Tree Dahlia
Dahlia imperialis

Family: Asteraceae (ass-ter-AY-see-ee) (Info)
Genus: Dahlia (DAHL-ya) (Info)
Species: imperialis (im-peer-ee-AL-is) (Info)
Hybridized by Roezl-Ortgies
Registered or introduced: 1863
» View all varieties of Dahlias

Section:

Botanical (species)

Flower Size:

Small - 4 to 6 inches (100 to 150 mm) diameter

Bloom Color:

Pink

Pruning:

Do not disbud

Height:

8-10 ft. (2.4-3 m)

10-12 ft. (3-3.6 m)

Spacing:

36-48 in. (90-120 cm)

Foliage:

Herbaceous

Smooth-Textured

Other details:

This plant is attractive to bees, butterflies and/or birds

Average Water Needs; Water regularly; do not overwater

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

Patent Information:

Non-patented

Propagation Methods:

By dividing rhizomes, tubers, corms or bulbs (including offsets)

From woody stem cuttings

Danger:

Parts of plant are poisonous if ingested

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds

Regional

This plant has been said to grow in the following regions:

Pelham, Alabama

Albany, California

Amesti, California (2 reports)

Brentwood, California

Clayton, California

Clovis, California

Culver City, California

Emeryville, California

Fairfield, California

Hayward, California

Los Gatos, California (2 reports)

Napa, California

Oakland, California

Richmond, California

San Francisco, California

San Jose, California

San Leandro, California

Santa Clara, California

Sebastopol, California

Stanford, California

Temecula, California

Boca Raton, Florida

Gainesville, Florida

Jacksonville, Florida

Panama City Beach, Florida

Venice, Florida

West Palm Beach, Florida

Yulee, Florida

Snellville, Georgia

Portland, Oregon

Saint Helens, Oregon

Vancouver, Washington

show all

Gardeners' Notes:

15
positives
1
neutral
0
negatives
RatingContent
Positive

On Feb 3, 2014, jv123 from Vancouver, WA (Zone 8b) wrote:

This dahlia grows to an incredible height, even it's first year in the ground. Planted in May, by Thanksgiving it was a good 12 feet high. The stems/trunks were about 4 inches in diameter, and the huge leaves did a great job of shading the ground. We did have a windstorm that knocked one of the trunks over, so I threw the severed stem in the compost pile. Little did I know it would continue growing... and 2 little stems shot up from the ground where the big one had fallen. Amazing! It provides a very nice lush tropical feel for my garden. This year I will be bracing the stems when they get taller than 6 feet.

Positive

On Apr 15, 2013, jonnyboy27 from winnipeg
Canada wrote:

my nana had ones of these at the front of her house in australia and it grew some 18 feet tall. i was un able to get a bulb when i cam back to canada and did not know it could be growen by cuttings. so i was looking all over for this and was wondering if there was a place i could get some cuttings? plese get back

Positive

On Apr 13, 2012, virescentthumb from Emeryville, CA wrote:

Bought this 'stick' at a UC Botanical Garden sale. It was worth the gamble at only $5. That was a couple of months ago and now it's starting to grow rather quickly. I finally looked at a few pics of what I might expect and I'm pretty excited. Hope it does okay close to a wall.

Positive

On Nov 20, 2010, Lbuers from Napa, CA wrote:

Love my Dahlia tree, it so nice to have something in bloom when tree loose their leaves. My plant is about 15'
talll and just started to bloom Nov 15. This is it first season in the ground, planted it in May. I had to stake it to my fence to stablize it. Now is doing great. Will try to graft cuttings this year. Wish me luck.

Positive

On Nov 17, 2010, SueSomit from Albany, CA (Zone 9a) wrote:

Three years ago, a neighbor gave me a "stick" of this plant and said to plant it at least 6 inches in the ground. Within a couple of weeks, I saw green growth on the top of the stick. Three to five branches survived and grew to have flowers. As noted above, branches can break in the wind. Bungy cords are great to stabilize the branches. I also have to cut off branches (starting at bottom and working up) because something is affecting the leaves. It starts out looking like brown stripes, takes over the whole leaf and turns it brown and brittle.

The neighbor also told me to cut the main trunk back to the ground when it was finished blooming and more would come up next year. I didn't do that, fearing my tree would die, and the next year's growth was spindly.

How... read more

Positive

On Jul 24, 2010, afviguy from Los Gatos, CA wrote:

hello all.just joined the site and also just got my first dahlia tree today given to me.wish me luck

Neutral

On Apr 29, 2010, BertieFox from Saumur
France wrote:

I have four tiny seedlings of this plant in my polytunnel from seed sown this year.
As we usually get frosts by November or December unless we are lucky (we're in France) I was thinking of growing one specimen at the front of a frost free conservatory which is a little on the shady size. The height of the conservatory is about ten feet. Would this be adequate? How large a pot should I give it? Would the shade inhibit flowering?
If I leave the rest in the garden until the first frosts, can I take up the tubers and overwinter like a normal dahlia? If I can and get these into early growth next year will this produce earlier flowering?

