The swollen area at the top of the shank from which new canes (basal breaks) emerge. In climates with extreme heat or cold, it is best to protect the bud union by planting it below the soil level and mulching over the top.

the swollen part of the stem where the scion of a grafted rose meets the under stock

The area where the bud eye was grafted on the root stock.

the point where the rootstock is grafted to the flowering variety. The bud union can be seen as an enlarged area at the base of the plant, whether purchased as bareroot or in a container. The bud union is also used as a gauge to mark planting depth.

The junction on a stem, usually swollen, where a graft bud has joined the stock following the process of budding. Usually found at or near soil level.

The point where a plant has been grafted. Usually indicated by a small knoblike growth on a tree, shrub, or rosebush.

place (often a slight swelling) on the plant stem where a bud or graft is joined with the rootstock.