There are probably more than 60 different forms of Euonymus, but only a few of these have become popular as landscape plants. This single genus of plants represents vine, ground covers, shrubs and small trees. Although the tree types are not common for landscape use, one of them, the Wahoo, “Euonymus atropurpurea,” is often found as a small native tree in wooded areas. While the trees are not particularly noticeable in summer, in fall they have attractive color and clusters of deep pink to orange berries which become evident after the leaves have fallen.
A shrubby euonymus that is very popular for landscape use is the winged euonymus, or burning bush. The compact form is most useful and produces dense growth not only making it a good specimen, but also suitable for unclipped hedges or screens. This excellent plant has brilliant pink to red fall color, is cold hardy and is essentially pest free. The desire for evergreen plants in the landscape is what has made evergreen varieties and species of euonymus popular. Euonymus have been found to be one of our hardiest broad-leaved evergreens, although during severe winters in some climates the plants turn brown or may be partially killed back. When this happens, only the deadwood needs to be cut out, and the plants need to be pruned enough to reshape the plants. Because they leaf out fairly early in the spring, do not prune out any winter-killed wood until new growth appears so that live wood can easily be seen.
Among the evergreen euonymus is a creeping type often used as a ground cover, known as the purple-leaf winter creeper. There is also a climbing type commonly known as evergreen bittersweet. The most used, however, are the shrubby types. Some of the best adapted varieties included Manhattan, Pauli, Sarcoxie and Jewel, although many other varieties have been introduced and may be available in some localities. An objection to the evergreen euonymus is that its leaves may turn brown during the winter but not drop off. While this often happens, especially when plants are in exposed locations, the leaves are normally green until Christmas but drop and are covered by fresh green growth in late March.
The amount of browning is usually relative to the severity of the winter. In mild winters, this may not occur at all. The evergreen euonymus may be attacked by several plant problems. One is euonymus scale, and the other a disease called crown gall. Euonymus scale is an insect pest which may be found on the twigs and undersides of the leaves. The scales are small, grey to white and can be very destructive. The upper sides of the leaves often become yellowish as the sales on the undersides damage them.
Heavily infested branches should be cut out and burned. An approved insecticide spray should be applied in late spring and repeated several times during the summer. Be sure to cover the twigs and undersides of the leaves quite well. Crown gall causes swelling of the twigs, usually near the base of the plant. When these galls are seen, plants should be removed and destroyed. Euonymus should not be planted back into the same area.