Fasciation is a condition that produces flattened, often elongated stems (that look like several stems fused together, as with the Dusty Miller shown) or the cresting of flower heads (shown below on Gerbera). It can be caused by bud or tip damage (from animals, insects, slugs or hard frosts), viral infection, chemical damage (including herbicides), mechanical damage and bacterial infection (Rhodococcus fascians). Fasciation is commonly found on Forsythia, Foxglove (Digitalis), dandelions, Prunus subhirtella and Delphinium. Examples of cultivated plants with fasciated growth habits include Euphorbia lactea ‘Cristata’ (shown above), Salix udensis ‘Sekka’ (Japanese Fantail Willow), Cockscomb Celosia (Celosia argentea var. cristata), crested ferns and Cryptomeria japonica ‘Cristata’. The only control is to prune out affected portions (6″ into healthy tissue) and disinfect your pruning tools in case the root cause is viral or bacterial in nature.