I recommend that you follow these simple steps to guarantee longer lasting roses.
• Strip off the leaves below the vase water line.
• While holding the stem under water, diagonally cut (45 degree angle) 10mm off the bottom of each stem using a sharp knife.
• If roses have begun to dry out, place them up to their necks in water,
• Leave in a cool place and allow them to drink for 2-3 hours.
• Prepare a clean container and fill it with water, mixing with a sachet of rose conditioner supplied.
• Arrange in a deep vase allowing for plenty of stem in the water.
• Make sure the roses have an ample water supply daily by keeping the vase filled
• Place the roses in a cool place overnight.
• Never place your roses in conditions of high temperature, draughts or direct sunlight.

When growing succulents (Jade Trees, Rubber Trees, Cactus, etc.), treat them as though they need no water. Too much water causes the leaves to fall off. Too much sunlight burns the leaves and turns them yellow.
It is best to water them once a month with plenty of water like would be gotten from a downpour. They like dim to moderate light conditions and extremely little water.
These are the easiest plants to care for. Just don't over water or give them direct light.

I found useful and straightforward information about rose plants here: http://www.aero-garden.us/rose-plants. There also been explained about Rose Plants' Diseases, Symptoms, and the treatments....

i once heard that a good way to keep flowers fresh longer is to put a penny in the vase with the water. i thought it was a joke, but i tried it once, and my flowers looked gorgeous for about two weeks, and they lasted nearly a month. i also learned to put in an aspirin, too. apparently, the copper penny acts as a fungicide and the aspirin provides acidic properties to water.