This mix can be purchased from many garden centers or you can buy materials separately and mix them yourself. Slow release fertilizer in very small amounts should be added. Once the plants have rooted they will develop a better root system before removing from the mist bed. I root everything in a mist bed in small two or four inch pots. If you are not familiar with a mist bed, then you should look for a book or video on the subject.
Crotons root very easily in mist beds as do hibiscus and dozens of other plants.
Restricted watering doesn't help, but there is a solution. I have been using a material called hydretain that will cut your watering by fifty percent. The product has been used by golf courses for years and they will tell you it has saved them a lot of money. In areas where there are water restrictions and folks use hydretain on their lawns, water police believe they are not observing water restrictions because the grass is so green. This may sounds like a sales pitch but in reality it is one of the best products you can use to keep your lawn greener than any in your neighborhood.