Positive

On Jan 1, 2010, kieffersrus from Watsonville, CA wrote:

I LIVE IN SANTA CRUZ, CA. IT'S IN THE CENTRAL COAST AREA OF CALIFORNIA,
ABOUT 75 MILES SOUTH OF SAN FRANCISCO. I HAVE BEEN GROWING TREE DAHLIA'S FOR YEARS AND SHARING THEM WITH FRIENDS.
THE BEST WAY TO PROPAGATE IS TO PLANT THE TRUNK/STEMS OF THE PLANT AT THE END OF THE SEASON, AFTER THEY HAVE BLOOMED AND AFTER THE LEAVES HAVE FALLEN OFF. THIS IS USUALLY AROUND DECEMBER IN MY AREA. I CUT THE TREES DOWN TO LEAVE ONE NOB, OF THE STEM, ABOVE GROUND. I THEN TAKE ALL OF THE CUT TRUNK/STEMS AND CUT THEM 2 INCHES BELOW EACH NOB AND LEAVE ABOUT 5 OR 6 INCHES ABOVE EACH NOB. YOU CAN THEN PLANT THE NOBS ABOUT 3 INCHES DEEP LEAVING THE LONG END ABOUT 2 OR 3 INCHES ABOVE GROUND. FOR THE BEST RESULT YOU SHOULD DAB EACH NOB WITH A ROOT STIMULANT. I PLANT THEM IN THE GROUND BUT YOU... read more

Positive

On Nov 30, 2009, passiflora_pink from Central, AL (Zone 8a) wrote:

In zone 8a it is a gamble whether I will be able to enjoy the November blooms before the frost hits. But it is worthwhile for its impressive, fast-growing foliage--it really changes a boring spot into a lush leafy focal point. And when it does bloom it is the talk of the neighborhood. I throw a couple of flakes of pinestraw over it that I fluff out over the root and don't bother digging it up to overwinter...so far it has done fine. The only problem is that deer relish it and prefer it to other shrubs in the garden.

Positive

On Nov 17, 2009, JaxFlaGardener from Jacksonville, FL (Zone 8b) wrote:

Dahlia imperialis continues to be one of my favorite plants in my botanical collection. There are few other flowering plants that can compete with the majesty and awe-inspiring beauty of this magnificent towering Dahlia. In my Zone 8b winters (with temperatures usually dropping down to just below freezing for several nights, but occasional dips down into the low 20s F), the Tree Dahlia dies back to the ground, but returns from the root crown each spring. It grows ever taller through the year, finally topping out at about 15 - 20 ft and begins flowering in mid-November.

Truly a splendid plant and always a conversation piece when I am providing garden tours.

You can find my DG article about Dahlia imperialis at ... read more

Positive

On Jan 23, 2009, turektaylor from Elizabeth City, NC (Zone 8a) wrote:

this plant is hardy from zone 7-9

Positive

On Jul 21, 2008, SierraTigerLily from Boca Raton, FL (Zone 10b) wrote:

I wasn't sure what would happen to this plant in zone 10a but it's been a wonderful experience. The plant flowers weekly and often has two or three blossoms at once swaying atop ten foot stalks. I have it caged against a sheltered wall where the wind cannot harm it. It also only receives brief midmorning sun. I wasn't sure when to cut it to the ground here as it never stops flowering. Now I just cut it when it starts to lean over too much onto the supports. It is a very delicate plant and new growth will curve away from the supports or any other stalks it touches.

Positive

On Mar 27, 2008, EarthMama from San Jose, CA (Zone 9b) wrote:

This plant has happy daisy-like flowers that seem to smile down at whomever is looking up at them! A friend gave me a cutting of a Tree Dahlia a year ago. I planted & supported it against an East-facing backyard fence, & it bloomed around Thanksgiving, when everything else was going to sleep. I was told to remove the new growth that forms at the "crotches" when the plant goes dormant in winter. I planted those in pots & gave them to some friends. Also, I was told to cut the plant to the ground when dormant, & it will come back. Since this is my first year with it, I was hesitant to do that, but I did cut it to the ground. My friend has assured me that it will come back . I'll let you know if it doesn't....

Positive

On Jan 18, 2006, jcangemi from Clovis, CA (Zone 9a) wrote:

I have had the same experience with it snapping off. Here in zone 9, it grows to great heights, 15 to 20 feet high some seasons. But if we have a strong summer windstorm, many branches will be damaged, some broken back to the main stump, others with side branches maimed. It tends to drop lower leaves gradually up the branches as the season progresses, but it's easy to clean up after. It flowers sometimes very early in the season before the heat hits, and then the biggest bloom comes at the end of summer, when it cools down. This specimen came from CA central coast and grows rank over there. I've never had a volunteer come up from seed, which are spread everywhere. It's either too hot or too cold after bloom I guess. Very beautiful foliage, the long branches sprouting from the main... read more

Positive

On Mar 27, 2005, MatthewCook from Pasadena, CA wrote:

Two years ago we found a neglected tree dahlia in our new back yard. It grows very quickly but is not very strong, so new shoots would grow out about 6 feet sideways before snapping and breaking under their own weight. Since I started supporting the branches it has done very well, growing over 20 feet high. The first year, it produced around 3 flowers. This year it produced somewhere around 200. Beautiful. After the flower fades, a brown "bud" of dry petals will appear. These petals blow off in the wind, carrying one seed per petal. It is easy to pluck the whole brown bud off (except they tend to be high up out of reach), but I do not know an easy way to separate the seeds from the petals. (It is easy to separate a seed from its petal, but there are over 100 seeds per bud so I don... read more

Positive

On Nov 27, 2004, doss from Stanford, CA (Zone 9b) wrote:

The tree Dahlia gets very tall, while not having many flowers, and they bloom late here. They are blooming here at Thanksgiving. The foliage is beautiful. I use it behind a fence and the flowers bloom just above it. My Dahlia actually grows between a fence and an olive tree, to keep it from blowing over. It seems to need very little sun to begin.