Photo of Dahlia imperialis flower by Annie's Annuals & Perennials

Photo by Annie's Annuals & Perennials

Used with permission, all rights reserved

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Dahlia imperialis

Also Known As

  • Giant Tree Dahlia
  • Tree Dahlia

Plant type

perennial, bulb / corm / tuber

size

  • H: 17'-25'
  • W: 7'-15'

planting zones

  • 7a-9b

More Options

Dahlia imperialis plant details

Dahlia imperialis is a broadleaf deciduous or semi-evergreen perennial bulb / corm / tuber with green foliage. In fall and summer lavender and pink flowers emerge. Attracts bees and hummingbirds making it an excellent addition to pollinator gardens. Grows well with sun - mostly shade and even moisture water. Does well in rich and well-drained soil.

CHARACTERISTICS OF Dahlia imperialis

Plant type: perennial bulb / corm / tuber
Plant family: asteraceae
Foliage: deciduous or semi-evergreen green
Mature size: 7 FT - 15 FT - wide, 17 FT - 25 FT - tall
Flowers: lavender and pink blooms in fall and summer

GROWING CONDITIONS for Dahlia imperialis

USDA Zones: 7a - 9b
Sun exposure: sun - mostly shade
Watering frequency: even moisture
Soil needs: rich and well-drained

Nursery contributed plant descriptions

The Tree Dahlia is the tallest member of the Dahlia genus and is native to high elevations in Mexico and Central America. Because of its upland habitat, this species is surprisingly cold hardy and flourishes in many temperate climates. Rapidly reaching heights of up to 20 feet in one season, you can literally watch the canes grow throughout the day. The Tree Dahlia has tubers and will die down during the winter making over-wintering similar to other Dahlias. Cold hardy to zones 7b and above.
If you've heard of "tree dahlias" these are the plants being referenced. Maturing to a huge 8-18 feet in a single season, Dahlia Imperialis looks like nothing you've ever seen before. Six inch pink flowers are held in loose groups that are 2-3 feet across. Plant where growing season are very long (or extend the season by starting indoors) - these dahlias need 7-8 months to blooms. Some gardeners grow for the bamboo-like stems and use for landscape effect. Happy in mild West Coast locations where they grow with wild abandon. Why Grow Dinnerplate Dahlias? Few flowers offer the color and form diversity of dahlias Dahlias are garden showgirls; this variety easily reaches the eaves of a ranch home. Stake plants to support super tall stems and flowers; see Dahlia Planting Guide for tips Dahlia tubers can be saved, divided and shared. Click on the Dahlia Planting Guide button, right, for details and growing tips.

By: Leafari

This rather imposing tree dahlia reaches roof height (12-15 ft a season). The pink flowers are always a gamble, though. It blooms after Thanksgiving and only in mild years will it not frost before bloom. Half sun, normal water. Stake it.
Tree Dahlia. I mean it - TREE Dahlia. This holdover from the Pleistocene reaches 20' tall with good rich soil making impressive Bamboo-like clumps with very thick stems. The flowers are the size of garbage can lids - no I'm kidding but they should be. Average size and pale lavender.
A real traffic stopper! This magnificent species Dahlia from Central America grows like a weed here in California. So why is it so hard to find? To at least 8' tall, it can reach 20' when happy. In areas with cold Winters, some gardeners include this monstrous beauty just for its foliage! The tall canes are bamboo like, with lush leaves. The flowers, though, the flowers!! Each lavender pink bloom can span up to 6” & the massive flowering panicles can be 3' across - and mind you that is per stalk! Large plants can produce an abundance of flowers both alarming & astounding when you stand underneath them in full bloom & see them all looking down at you. Wonder! Cut back to 6” after it has finished blooming. Cold hardy and tough as nails.

Gardening facts about Dahlia imperialis plant

How to Grow Dahlia imperialis

  • Sun Exposure

    • sun - mostly shade
  • Water Needs

    • even moisture
  • Soil Needs

    • well-drained
    • rich

Features

  • Foliage Color

    • green
  • Flower Color

    • pink
    • lavender
  • Wildlife

    • bees
    • hummingbirds
  • Flower Season

    • fall
    • summer
  • Foliage Season

    • deciduous
    • semi-evergreen

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