Maybe it's time for a repotting? Also, you've not mentioned your fertilization routine and that is very important for healthy, flowering plants.

A tip about the watering: some potting mediums can become hydrophobic when they dry out. This may cause permanently dry pockets to form. In conditions like this, water will run out of the bottom quite rapidly, but much of the volume of the container will still be bone dry. It's a good idea to drench the heck out of your plants occasionally to insure that this does not happen.

hmm. maybe they do need to be re-potted. and probably fertilized some more. i usually use the spikes. i'll have to do some poking around and see whats goin on.

Dori's advice is always right on, but let me say something additional about fertilizing hibiscus.

If the plant is in a part of the growth cycle when it SHOULD be growing well and leaves are green & it's aborting or not setting buds, it's likely a light or fertilizer issue. The light issue is obvious - you need more of it if the plant is not in full sun. If you expect a fertilizer to help optimize bloom production on this plant, you NEED to insure it's low in phosphorous (the middle number) or you can look for a high % of bud loss or minimal budset. Do not use anything labeled bloom-booster or similar on hibiscus. There is also no need to pay the long dollar for anything labeled "hibiscus food/fertilizer". Miracle Gro all purpose soluble fertilizer in the 24-8-16 or 12-4-8 blend works wonderfully on these plants, and its performance can be enhanced by adding 1 tbsp of potash per gallon of soil at potting/repot time or including a K supplement like ProTeKt 0-0-3 in your fertilizer regimen. Ca and Mg are also very important to the plant, so you need to be sure they are included in the soil (dolomitic [garden] lime) when you purchase it, or add it yourself - the same applies when you make your own soils.

If you want to rejuvenate the plant, wait until after Memorial Day & treat it just like the pics you see in the thread I'll link to below. I do my brother's and our (business) accountants this way every spring & they couldn't bear to watch the first time I did it. I've also treated those I've wintered over in like fashion & they always do well.

Al

Here is a link that might be useful: More info

Sasha, I used to kill hibs (back in the 80's) left and right. One thing that saved them, at least I think it's the reason, is proper fertilizer. My hibs are only fed with true Hib fertilizer bought at www.plumeriapeople.com Ebay.com or if desperate, (prices are sky-high,) www.stokes.com
Hib foods are only inteneded to use on Hibs, they don't recommend for other plants. Since you're busy, have two jobs, please, purchase hibiscus food. Sprinkle and water. Hib ferts last 3 months, (I divide mine by 3 and fertilize monthly) but follow container directions, and it'll last 3 months.
Hibs love sun. An east window may not be enough light. Mine (9 varieties) are kept in south and east in winter, and outdoors in summer..They enjoy humidity, but not to the point they won't live without it.
Fresh, circulating air is important. My tree his is about 15 yrs old, blooms most of the year..
Mites love hibs, especially if soil is kept moist, and air dry/stuffy. So keep an eye out for webbs. Whitefly is another insect that will live comfy-cozy on leaves.
For smaller trees, misting and wkly showering perks them up..tall trees, (4' and over) should be hosed outside. Weather permitting. If you have a brighter window, relocate..in sprng till autumn, set outdoors. Starting in shady spot, working to direct sun. Good luck, Toni

What blend of fertilizer you supply hibiscus with will not be the deciding factor in whether they live or die. The plants will tolerate an extremely wide range of fertilizers. Plant decline and death would almost certainly be attributed to other inappropriate cultural conditions, though fertilizer blend could easily be the determining factor in whether they bloom or not. The "true hibiscus fertilizer" that Stokes and Plumeria People sells is a 10-4-12 blend, which is very close to a 3:1:3 ratio fertilizer. You might have noticed that I suggested the 24-8-16 or 12-4-8 MG blends, which are BOTH 3:1:2 ratio fertilizers. The difference being that the 3-1-3 ratio Stokes & Plumeria People sells is only slightly higher in K (potassium), which is why I suggested using the commonly found and VERY inexpensive MG products with a little extra potash or ProTeKt added (both K [potassium] sources) to increase the K levels to nearly exactly the same end ratio as the fertilizers listed as "hibiscus food". There is no need to pay high prices for ANYTHING labeled 'hibiscus food' or 'hibiscus fertilizer'.

Al

Hib fertilizer. 1 lb is 6.95. I don't consider 6.95 an astronomical price for a pound of fert.
Sunshine Gardens sells organic Hib food, 5lbs for 6.99. Shipping isn't included in these prices..that's the drawback. Some states sell hib fertiilzers at their local hardware store and/or nursery.
If you can find it locally, I'd look into it.
All I can say is, up until I started using Hib food, they died. Since using, tropical and hardy hibs do great.
BTW, I've never used organic hib food, so don't know if it works as well as chemical. Sunshine Gardens sells chemical Hibiscus fertilizers, but have since sold out. Toni