Always one of gardeners' favourite annuals, petunias now come in newer varieties offering even more spectacular shows of colour than ever before. The Wave Petunia and Supertunia are among those available at nurseries in the spring.

Wave petunia variety has become more and more popular since its introduction in the 1990s. It comes in three sizes: Tidal, the largest flower; Shock, the smaller flower; and Easy, a spreading plant.

Garden experts seem to agree that the Wave petunia was developed primarily as a ground cover. It may become overgrown in late summer and require pruning.

The Wave petunia is propagated with seeds and tends to grow a huge root system. The root ball may be a problem in baskets and planters.

The Supertunia is the most recent development in petunias. It too comes in many colours and sizes, as well as in single and double blossoms.

The Supertunia variety adapts better to planting in pots than the Wave because it drapes easily over the sides and grows very large without developing the massive root system of the Wave.

The Supertunia is propagated with cuttings, thus preserving its quality and vigour.