Buddleja, Butterfly Bush, Orange-Eye Butterflybush, Summer Lilac 'Black Knight'

Buddleja davidii

Family: Scrophulariaceae (skrof-yoo-larr-ee-AY-see-ee) (Info)
Genus: Buddleja (BUD-lee-uh) (Info)
Species: davidii (duh-VID-ee-eye) (Info)
Cultivar: Black Knight
View this plant in a garden



Water Requirements:

Drought-tolerant; suitable for xeriscaping

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Full Sun




Foliage Color:

Unknown - Tell us


4-6 ft. (1.2-1.8 m)

6-8 ft. (1.8-2.4 m)


6-8 ft. (1.8-2.4 m)


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)

USDA Zone 10a: to -1.1 C (30 F)

USDA Zone 10b: to 1.7 C (35 F)

Where to Grow:

Grow outdoors year-round in hardiness zone

Can be grown as an annual



Bloom Color:

Dark Purple/Black

Bloom Characteristics:

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

Flowers are fragrant

Bloom Size:

Unknown - Tell us

Bloom Time:

Mid Summer

Late Summer/Early Fall

Mid Fall

Blooms repeatedly

Other details:

May be a noxious weed or invasive

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

6.6 to 7.5 (neutral)

7.6 to 7.8 (mildly alkaline)

Patent Information:


Propagation Methods:

From semi-hardwood cuttings

Seed Collecting:

Allow seedheads to dry on plants; remove and collect seeds


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

Enterprise, Alabama

Gulf Shores, Alabama

Wetumpka, Alabama

Anthem, Arizona

Flagstaff, Arizona

Phoenix, Arizona

Prescott Valley, Arizona

Dermott, Arkansas

Gentry, Arkansas

Berkeley, California

Brea, California

Chico, California

Clayton, California

Crescent City, California

Crockett, California

Elk Grove, California

Fairfield, California

Fremont, California

Hesperia, California

Knights Landing, California

Long Beach, California

Madera, California

Merced, California

Paradise, California

Pittsburg, California

Redondo Beach, California

Sacramento, California(2 reports)

Upland, California

Valley Center, California

Parker, Colorado

Seymour, Connecticut

Sherman, Connecticut

Bear, Delaware

Lewes, Delaware

Wilmington, Delaware(2 reports)

Fort Walton Beach, Florida

Merritt Island, Florida

Oldsmar, Florida

Orange Park, Florida

Palm Coast, Florida

Saint Cloud, Florida

Sebring, Florida

Spring Hill, Florida

Tallahassee, Florida

Trenton, Florida

Barnesville, Georgia

Conyers, Georgia

Cordele, Georgia

Dacula, Georgia

Lawrenceville, Georgia

Potlatch, Idaho

Chicago, Illinois(2 reports)

Godfrey, Illinois

Mackinaw, Illinois

Rockford, Illinois

Anderson, Indiana

Fort Wayne, Indiana

Sheffield, Iowa

Kingman, Kansas

Perry, Kansas

Barbourville, Kentucky

Frankfort, Kentucky

Hebron, Kentucky

Lexington, Kentucky

Smiths Grove, Kentucky

Plain Dealing, Louisiana

Aberdeen, Maryland

Upper Marlboro, Maryland

Franklin, Massachusetts

Pembroke, Massachusetts

Sterling, Massachusetts

Topsfield, Massachusetts

Wellesley, Massachusetts

Bay City, Michigan

Dearborn Heights, Michigan

Pinconning, Michigan

Stanwood, Michigan

Warren, Michigan

Saint Paul, Minnesota

Mathiston, Mississippi

Saint Louis, Missouri

Henderson, Nevada

Las Vegas, Nevada

Auburn, New Hampshire

Greenville, New Hampshire

Manchester, New Hampshire(2 reports)

Jamesburg, New Jersey

Johnsonburg, New Jersey

Stanhope, New Jersey

Kirtland, New Mexico

Roswell, New Mexico

Elba, New York

Jefferson, New York

Port Washington, New York

Poughkeepsie, New York

Broadway, North Carolina

Candler, North Carolina

Carthage, North Carolina

Chapel Hill, North Carolina

Elizabeth City, North Carolina(2 reports)

Murphy, North Carolina

Oxford, North Carolina

Raeford, North Carolina

Raleigh, North Carolina

Dayton, Ohio

Felicity, Ohio

Glouster, Ohio

Saint Marys, Ohio

Westerville, Ohio

Edmond, Oklahoma

Chiloquin, Oregon

South Beach, Oregon

Tillamook, Oregon

Albion, Pennsylvania

Allentown, Pennsylvania

Ambler, Pennsylvania

Beaver Falls, Pennsylvania

Brookhaven, Pennsylvania

Greensburg, Pennsylvania

Philadelphia, Pennsylvania

Pittsburgh, Pennsylvania

Reading, Pennsylvania

Souderton, Pennsylvania

Wood River Junction, Rhode Island

Bluffton, South Carolina

North Augusta, South Carolina

Sumter, South Carolina

Greeneville, Tennessee

Oliver Springs, Tennessee

Toone, Tennessee

Alice, Texas

Austin, Texas

Boerne, Texas

Bryan, Texas

Bulverde, Texas

Copperas Cove, Texas

Fort Worth, Texas(2 reports)

