have a tropical hibiscus, same color and bloom as yours and I brought it inside during the winter. Before I brought it inside I noticed that some leaves had fallen off as our nights would get to 40 degrees, the tag on my hibiscus said bring inside once 50 degree nightime temps come so that could be a possible suspect.

However the biggest problem and what made my hibiscus look completely dead, I literally have about 5 leaves on the thing because of spider mites. I noticed MANY leaves going yellow and dropping and the bushy plant started to look bare. I would check to see if you have any insect issues, although this is more common indoors that would definitely be my best guess.

Good job on all the blooms--- plant looks beautiful!

Hmm you might be on to something there. I thought I was invincible to pests (novice mistake) but upon closer inspection there are some gnat like bugs flying around and some spider webs on my hibiscus and my desert rose (which has only a few leaves left).

After googling, it looks like there are a million home remedies to get rid of spider mites. Is there anything that you found particularly effective? Based on what I have at home currently, I decided to go with the alcohol/water bath.

Aircad,
I noticed your first post, but didn't have the time to respond. Some of the leafs show a very obvious sign of bugs.
Step 1,
Identify the pest. Spider mites will have small webs near new growth and close to the stem and leaf. It it un-mistakable. They also create a bumpy 'malformation' effect to leafs. Best bet is raise the humidity as these beasties hate water. It is winter here and all my tropicals are indoors. I shower them monthly and spray with water daily. Even with this, I am still battling small outbreaks. Make sure you spray under the leafs.
Even though the dry humidity inside ecourages the mites, moisture encourages gnats and white flies. By scraping a layer of soil from the top of the plant and replacing with new, you remove the eggs and larve they produce. Make sure you discard this quickly.
Step 2,
Watch for water control. Over watering/root congestion will have lower leaf loss and yellowing. Lack of water will be displayed as up leaf wilting or softness. Try to find a happy medium in the winter. After a recent root pruning, I noticed the lower soil was still moist, while the upper layers were�dry. This is a partial drainage issue, that I addressed.

Remember, tropical hibs are not designed for winter. We need to modify their habitat to accomidate. During winter, get a hand sprayer, and use it. Also cut back on the fertilizer. This is a great time to prepare your plant for next summer. I do a lot of pruning and preparation. My goal is survival and preparation for next year. I could care less about winter blooms.

Hope this helps,
Ed

Ed,

Thank you for the great advice. I've gone and moved the plants that are affected by pests indoors into the guest bathroom. I removed the top layer of soil as suggested and threw it in the trash shoot. Now I've got my humidifier I used back north on full blast in the bathroom. The reading now says it's 80% humidity in there. I'll be sure to spray the bottom of the leaves if the humidifier doesn't seem to help with that. I don't think the flying bug problem is nearly as bad as the spider mite problem but if I notice a lot more of those critters flying, I'll alter my humidifier remedy.

I haven't added any fertilizer to my plants. Since I got the majority of them in November/December I didn't want to start fertilizing in the winter especially since I knew they would be going through some shock while adjusting to their new environment.

Thanks for all your help, I'll be sure to post again if I run into more problems.

I have a hibiscus tree that I planted in the summer. The leaves have since turned yellow because of winter in NJ. Is it possible the plant will come back in the spring with pruning? A friend of mine says there neighbor has hibiscus that "dies" every winter, than comes back with pruning. It's kept outside year round.

Bob968,
In your climate, only Hibiscus Syriacus (Rose of Sharon) and Hibiscus Moscheutos (Swamp Mallow) will survive your winter. Tropical Hibiscus will not. Hopefully you have one of the first two as the third may already be past rescuing.
Ed

Thanks Ed,

Guess I'll see what happens when the warm weather comes back. If it winds up being dead, it sure looked pretty for 5 months or so. I'll just make sure to do more research on the next one I get.