Culture Notes
Weigela grows best in a sunny location and moist soil. Shaded plants are straggly. Weigela also dislikes crowding. The growth rate is moderate and the shrub transplants well, reaching a mature height of 6 to 9 feet and a spread of 9 to 12 feet. Some annual dieback and winter injury make annual pruning necessary. It is best to perform any needed pruning immediately after they have flowered. The flowers are white, pink or red, depending on the cultivar. Canadian cultivars (the so called Dance cultivars) are the most cold hardy. Plants suffer in the deep south eastern part of the US. This plant is considered mostly allergy free and causes little or no allergy problems in most people.
Planting and establishing shrubs
The most common cause of young plant failure is planting too deep. Plant the root ball no deeper than it was in the nursery. In most instances, the root flare zone (point where the top-most root in the root ball originates from the trunk) should be located just above the landscape soil surface. Sometimes plants come from the nursery with soil over the root flare. If there is soil over this area, scrape it off. The planting hole should be at least twice the width of the root ball, preferably wider. In all but exceptional circumstances where the soil is very poor, there is no need to incorporate anything into the backfill soil except the loosened soil that came out of the planting hole. Never place ANY soil over the root ball. If a row or grouping of plants is to be installed, excavating or loosening the soil in the entire bed and incorporating organic matter enhances root growth and establishment rate.
Weed suppression during establishment is essential. Apply a 3-inch thick layer of mulch around the plant to help control weed growth. Keep it at least 10 inches from the trunk. If you apply it over the root ball, apply only a one or two inch layer.  This allows rainwater and air to easily enter the root ball and keeps the trunk dry. Placing mulch against the trunk or applying too thick a layer above the root ball can kill the plant by oxygen starvation, death of bark, stem and root diseases, prevention of hardening off for winter, vole and other rodent damage to the trunk, keeping soil too wet, or repelling water. Regular irrigation through the first growing season after planting encourages rapid root growth, which is essential for quick plant establishment.Â
Pests, Diseases and Damaging Agents
Pests: Four-lined plant bug makes brown spots on the leaves. Japanese beetle feeds on weigela.
Diseases: Bacterial crown gall causes formation of round, warty-looking growths on the lower stems. Leaf spots sometimes attack weigela.