Dianthus are perennials that can be planted in fall and will bloom fall, winter and spring.  They may stop blooming during the heat of our summers - but keep them watered and in some shade to survive the summer - and they will bloom again the following fall.  Give them some fertilizer once temperatures cool off and help them put on a cool weather display.  Dianthus come in reds, whites, pinks, and combinations of the three colors.  Most varieties stay fairly short so are best planted at the front of your flower beds.  They are one of my favorite cool weather plants.