Houston, Texas

Irving, Texas

Lewisville, Texas

Liberty Hill, Texas

Lindale, Texas

Mabank, Texas

Richmond, Texas

San Antonio, Texas

Farmington, Utah

Ivins, Utah

Kaysville, Utah

Salt Lake City, Utah(2 reports)

Alexandria, Virginia

Herndon, Virginia

Portsmouth, Virginia

Richmond, Virginia

Sterling, Virginia

Concrete, Washington

Grand Mound, Washington

Kalama, Washington

La Conner, Washington

North Bend, Washington

Quincy, Washington

Rochester, Washington

Seattle, Washington(3 reports)

Vancouver, Washington(2 reports)

Petersburg, West Virginia

Cambridge, Wisconsin

Milwaukee, Wisconsin

South Milwaukee, Wisconsin

Riverton, Wyoming

show all

Gardeners' Notes:


On Aug 24, 2019, Rests from Bryan, TX wrote:

The information on the plant says to plant in full sun, but it seems to hate the full sun in Central Texas. I planted 3 of them where they would get a few hours of full sun. They wilt really bad, the tips of the leaves are turning brown. Look to be slowly burning up. I really don't think they do well past Zone 7. Or full sun really means part sun here in extremely hot Texas.


On Jun 17, 2018, Kitkatz from Edmond, OK wrote:

Its now mid June in hot, central Oklahoma. I forgot to prune my butterfly bush to the ground and whats growing now looks pretty sad. Is it too late to cut it down now? I dont want to kill it but its not doing much as is. Thanks!


On Jun 5, 2017, floramakros from Sacramento Valley, CA wrote:

My favorite butterfly bush! If you want a plant as tall as a tree with giant stunning blooms that explode with color every time the sunlight hits them and grow bigger and more numerous each successive season this is the one for you. A definite show stopper! In shade or on dark cloudy days the blooms appear black. What a beauty!


On Aug 1, 2016, coriaceous from ROSLINDALE, MA wrote:

In my observation, this is one of the tallest Buddleia davidii cultivars, and its flowers are the most deeply colored of any, a clear rich blue-violet. The inflorescences are large. It can reach 8-10' tall here even when cut back hard in early spring.

The Royal Horticultural Society has given this cultivar its coveted Award of Garden Merit. http://apps.rhs.org.uk/planttrials/TrialReports/Buddleja 201...

Like all B. davdii cultivars, this requires weekly deadheading for it to look and bloom its best.

Buddleias are fairly short-lived shrubs, 5-10 years is common.

In some places, B. davidii can be an invasive weed: England, F... read more


On Jan 8, 2014, kmm44 from Dayton, OH wrote:

I have 3 of these at my main home and one at the lake house. I love them! They bloom for a long time with minimal deadheading and, if pruned well, do not spread. The butterflies love them, too, and at times are covered with them.
I looked at the neutral and negative responses and think it must be the areas that are causing problems. Here in SW and NC Ohio we do have heat and drought at times, but not prolonged.
I love the dark purple color. Once established they don't need constant watering. I use them as a backdrop or centerpiece for other perennials in layered heights.


On Jan 6, 2014, wakingdream from Allentown, PA wrote:

Our Black Knight butterfly bush was quite lovely for several years, but succumbed to encroaching shade. We cut it back to about 12" annually in late winter, and it successfully resprouted to a manageable size, but eventually it did not return for us. The color of the flowers was dramatic, with a fragrance so rich it was almost culinary. Monarch butterflies were regular visitors as were Yellow Swallowtails and Mourning Cloaks. The offspring of this plant bloomed medium purple 90% of the time.


On Jan 6, 2014, snorklewort from Conyers, GA wrote:

Does not like wet feet, do a raised bed if in a wet clay area. Beautiful with low growing yellow lantana under planted.


On Jul 18, 2013, bobbieberecz from Concrete, WA wrote:

LOVE this bush!! It likes at least some water and will pout if it dries out in my sandy-loam soil. My Black Knight grew very quickly to at least 15 feet, is covered with large (well over a foot) wonderfully scented panicles. I also have this plant in raspberry (beautiful and almost as vigorous), yellow (a more "bushy" shape with smaller, less fragrant flowers), and lavender (after pruning this spring it grew 6 feet in just a few months!). I have 5 acres and if I or my friends want a bush, I just put a branch into the ground and let it get watered with the rest of the flowers. Ignore it if the leaves fall off. By next spring you'll have another bush to share. Black Knight is the easiest of all to root and grows jubilantly right from the start. I have one happy bush in all day dappl... read more


On Feb 13, 2013, Gardeningman from Kingman, KS (Zone 6b) wrote:

I had planted two of these the spring of 2013 right next to my lantana flower bed. However, both last year and this year they were infested by spider mites. I tried to treat them but couldn't seem to get on top of the problem. After the spider mites began to spread to my Froebelli Spireas, I decided that it was time for the butterfly bushed to go, so I shovel pruned them.


