Yet, it has the potential to become a widespread problem should it disperse elsewhere in California since it is known to infect more than 400 taxa of broad-leaved trees, shrubs, and conifers worldwide. European mistletoe does not appear to infect oak, eucalyptus, or conifer species within its current California distribution. Only seeds that are deposited on or very near a suitable entry point can survive to infect a host. It then flattens to form a disk-like, adhesive structure or holdfast. A wedge-like organ, primary haustorium, develops from the holdfast and penetrates the twig to just above the cambium layer.
Cortical strands grow from the primary haustorium parallel to and just above the cambium layer.
Cortical strands and sinkers continue to grow and comprise the water and food absorbing endophytic system. A swelling on the twig at the point of infection is often visible. The first mistletoe shoots grow only a few millimeters from buds on the holdfast. For American mistletoes , first shoots may appear during the first year. First shoots of dwarf mistletoes typically appear during years 2-5.