Rose propagation using potatoes requires rose cuttings, 15-to-20cm (6- to 8-inch) pieces of rose stem. The rose cuttings root well in the potato base because the potato provides moisture and nutrients to the newly growing roots. The rose may even enter into a symbiotic relationship with the potato: information on vegetative propagation from the University of North Dakota in the US shows tomatoes grafted onto potatoes in which both plants thrive. Although a softwood rose cutting should not require it, you may dip the cutting in rooting hormone or a willow-wood infusion prior to inserting it into the potato.
Cut a piece of rose bush stem 6 to 8 inches long with a sharp, clean knife or pruning shears. This should be done in winter when the blooms have wilted and hips are forming. If collecting multiple cuttings, keep them in the shade until you are ready to begin the next step.
Cut off the spent blooms, hips and lower leaves. Do not cut the nodes, or eyes, above the leaves.
Fill the nursery pot 1/3 full with potting soil and place on a plate or drainage pan.
Punch a hole 7-8cm (3 inches) deep into a healthy potato using a screwdriver.
Insert the bottom end of the cutting into the potato hole.
Place inside the nursery pot and cover with soil so that about 7-8cm (3 inches) of the cutting sticks out.
Place in indirect sunlight and keep surrounding soil moist but well drained for two months. Transplant into a permanent place outdoors in the spring.