Photo by Melody

PlantFiles: Sunflower
Helianthus annuus 'Mammoth'

Family: Asteraceae (ass-ter-AY-see-ee) (Info)
Genus: Helianthus (hee-lee-AN-thus) (Info)
Species: annuus (AN-yoo-us) (Info)
Cultivar: Mammoth
Additional cultivar information: (Mammoth Russian, Russian Mammoth, Black Russian)

5 vendors have this plant for sale.

48 members have or want this plant for trade.


12-15 ft. (3.6-4.7 m)

24-36 in. (60-90 cm)

Not Applicable

Sun Exposure:
Full Sun


Bloom Color:
Bright Yellow

Bloom Time:
Mid Summer


Other details:
Unknown - Tell us

Soil pH requirements:
5.6 to 6.0 (acidic)
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)
7.6 to 7.8 (mildly alkaline)

Patent Information:
Unknown - Tell us

Propagation Methods:
From seed; direct sow after last frost

Seed Collecting:
Collect seedhead/pod when flowers fade; allow to dry

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There are a total of 20 photos.
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4 positives
3 neutrals
1 negative

Gardeners' Notes:

Negative YosemiteJunkie On Jul 12, 2014, YosemiteJunkie from Carrollton, GA (Zone 7b) wrote:

These were grown in Hard Clay in zone 7B and I don't know if the seeds were a bad batch or not. I got them at Walmart. But all the flowers turned out deformed with weird shapes and quickly bowed their heads to the ground once bloomed.

Positive Lovehum On May 13, 2014, Lovehum from (Zone 6b) wrote:

American goldfinches and even some red cardinals ate the seeds in autumn and winter. Unfortunately they'll attract aggressive house sparrows too.

Neutral jjstatz29 On Oct 14, 2013, jjstatz29 from Elk Horn, IA (Zone 5b) wrote:

Positive: huge easy to grow impressive plant that will have your neighbors concerned and/or extremely interested

Negative: topples easily and those stems are ... challenging to deal with (get out the machete... or better yet the chainsaw)

Positive: Huge amount of seed from one plant for eating, gifting, and planting next year

Negative: insignificant petals (relative to size) that are extremely short lived.

Positive Dosetaker On Sep 3, 2012, Dosetaker from Mason, NH (Zone 5b) wrote:

Planted ours a bit late and as such they did not grow to the common monster proportions they are known for...but they still gave us very beautiful flowers on stalks that reached about the five foot mark.

Neutral CCPikie On Aug 20, 2011, CCPikie from Elmhurst, IL wrote:

These grew well in my poor soil. Should have followed advice to plant in stages to assure longer bloom. My only complaint is the short life of the flower. It's perfect for only a few days, then bows and faces the ground. Bought seed from Ferry-Morse.

Positive CurtisJones On Nov 3, 2008, CurtisJones from Longmont, CO wrote:

From your friends at Botanical Interests: Towering in the garden at 6'-10' tall, these Mammoth (also called Mammoth Russian) sunflowers often have seed heads that are up to 1' across! This popular heirloom variety has been grown in gardens since the late 1800's. You can grow them for use as cut flowers - (one flower would fill a vase), as a fun fast-growing variety for a kid's garden, to eat the abundant sunflower seeds, or to provide winter fare for birds. (Note: Start from seed indoors 4-6 weeks before transplanting outside if you have trouble with birds or other critters eating your seeds or young seedlings outdoors.)

Neutral atrotasha On Jun 25, 2008, atrotasha from New Port Richey, FL (Zone 9b) wrote:

These are great, you just have to watch them when they are small because the animals like them. Last year mine got eaten one night. It was there when i went to bed and the next day it was gone and the stalk had chew marks all over it. When that does'nt happen, growing sunflowers is very rewarding.

Positive blondemommyof2 On Sep 19, 2004, blondemommyof2 from Lititz, PA (Zone 6a) wrote:

Great sunflower kids love it and it attracts lots of birds!~


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

College, Alaska
Phoenix, Arizona
Batesville, Arkansas
Blytheville, Arkansas
Los Angeles, California
Sacramento, California
San Diego, California
Aurora, Colorado
Denver, Colorado
Longmont, Colorado
Jacksonville, Florida
Naples, Florida
Augusta, Georgia
Carrollton, Georgia
Lilburn, Georgia
Roopville, Georgia
Chillicothe, Illinois
Elmhurst, Illinois
Elk Horn, Iowa
Shawnee Mission, Kansas
Wichita, Kansas
Bethelridge, Kentucky
Lewisburg, Kentucky
Battle Creek, Michigan
Macomb, Michigan
Natchez, Mississippi
Hallsville, Missouri
Las Vegas, Nevada
Silver Springs, Nevada
Greenville, New Hampshire
Piscataway, New Jersey
Roswell, New Mexico
Campbell Hall, New York
Staten Island, New York
Raleigh, North Carolina
Columbia Station, Ohio
Niles, Ohio
Hulbert, Oklahoma
Bend, Oregon
Wilsonville, Oregon
Allentown, Pennsylvania
Kingston, Pennsylvania
Coventry, Rhode Island
North Augusta, South Carolina
Brazoria, Texas
Edinburg, Texas
Fort Worth, Texas (2 reports)
Pearland, Texas
Round Rock, Texas
San Antonio, Texas
Farmington, Utah
Magna, Utah

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