What's wrong w/ my hibiscus plant?

I have a pretty large hibiscus plant that has always done wonderfully, however lately it is looking kind of thin and has a lot of yellow leaves on it, what should I do? I've never had one of these plants (or hardly any plants) before so I don't know anything about pruning it or anything. Help would be greatly appreciated!!
What's wrong w/ my hibiscus plant?
This is a potted Hibiscus? They are heavy feeders, and they should be pruned. use a 15-30-15 fertilizer, cut back half of the tallest branches to just above the lowest leaf. They like lots of sun. Old leaves turn yellow and drop, if the new growth looks good, don't be too concerned. a good feed and pruning will encourage new branching and growth from a lower level.
Reply:you're probably not watering it enough but plants get yellow if you water them too much.
Reply:It does sound over watered for two reasons.

1. Yellow leaves usually mean too much water

2. Thin and spindly means that it does not have enough nutrition.

That would happen if you were washing out all the nutrition in the soil by over watering!

The last possibility is that you are overfeeding it.

That will burn off the roots as too much plant food builds up too much salt in the pot.

The roots cannot take up either food or water if they are burned, so yellow leaves and a weak plant will be the result.

If you feed every time you water, and you water more than once a week. STOP!

Once a week or when the earth is crumbly, and no food for a month of watering. Good luck!
Reply:If it is hardy it needs to be prined and watered, and fetilize it heavey.

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