Dahlia spp. & cvs.

Dahlia spp. & cvs.
ASTERACEAE

Herbaceous Tuberous Perennial

Zone: 8
Native habitat : Mexico (primarily)  but have been widely cultivates all over

Conditions 
Soil: fertile, humus rich
Moisture: well drained is essential, average
Light: full sun
Exposure: winter protection
Plant size (h x w): 12″-5’x 12″-3′
12″-24″ (bedding plants) or 3′-4′ (decorative)’ can be up to 7′
Other:

Aesthetic
Shape/stem:some have herbaceous stems, others have stems which lignify in the absence of secondary tissue to esprout following winter dormancy
Leaf:pinnately divided, usually serrate, green to black in colour, 
Flower: wide range of colours, sizes and styles; flower head is a composite (both central disc floret and surrounding ray florets); single to double blooms; flower heads can be flat to rounded
Bloom:  mid-summer to fall
Other:

Treatment (how to…)
Plant: general; be sure to water; stake at time of plant; ideal to lift yearly; be sure to plant in a well-draining site; plant in May to early June
Maintain:  high maintenance; lift for the fall or protect with mulch so they survive the winter; usually need string, place stake in the ground at planting time as to not spear tubers; deadhead to keep flowering sign; see handout given for all the proper pruning techniques as well as proper care through seasons

Propagate: basal shoot cutting, seed (indoor start), division of tubers (when shoots are 1″ tall separate into portions, ensure each section has both roots and shoots)

Uses
Landscape: bedding plant, cottage garden, cut flower, mixed boarder, boarder
Companion planting: pair based not the colour of flower and size; looks gorgeous with most anything 
Medicinal: none known; tubers were eaten in the past
Other:

Vulnerabilities
Pests and disease: prone to earwigs and mildew
Deer resistant: no
Other animals: 

Interest
Local info,: not native
Pot size (to purchase):
Nature: gorgeous flower; bedding plant
Identification (key features): best id by flowers (refer to diverse photos shown in post)
.Interesting facts: great variety results from dahlias being octopoid (eight sets of homologous chromosomes; most plants have two); they are the national flower of Mexico; grown as a food crop by the Aztecs
Cultivars: 
Dahlia merckii: -tough species (Botanical Group) – multi-branched, mid-green leaves of toothed leaflets, profuse broad-rayed lilac-pink flowers with yellow disc florets, 5′
D. ‘Twyning’s After Eight’ – AGM winner – long-flowering stylish (Single-flowered Group), ivory-white single flowers, strong stems,  almost black foliage, 3-4ft’
D. ‘Bishop of Llandaff’ – AGM winner – peony-flowered (Miscellaneous Group), almost black foliage, semi-double deep-red blooms, 3.25′
Comments: hybrid dahlias have been organized into ten (10) different classifications or groups (single, anemone, collarette, waterlily, decorative, fall, pompon, cactus, semi-cactus and miscellaneous)