Dahlias are tuberous perennials that are Mexico's national flower. They were cultivated in other countries in the 1800's. They're are named after the Swedish botanist, Anders Dahl, who studied the seeds and tubers from this flower in 1789. The genus dahlia is in the class Agnoliophyta and the family Asteraceae. Some of the many different species include the cactus, semi-cactus, orchid, ball, water lily, stellar, formal decorative and informal decorative.
Informal decorative dahlias often have feathery-tipped petals or petals that are long with slightly rippling edges. Formal decorative dahlias usually have shorter petals that are quite large. Stellar dahlias are often ball-shaped with flat, open petals that are folded down to pointed tips. Some have two colors, which can be very dramatic and elegant in appearance.
Water lily dahlias do look like water lilies. They have slightly cup-shaped petals with rounded tips that radiate upwards like water lilies. They can be seen in blended, softer shades of yellows or pinks as well as in brighter orange and yellow blends.
Ball dahlias look very much like a ball on a stem. The short, round petals are cropped and dense to give a completely round look to the flower. Orchid dahlias usually have a striking shape. The eight petals around the flower's center are often rolled, sometimes giving the flower a starfish look. The Lupin Sheila orchid dahlia has dark pink outer petals that are rolled and reveal white inner petals around a yellow center, giving it the look of a colorful pinwheel toy.
Semi-cactus dahlias can have extremely pointed tips on petals that radiate from a ball-shaped flower head. Novelty double-centered semi-cactus dahlias have petals that turn upwards and this adds a unique hollowed-out look to the petals. They can often be seen in yellow and white.
Full cactus dahlias can be very exotic in appearance and have spiky-tipped rolled petals with hollow, straw-shaped ends. Some can look like a sea anemone. The Glenbank twinkle cactus dahlia is bi-colored in dramatic contrasting colors such as white with bright purple tips and yellow with ruby red tips.