how and when do I propagate and or split gazania plants
Thank you for including a picture. What you have are blanket flowers, Gaillardia, not Gazania. They are lovely flowers and known to bloom all summer until frost. They are termed a "short-lived" perennial and 3 years is about all one can expect of them. Saving seed is easy: store seed over winter in a jar in the refrigerator. In spring, after danger of frost is past, sow the seed outdoors, cover lightly and keep the ground moist, not wet. Of course, start seed earlier indoors if you wish. In late spring (they don't come up early) check your plants and divide them once they have fully emerged. The plant self sows so you may not need to divide them.