Another favourite plant of mine is the Argyranthemum (Yellow Daisy) , a type of Margarite daisy. Usually available in garden centres in April -July. Not a Hardy plant, but nice for Summer Containers or borders. They grow to around 18inches and the more you take off the dead flowers, the more new ones appear. A regular feed with a soluble plant fertilizer keeps the flowers coming all summer, till Oct.
It is possible to take cuttings from none flowering stems, just below a leaf joint. They loof great planted with other flowers in "Blues" or "Pinks".