Early, Large-flowered Clematis 'Asao'


Family: Ranunculaceae (ra-nun-kew-LAY-see-ee) (Info)
Genus: Clematis (KLEM-uh-tiss) (Info)
Cultivar: Asao
Hybridized by Ozawa
Registered or introduced: 1980
» View all varieties of Clematis


Early Large-flowered


8-10 ft. (2.4-3 m)


18-24 in. (45-60 cm)


USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

USDA Zone 5a: to -28.8 C (-20 F)

USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

Bloom Color:


Flower Fragrance:

No fragrance

Bloom Shape:



Bloom Diameter:

Large - 5 to 8 inches (12 to 20 cm)

Bloom Time:

Mid Spring

Sun Exposure:

Sun to Partial Shade

Other details:

Unknown - Tell us


All parts of plant are poisonous if ingested

Handling plant may cause skin irritation or allergic reaction

Pruning Groups:

Group 2 - Repeat bloomers; prune immediately after flowering

Patent Information:


Propagation Methods:

By air layering

By serpentine layering

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds

N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed

Foliage Color:

Unknown - Tell us

Bloom Characteristics:

Flowers are good for drying and preserving

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

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Where to Grow:

Unknown - Tell us


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


Capistrano Beach, California

Homer Glen, Illinois

Mt Zion, Illinois

Nilwood, Illinois

Oak Lawn, Illinois

Noblesville, Indiana

Sioux City, Iowa

Baton Rouge, Louisiana (2 reports)

Mandeville, Louisiana

Adamstown, Maryland

Brighton, Michigan

Trenton, Michigan

Minneapolis, Minnesota

Holts Summit, Missouri

Columbus, Ohio

Grove City, Ohio

Portland, Oregon

Milford, Pennsylvania

Mount Bethel, Pennsylvania

Pickens, South Carolina

Christiana, Tennessee (2 reports)

Crossville, Tennessee

Knoxville, Tennessee

Bulverde, Texas

Willis, Texas

Amelia Court House, Virginia

Cathan, Washington

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Gardeners' Notes:


On Jun 5, 2008, figaro52 from Oak Lawn, IL (Zone 5a) wrote:

This clematis tends to bloom heavily for me during the spring.


On May 18, 2006, merigold from Sioux City, IA (Zone 4b) wrote:

Planted 3 years ago. First two winters it got chopped down by somebody (bunnies I believe). But, always came back nicely. Last winter I protected the wood from the bunnies and this spring I'm getting a spectacular show. Packed with blooms!


On Jul 30, 2005, Marlina from Blaine, MN (Zone 4b) wrote:

I planted an asao in 2004 it didn't do much of anything the first year.It got one large bloom in the spring of 2005. I than cut it back to about 6 inches . It took off after that and reached about 10 to 15 feet or better and has about 20 flower buds on it right now 7/29/05. I am really excited about its second bloom...should be awsome..


On May 30, 2003, lupinelover from Grove City, OH (Zone 6a) wrote:

This cultivar, for me, seems to be prone to the clematis condition that makes the older stems die to the ground. It is vigorous in producing new ones, however, and it is a prolific bloomer. Reliably blooms from late April through mid May.


On Mar 23, 2003, viner wrote:

Shade roots to keep soil cool and moist.