AA, Giant or Dinner Plate Dahlia
These are the show-stopper dahlia flowers, the ones that measure ten inches or more across, and hence the common use of the name dinner plate dahlia. A good example is Bodacious, an informal decorative variety with yellow tips on its hot-red florets. (Dahlia flowers are composites, and the blooms are made up of florets, rather than petals.) Bodacious always wows visitors to the farm, and each flower is a bouquet in itself. Before 1975, the American Dahlia Society grouped all dahlias over 8 inches across as A size, but so many gigantic hybrids were introduced that the new AA designation was introduced.
Giant dahlias provide brilliant displays in the garden, wow judges and audiences at shows, and make dramatic statements in floral decorations. They require staking in the border or row as the huge blossoms are otherwise susceptible to rain and wind. Dahlia flower types included in this size category are formal and informal decorative, cactus, semi-cactus, incurved cactus and laciniated.
The largest of these dahlia flowers also come close to ranking as dinner-plate size. A-size dahlias have blooms that measure 8-10 inches, or 20-25 centimeters. They include the formal and informal decoratives, cactus types and laciniated versions of those dahlias. A lovely example is Snowbound, a white formal decorative dahlia with beautiful form and stustance. Snowbound is elegant in wedding arrangements and is a consistent success in exhibitions.
Dahlias in the A group, like those in the AA group, are inclined to need staking to ensure that they withstand summer storms, but any extra effort involved to grow these dahlias reaps great rewards.
B Size, or Medium/Large
Some growers group B size dahlias with their large dahlias, which makes sense: B dahlias range in size from 6 to 8 inches, or 15-20 centimeters. As with the A category, B size once included all dahlias from 4 to 8 inches, but the category was divided into B and BB with the introduction of many new dahlias from the mid-20th century onward. Part of the rush of newcomers involved a host of new cactus and laciniated dahlias, the latter with split florets. The B class has the largest number of laciniated dahlias, with more than 100 of this popular variety listed in the class.
A favorite among Lynch Creek dahlias is the elegant Marlene Joy, a creamy white laciniated dahlia whose slender rolled florets are slightly forked and tipped with brushstrokes of rich color ranging from wine to pink to lavender. It grows to 4 1/2 feet tall and has good form and substance.
BB Size, Medium/Small Dahlia
As with the other dahlia size groups, BB dahlias include formal and informal decorative, cactus type and laciniated dahlias measuring 4 to 6 inches or 10-15 centimeters across. This is the largest of the dahlia size groups; the American Dahlia Society in 2008 listed 2118 dahlias registered in the BB category.
One of the Lynch Creek Farm favorites is Just Peachy, a luscious blend of yellow, peach and orange in semi-cactus form. It lasts well as a cut flower and has strong stems, which suit it well for decorating. Introduced in 1986, it has been a consistent show winner ever since. BB-size dahlias are large enough to make a strong visual impact but small enough that they lend themselves well to flower arranging.