Shamrocks are so easy to grow. My PX: When they start looking a little droopy give them a large dose of water. I keep them in the AM light and worship their eye-catching little white flowers.
They make me out-and-out perky every morning when I am making my breakfast and see their 3-pronged heads peaking out my window. They love the sun and so do I. I guess that is why we are so well-matched. It also happens to be the only flower I can grow.
Shamrocks are bulbs, and like all bulbs they need a episode of dormancy every once in a while. They will need a few rest periods every year to remain providing their best growth.
When your shamrock plant starts looking a little dreadful, stop watering it and set the pot somewhere that it will remain cool and dry for about two or three months, except the purple varieties which only need about a month of rest.
After they have their 'vacation' you can continue watering and give them a shot of all purpose house plant food (10-10-10), and in a very short time you will see new growth.
At the end of the sleeping cycle you might want to remove the Shamrock bulbs from the pot, separate them and replant just under the surface of the soil in good, slightly sandy houseplant soil.