Grafting with Opuntia
Some cacti naturally grow slowly from seeds. Some cacti do not produce offsets, making propagation difficult. Some cacti are subject to disease when grown on their own roots. Some cactus mutants are unable to photosynthesize because they don’t have chlorophyll. Some cacti are naturally very small. Some cacti don’t bloom well on their own. All of these problems can be solved with grafting. Grafting plants is a widespread practice in agriculture (e.g., grapes or fruit trees). Grafting cacti is particularly easy.
Grafting involves the fusion of two components. Essentially all cacti can be grafted (fused together). They are compatible with one another. A shoot (scion) is fused with a rootstock (base of the graft). Thus, the top part of the grafted plant is different from the bottom part. The rootstock is usually chosen to be a plant that grows well on its own roots and that photosynthesizes well. The scion may be any cactus, but is usually a cactus that benefits from a strong rootstock.
Although many types of cacti are used as rootstock, the most common is Opuntia. Several different Opuntia species are used including O. humifusa because it is a strong grower that is cold-tolerant and resists most diseases. Another rootstock is O. fragilis.
Tubercles Grafted Onto Opuntia Rootstock
(embedded from YouTube)
Grafting Cacti onto Small Opuntias
(embedded from YouTube)