YardMate
English
Download
Tree Dahlia (Dahlia imperialis), whole plant
  • Tree Dahlia — close-up of leaves and flowers
  • Tree Dahlia — seasonal appearance
  • Tree Dahlia in a garden setting

Tree Dahlia

Dahlia imperialis

Medium · Some experience

About Tree Dahlia

Tree Dahlia is a giant perennial dahlia native to Mexico and Central America, sending up hollow bamboo-like stems 10-20 feet tall topped with nodding sprays of pink or lavender daisy-like flowers in late autumn. A spectacular architectural specimen for frost-free American gardens (USDA 8-11), especially popular in coastal California and the Southeast. Dies to the ground after frost but resprouts vigorously.

  • Architectural
  • Pollinator-friendly
WATER
Regular
Top inch dry
LIGHT
Full sun
6+ hrs direct
HARDY
Hardy to 10°F (-12°C)
USDA hardiness zones 8–11

How to care for Tree Dahlia

Watering

  • Springevery 4 days
  • Summerevery 3 days
  • Fallevery 5 days
  • Winterpause watering

Soil · Well-draining

  • Main mixLoam + coarse sand 3:175%
  • DrainageGravel25%

Sharp drainage matters most — bulbs rot in wet soil while dormant.

FERTILIZER

Balanced Feed 14-14-14

An even feed covers all three needs at once, keeping leaves, roots and blooms moving together with nothing pushed out of balance.

N33%P33%K33%
  • Nitrogen · Leaves
  • Phosphorus · Roots + Blooms
  • Potassium · Strength
  • Springevery 21 days
  • Summerevery 21 days
Get watering reminders for Tree Dahlia — free on iPhoneDownload on the App Store

At a Glance

  • NativeCentral America
  • Height15–25 ft (4.6–7.6 m)
  • Spread4–8 ft (1.2–2.4 m)
  • Flower colorPink, Purple, White
  • Foliage colorGreen
  • SoilWell-drained, Loamy, Rich
  • LocationsYard

Bloom time

BLOOM CYCLE

Peak bloom

Nov–Dec

J
F
M
A
M
J
J
A
S
O
N
D

Pink or lavender sprays November to December

Toxicity

Pets Slight

Unknown toxic principle

Not reported

EXPOSURE No exposure route is reported.

EFFECT No toxic effect is reported.

NOTE No human toxicity is reported in this catalog; avoid eating ornamental plants unless confirmed edible.

Slight

  • All
  • Ingestion

EXPOSURE Eating any part of the plant.

EFFECT Mild vomiting.

NOTE ASPCA: mildly toxic to pets.

Slight

  • All
  • Ingestion

EXPOSURE Eating any part of the plant.

EFFECT Mild vomiting.

NOTE ASPCA: mildly toxic to pets.

Educational information, not medical or veterinary advice. If exposure is suspected, contact a doctor or veterinarian.

DISTRIBUTION

Tree Dahlia · Native
  • Native
  • Introduced
  • Central America

History

Illustrated historical scene for Tree Dahlia

Dahlia imperialis is a remarkable arborescent dahlia growing to 20 feet tall in its native montane forests of Mexico, Guatemala, Honduras, and Colombia. German-Dutch botanist Franz Julius Ferdinand Meyen described it in 1839, though living plants did not reach European cultivation until around 1863 through French horticulturists. The species develops thick bamboo-like canes from tuberous roots and only flowers in late autumn as day-length shortens, making it challenging outside USDA zones 9-11 where frost kills the canes before blooming.

In suitable climates including coastal California, the Bay Area, and the southern US, it creates spectacular late-season displays of pendant lavender-pink flowers. Indigenous peoples used the hollow canes as water conduits, and the stout stems can be rooted to propagate new plants.

Iconic in Golden Gate Park and many coastal California gardens where its autumn bloom spectacle is legendary. A signature plant of subtropical American landscape design, often paired with tropical foliage and late perennials.

Symbolism & meaning

What It Symbolizes

The Tree Dahlia is Grandeur on a stem — bamboo-thick stalks lifting lavender flowers fifteen feet into the autumn sky. Its heritage reaches back to Aztec gardens, where dahlias were grown long before the European world knew them. Each bloom is a tall, late-season echo of an older botanical empire.

  • Grandeur — towering architectural stature
  • Heritage — historical Aztec cultivation

Where the Name Comes From

'Imperialis' means 'imperial', reflecting the regal scale of the plant.

Uses & Fun Facts

  • Tree dahlia towers above garden with late-autumn pink flowers
  • Bamboo-like canes topped by huge nodding blossoms
  • Dramatic stems for large-scale fall arrangements

Related plants

More Dahlia plants

Plants with similar care

Frequently asked questions

How often should I water Tree Dahlia?

Water about every 4 days during the growing season, and always let excess water drain away.

How much light does Tree Dahlia need?

Full sun: 6+ hrs direct. Watch the leaves — scorching or stretching means the light needs adjusting.

Is Tree Dahlia toxic to cats or dogs?

Pets Slight (Dogs Slight · Cats Slight) Educational information, not medical or veterinary advice. If exposure is suspected, contact a doctor or veterinarian.

Is Tree Dahlia easy to grow?

It is moderately demanding: a good choice once you have a little experience.

When does Tree Dahlia bloom?

It typically blooms Nov–Dec in the Northern Hemisphere.

YardMate

Identify any plant in seconds

Snap a photo — YardMate names the plant, diagnoses problems, and reminds you when to water.

Download on the App Store
YardMateIdentify · Diagnose · Remind
Download