Euonymus is a genus of flowering and fruiting broadleaved evergreen and deciduous shrubs, vines and ground covers. They are prized and planted as decorative and low-maintenance ornamental plants used in borders, as foundation plantings and understory plants and as informal hedging. There are a great number of euonymus shrub species and cultivars, including the widely planted E. japonica, E. fortunei, E. kiautschovicus, E. alatus and E. europaeus, according to Clemson University. Pruning is readily tolerated to keep the shrubs in bounds of the planting site but is not required for healthy growth, flowering and fruiting.
Prune your euonymus shrubs in the late winter or early spring in order to preserve the maximum amount of flowering, fruiting and fall colour during other seasons of the year. Light grooming can also be done during the growing season, but do not ever trim the shrubs past the late summer, as this will spur a flush of tender growth that can be killed off by cold winter temperatures.
Remove dead, diseased, broken, discoloured or otherwise compromised branches and foliage. Sever the problem branches and stems down to the parent branch or to 1/4 inch above a healthy leaf node or bud. Pull all the cuttings cleanly from the shrub and soil and compost or discard them.
Reduce the height and circumference of the shrubs lightly if desired to control the size or to introduce a desired shape. Shear off the terminal tips, up to a second set of leaves from the branch tip, with this technique. Shearing will encourage branching at the tips and a flush of new foliage, thus giving the shrub a dense green surface appearance.
Rejuvenate overgrown or bare-centred shrubs by pruning away up to one-third of the longest and oldest branches each year for a period of three years. Distribute the cuts evenly throughout the shrub so that the overall natural form is preserved but there is greater air space around the branches.