Siberian Iris 'Caesar's Brother'

Iris sibirica

Family: Iridaceae (eye-rid-AY-see-ee) (Info)
Genus: Iris (EYE-ris) (Info)
Species: sibirica (sy-BEER-ah-kuh) (Info)
Cultivar: Caesar's Brother
Hybridized by Morgan
Registered or introduced: 1932
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Siberian (SIB)


36-48 in. (90-120 cm)


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)

USDA Zone 9b: to -3.8 C (25 F)

Sun Exposure:

Full Sun


Parts of plant are poisonous if ingested

Handling plant may cause skin irritation or allergic reaction

Bloom Color:

Medium Purple

White/Near White

Bloom Time:

Late Midseason (MLa)



This plant is resistant to deer

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)

Patent Information:


Propagation Methods:

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

Seed Collecting:

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

Awards (if applicable):

Morgan-Wood Medal (SIB)

Foliage Color:

Medium Green

Bloom Characteristics:

Flowers are good for cutting

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

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Where to Grow:

Grow outdoors year-round in hardiness zone

Can be grown as an annual


This plant is said to grow outdoors in the following regions:

Brownsboro, Alabama

Mobile, Alabama

Georgetown, California

Mill Valley, California

Avon, Colorado

Brighton, Colorado

Denver, Colorado

Pensacola, Florida

Tampa, Florida

Barnesville, Georgia

Braselton, Georgia

Douglasville, Georgia

Marietta, Georgia

Rockford, Illinois

Fort Wayne, Indiana

Indianapolis, Indiana

Logansport, Indiana

Ewing, Kentucky

Hebron, Kentucky

Lexington, Kentucky

Morehead, Kentucky

Baton Rouge, Louisiana

South Berwick, Maine

South Paris, Maine

Attleboro, Massachusetts

Nantucket, Massachusetts

Roslindale, Massachusetts

Uxbridge, Massachusetts

Wayland, Massachusetts

Franklin, Michigan

Trenton, Michigan

Warren, Michigan

Andover, Minnesota

Hopkins, Minnesota

Lake City, Minnesota

New Prague, Minnesota

Lincoln, Nebraska

Omaha, Nebraska

Auburn, New Hampshire

Cranbury, New Jersey

Alden, New York

Bridgehampton, New York

Glen Head, New York

Phoenicia, New York

Concord, North Carolina

Graham, North Carolina

Greenville, North Carolina

Jacksonville, North Carolina

Wake Forest, North Carolina

Weaverville, North Carolina

Belfield, North Dakota

Columbia Station, Ohio

Columbus, Ohio

Warren, Ohio

Bend, Oregon

Portland, Oregon

Allentown, Pennsylvania

Meshoppen, Pennsylvania

Pittsburgh, Pennsylvania

Shamokin Dam, Pennsylvania

Wakefield, Rhode Island

Fort Mill, South Carolina

Hixson, Tennessee

Lafayette, Tennessee

Lenoir City, Tennessee

Coppell, Texas

Kerrville, Texas

San Antonio, Texas

Montpelier, Vermont

Lanexa, Virginia

Portsmouth, Virginia

Freeland, Washington

Kalama, Washington

Richland, Washington

White Center, Washington

Madison, Wisconsin(3 reports)

Waterloo, Wisconsin

Watertown, Wisconsin

Lander, Wyoming

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Gardeners' Notes:


On Dec 4, 2020, clanross from Lanexa, VA (Zone 7b) wrote:

I bought one of these on clearance from Bluestone. Purchased late, it didn't do much until the second season and then was very pretty. In November I needed to dig it up and move it and was able to divide it in to over TWENTY starter plants. I planted it in a somewhat soggy section of my vegetable garden with plenty of manure and it became a huge, healthy clump in less than 3 years. I will probably take a hit on this spring's blooms because of the dividing, but am looking forward to the big patch I'll have in a year or 2. I planted all but one starter plant inside the garden fence and put one outside to test its deer resistance.


