Grow plums and gages in a sunny position with fertile free-draining soil. The best time to plant your new tree is during its winter dormancy. Dig a wide planting hole and bury the root ball up to the juncture between root and stem, pressing the soil around the roots and adding a thick layer of mulch before watering well. Young plum and gage trees may need staking as they grow, so use a soft tie and make sure to allow a little bit of movement between the trunk and the stake. Water young trees every week for the first year. Give your trees a light prune in early summer to achieve the shape you want, always remembering to use clean, sharp tools to avoid silver leaf disease.