Theoretically, borage plants can be propagated by rooting cuttings trimmed off the plants, but the seeds germinate so readily that the most common method of propagating borage is to collect the seeds from the dried flower heads in the fall, saving them for sowing the following spring.

Plant the seeds 1/4 to 1/2 inch deep in early spring after the final frost has passed. Thin them when they are 6 to 8 inches tall to a spacing of 18 to 24 inches apart. Borage can bloom from late spring through summer and will reach maturity in about eight weeks, at which point you can harvest the leaves and flowers as need.

Borage seed propagation is very easy. If you want to collect seeds to give away or plant elsewhere in the garden, pick them off the plant when the flowers begin to wither and brown. The seeds can be stored for at least three years. Growing borage from seeds is just as easy. The seeds can be sown outdoors four weeks before the last frost.