Broadleaf Mistletoe is fairly easy to start on apple trees. Rub the berries on a branch (not an old one that has thick bark), where it will get sun. It takes up to five years to get a plant that will bear the berries. Both male and female plants (bear the berries) are needed. Protect from birds and woodlice.
Grows in temperate climates.

Old apple orchards in UK are a primary source in Europe. In the U. S., a variety of trees may become infected. It becomes dangerous to the plant if infection becomes heavy, since it is a parasite, taking food and water from the plant.

Ideas on its growth, etc., with lists of susceptible and resistant trees here: Mistletoe