Plants from warm climates - such as Paris daisies, osteospermums, fuchsias, geraniums (or rather, pelargoniums, to be pedantic) - often last from year to year in Irish gardens. But some become woody and awkward with age, and a sharp frost will make mincemeat of them overnight. Stem-tip cuttings (from the top two or three inches of a healthy, non-flowering shoot) can be taken any time during the growing season and over-wintered in a green house, ensuring that fresh plants are available for next year.
Because these tender plants originally came from dry regions, make sure that the compost into which you root the cuttings is free-draining and not sodden.