Weigelas respond to both renwal and headking back pruning. By now you can start with renewal pruning. This is on an annual basis. You remove a portion of the oldest (and also then the tallest) branches down in the crown, perhaps a forth or third of them. After 3 to 4 years you have completely removed the taller branches. For those not removed, use what is called an heading back cut. You can prune done to another bud or small branch leaving a natural growing point. do this randomly, leaving a more natural appearance to the shrub. You can do this after the plants are dormant this fall or before growth begins next spring.