Dahlias have a long season of flowering starting in the summer and continuing all the way to beginning of winter. They like sun but you can grow them in mid-shade, but for better flowering keep them in the sun.
You can plant Dahlias in borders or among shrubs and to give colors in different parts of the garden. Dahlia is also great for cuttings. There are a large varieties of Dahlias. They are divided in many groups such as the decorative Dahlias which have double flowers and come in giant-flowers, large-flowers, medium and small-flowered.
Another group is the cactus dahlia which have more spiky flowers. Cactus Dahlias also come in all sizes. The Semi-cactus also has similar varieties and then there is the ball dahlias they usually are either large or small sized. Collerete Dahlias have single flowers. And there is the Peony Dahlias. Dahlias like moist soil and they grow well in the wet season.
Adding humus is specially useful in sandy and dry soils. Make sure to give them enough spacing for growth 18″ to 24″ depending on the size.