On Apr 23, 2017, pb1234 from Mill Valley, CA wrote:

This took two years before it bloomed and it was worth the wait. The form is tall, slender and elegant, and the true purple blooms are dramatic. Very special.


On Apr 8, 2014, coriaceous from ROSLINDALE, MA wrote:

Siberian irises are first-rate garden perennials, tough and adaptable, and 'Caesar's Brother' is just a good a performer as it was eighty years ago when it was introduced.

However, there's been a great deal of progress in Siberian breeding since then. Check out the winners of the Morgan-Wood medal over the last twenty years to see even better irises, most with higher bud count, many with larger flowers, some with repeat bloom, and in a wider variety of colors :

As with all siberians, the narrow foliage is tidily upright during bloom season, and then gradually splays open as the season progresses, ... read more


On Apr 7, 2011, themikeman from Concord, NC (Zone 7a) wrote:

Ceasars Brother is a classic siberian iris..siberian iris sometimes take a couple years of growth to establish themselves i understand before they will bloom. i have only had mine a short time and it has not bloomed yet but it is healthy and vigorous in terms of vegatative growth. my friend sheila in illinois has grown this for close to three decades and it has spread across the whole back half of her huge property..the pics she sent me of her hundreds of blue-purple blooms were breathtaking..mike


On Jul 18, 2010, ldekker from Daly City, CA wrote:

I had 2 plants installed into my landscape last fall.
By spring the green leaves began to shoot up.
I watched and watched and finally found some faded blooms had appeared. I missed their bloom because they bloomed near the ground level.
Does this mean they were planted to deep or are they just young plants? They are on a drop irrigation, in foggy Daly City California. I am hoping year two will be better.


On May 10, 2009, dreamgreen from Weaverville, NC wrote:

This is one tough & persistant iris. Beautiful too. I transplanted my Caesar's Brother from a field that was an old home site. The house was torn down in the 1950s but this iris remained and bloomed among blackberry vines and tall grass with no care for half a century! It is identical to the other 'Ceasar's Brother' irises that I have grown for years. It was hybridized by Morgan and was the Morgan award winner in 1953.


On Feb 26, 2009, pinballer3 from Homosassa, FL (Zone 9a) wrote:

This Iris has thrived in alkaline clay soil with drip line watering in summer for four years. Last year, there were 8-10 blooms on each clump. The plant gets full hot sun on a southern slope in summer but is shaded by the house in winter. Looks like its time to divide them now, as the centers are just now thinning out. This is a hearty plant with spring flowers that always get compliments!


On Apr 26, 2008, konijntje from Seattle, WA (Zone 8a) wrote:

This plant has been a phenomenal success under the most oppressive conditions. We have a steeply sloping concrete driveway which channels rivers of water down to the bottom any time we get a Georgia cloudburst. This leaves the bottom of the drive flooded and filled with the soil the water brought down with it. We dug a swale at the edge of the yard next to the driveway bottom to drain the water and silt out of the drive, which it does. However, this swale area goes from one awful condition to the other (arid clay in the unrelenting full sun most of the time to swamped and silty after a rain). On the advice of the folks at Triple Creek Flower Farm (see DG Garden Watchdog) last September, we planted several miscanthus and several Caesar's Brother iris in that swale after adding moderate so... read more


On May 28, 2006, dmj1218 from west Houston, TX (Zone 9a) wrote:

This variety of siberian iris performs well in Houston, Texas.


On Jun 9, 2005, Tjsangel from Warren, OH wrote:

One of my favorite iris. Lots of deep purple blooms, foliage is also beautiful. Likes some moisture. Dependable.


On Aug 22, 2003, awatson from Wayland, MA wrote:

Also Groundhog resistant.


On Jun 22, 2003, carolann from Auburn, NH wrote:

One of early summer's most dependable blooms here in z5. Beautiful color and high bud count.