Based on information obtained from the Dahlia Society of Victoria and Deb Collett's guide to showing, there are 15 common types of Dahlia that are recognised in Australia.
In summary these are the main criteria's that help distinguish the types.
Pompon
- Flowers should look like a golf ball on a stick
- All florets should be fully involute for their length ( curved to form a tube)
- The tips should appear to be round
- Looks like honeycomb
- Spherical
- Under 50mm diameter
Glenbank Honeycomb is a good example
Ball
- Florets are involute for the majority of their length, forming long tubes
- The bloom should be spherical
- Bloom size may be Miniature (under 120mm) or Small (120mm to under 160mm).
Isabel is a good example
Semi-Decorative (Ball)
- All florets should be fully involute for a third to half their length
- Tips should preferably be pointed
- Depth of the bloom to be a minimum of two thirds of the diameter but not exceeding it
Formby Crest is a good Example
Formal Decorative
- The centre should be closed and as high as the surrounding florets
- The florets should be broad and smooth
- Neither particularly involute or revolute and recurve gently to the stem
- Depth is two thirds of the diameter
Glenmarc Margaret is a good example
Informal Decorative
- The centre should be closed but is now cone shaped
- The florets should be broad and slightly wavy or twisted
- The Tips may start to revolute (curl backwards) but no more than one quarter
- Depth is two thirds of the diameter
Café Au Lait is a good example
Semi-Cactus (Decorative)
- The Centre should be closed but cone shape
- The tips are revolute for a minimum of one quarter to half their length
- Depth is two thirds of the diameter
Trooper Dan is a good example
Cactus
- The centre should be closed but cone shaped
- The Tips are revolute for a minimum of half their length, but preferably at least two thirds
- The florets may be straight or gently incurving but give the impression of pointy spines
- Depth is two thirds of the diameter
Pure Bliss is a good example
Exhibition Cactus
- The Centre should be closed but cone shaped
- The florets are very narrow and pointed with revolute edges overlapping for nearly their entire length
- The floret ends are strongly incurved and they regularly curve one way
- Depth should be at least half but not more than two thirds of the diameter
Winkie Paddlewheel is a good example
Fimbriated Cactus
- The bloom should meet the standards for either a Cactus or Semi-Cactus dahlia
- However the tips of the florets need to be fimbriated (split)
- They should be split into 2 or more points which should splay strongly
Winkie Volcano is a good example
Waterlily
- The bloom should be fully double, but the side view should look like a saucer
- Therefore the back tends to be flat
- The florets are broad and slightly cupped at the ends with rounded tips
Pam Howden is a good example
Stellar
- The mature florets are narrow and involute
- Preferably a contrasting colour or shade on the reverse
- Depth to be between half and two thirds of the diameter
Alloway Candy is a good example
Anemone
- Considered fully double but the centre florets are quite different
- Sideview gives a dome shape
- Generally but not always, one row of broad florets with rounded tips
Granite Queen Bee is a good example
Single
- A single row of exactly 8 florets
- Rounded at the tips and evenly distributed around the open centre
- Pollen should be fresh
Merton's Peach is a good example
Collarette (Collerette)
- A single row of exactly 8 florets
- With an added inner row of wavy florets with multpile divisions
- Pollen must be fresh
- Bloom size must be under 160mm.
Hillara Ice is a good example
Orchid
- A single row of exactly 8 florets
- Each floret must be fully involute for at least half their length
- Pollen should be fresh
- Bloom size must be under 160mm
Winkie Cupid is a good example