1. Planting: To plant your new Crape Myrtle, start by digging a hole that is one and a half times wider than the plant's container. Then, place the plant in the hole, ensuring that the top of the root ball is level with the ground. Backfill the hole with soil, and water the plant thoroughly. After watering, apply mulch around the base to help retain moisture and reduce weeds. 

Keep in mind that new plantings need more frequent watering than established plants. Factors like wind, temperature, and soil type will affect your watering schedule. 

In early spring and again in early fall, feed your plants with an all-purpose fertilizer, following the instructions on the label. If you purchased a Crape Myrtle that comes with a stake, leave the stake secured to the trunk until fall or until the stems are strong and well-established.

2. Watering: Water your plants thoroughly but not too often to promote deep root growth.

3. Fertilizing: Fertilize once yearly (in the spring) with a slow-release fertilizer. Apply mulch around the base of the tree to retain moisture and protect the roots from extreme temperatures.

4. Pruning: Prune your Crape Myrtle in late winter or early spring, just before new growth. Start by removing dead or damaged branches and any that are crossing or rubbing against each other. Trim branches growing toward the center to improve air circulation and encourage healthy growth. 

Cut back the top to your desired height, leaving at least two or three buds on each branch. Avoid severe pruning or "topping," as this can harm the tree’s health and appearance.