• Image of Dahlia imperialistaken at Juniper Level Botanic Gdn, NC by JLBG
  • Image of Dahlia imperialistaken at Juniper Level Botanic Gdn, NC by JLBG
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Dahlia imperialis

Giant Tree Dahlia

This plant is not currently for sale. This is an archive page preserved for informational use.

Shop Available Dahlia
1 Review
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Item #: 4724

Zones: 7b to 9b

Dormancy: Winter

Height: 108" tall

Culture: Sun

Origin: Central America

Pot Size: 3.5" pot (24 fl. oz/0.7 L)


I have this fetish for growing peculiar things, and the giant tree dahlia is at the top of my list. In the wild, Dahlia imperialis can reach 30', but our garden plants only reach a meager 9' in height. The bamboo-looking stalks easily grow to a massive 3" in diameter and are topped with oversized but typical dahlia foliage. If you garden in Zone 7a, you can forget flowers, which are single pink and always manage to open the day we have our first killing frost. Nevertheless, this tropical-looking gem is worth growing just for its stature and texture in the garden...and to fool all your neighbors with its identity. Have someone take your photo standing alongside your dahlia, and you're a sure-fire winner for the next Miracle-Gro commercial.

Maintenance:

Cut this plant to the ground after frost has killed it. This is about all the maintenance that it requires. Despite its great height it most often manages to stand up without assistance.

Growing Conditions:

Full sun and good drainage. It does not need sharp drainage, just avoid soggy sites. Killing frosts in the fall are now quite a bit later than they were 20 or 30 years ago and Dahlia imperialis does now some years manage to bloom out fully.

Garden Value:

Yes indeed Dahlia imperialis adds some WOW factor to your garden with its amazing height and floral display. The floral display is stunning when it occurs. Great horizontal side branches, way over head, bear saucer sized pendant flowers. That the flowers are pendant means that they are looking down at the earthbound viewer which is much better than looking up at the underside of the flower heads. Long before a tree dahlia blooms the plant itself has a big bold architectural presence in the garden with its sturdy trunks and layers of large compound leaves.

Natural Impact:

Tree dahlias bloom so late in the year it might not support many pollinators, though should one be passing through the garden they would make use of the flowers when so few other plants are in bloom.