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

As with most Butterfly Bush, this is a great plant. Nice dark color and that thick scent that fills the air. Brings in the butterflies in droves.


On Sep 1, 2012, Mike_W from Sterling, MA wrote:

Great plant! I have 4 of them out in my garden and the bees and butterflies go nuts for the flowers. Butterflies will swarm all over the blooms and when they try to fly away, they can't help but turn around and come right back. I plan on getting a few more in different colors and planting them along a fence.


On Apr 1, 2012, Sandwichkatexan from Copperas Cove, TX wrote:

I hack these to the ground every year . They are the backbone of my largest flowerbed . I have them underplanted with cuphea ignea , king alfred type daffodils , phlomis russelana , several smaller growing agaves , variegated yucca, iris pallida variegata , katie ruellia , coryopsis route 66, salvia greggi of all colors , ham an egg lantanas , tecoma stans , golden splendor lilies , foxtail lilies , and two ocotillos for accent . This is my knockout flowerbed when its in full bloom it is amazing and hummingbird turf wars frequently break out .


On Jul 8, 2011, joey62 from Gun Barrel City, TX wrote:



On May 3, 2011, virginiarose from Portsmouth, VA (Zone 8a) wrote:

My bush was up to ten feet high last year before the first frost. I almost never watered it because it was on the back side of garage where hose will not reach. It responds very well to pruning and dead-heading. :)


On Sep 7, 2010, suentommy from Souderton, PA (Zone 6b) wrote:

I planted one of these bushes about twenty years ago. I think that one died - but it is hard to tell since I now have about ten of them - none which I have planted. They are beautiful in bloom and if you dead head them the flowers just keep on coming. Butterflies, bees, and hummingbirds love them. It is a real treat to watch them from my office window all day as they move between those, crape myrtles, and heptacodium trees. They bloom from mid summer to late fall. They don't seem to die back here, but in the years I forgot to cut them back to about a foot or two the bushes became unruly, huge, and not very attractive. Lesson learned. Remember to cut them back if you want them to remain attractive. They have brittle wood, especially on older plants that will split. I don't know if ... read more


On Aug 22, 2010, bariolio from Houston, TX (Zone 9a) wrote:

Have 3 of these planted in full sun. They are really struggling in the intense heat this summer. The leaves turn yellow with brown spots, ends get brown and crunchy (dead!) and fall off. We just put a shade over them in hopes that they will survive. I LOVE this color and will replace them if they don't make it. Will update if I remember!


On Jul 25, 2010, CouchHogs from Rockford, IL (Zone 5a) wrote:

I am loving this plant. Never seen so many different butterflies. I deadhead often to ensure it has fresh flowers for them. Yay!!

I do have seeds for trade-see my trade list.


On Oct 13, 2009, RussS from Saint Louis, MO wrote:

I find it interesting that the state of Oregon will ban the Buddleja plants because the plants are considered invasive. While I agree that the plants can be propogated from the seed quite easily, I do not agree that the nurseries should benefit from this decision. A similar situation has taken place with new varieties of corn that will not reproduce from the seed. Where are we headed if we try to re-engineer nature? I collect the butterfly seeds and have spread them around my garden. Each year a handful of new plants appear, but they do not appear to be taking over the world. I hope to some day have many more of these bushes and continue to attract more butterflies. This is one of my favorite plants in my garden.


On Jul 19, 2009, ospreyhome from Chiloquin, OR wrote:

This shrub dies back to the ground in my area (z5) and Butterfly Bush 'Nanho Blue' does much better. All Buddlejas will be banned for sale in Oregon by the end of 2009.


On Jul 13, 2009, khabbab from lahore,
Pakistan (Zone 10b) wrote:

This is a difficult plant to grow in lahore Pakistan as it does not tolerate hot summer here. I have planted one in a clay pot with lots of mulching and it just survived our 45c hot summers. Growth is retarded but has resumed in mid july with start of rainy season. Have not seen it bloom yet. It grows easily in hilly areas specially in murree and blooms well there.


On Sep 10, 2008, Bookerc1 from Mackinaw, IL (Zone 5a) wrote:

Our Black Knight is in its second year, and is really thriving. The blooms are much larger and fuller than last year. I've found that it is so irresistible to butterflies and bees that they will fly all around me when I am weeding at its feet. I've turned my head and found them just beside me, so absorbed in it's fragrance they they don't even seem to notice me there. I understand. . .I can get lost with my nose buried in one, too!

Has anyone saved seed and successfully grown it out?


On May 24, 2008, CharmingGarden from Tallahassee, FL (Zone 8b) wrote:

I really like this plant and flowers are non stop until the winter time. I deadhead all the spent blooms just to promote new blooms which seems to work well. However, the color of the blooms have gone from dark purplish-blue to pinkish magenta. Has anyone else experienced this?


On Feb 5, 2008, DATURA12 from Fort Worth, TX (Zone 8a) wrote:

I love these plants, they attract tons of butterflies and are really easy to propagate by cuttings any time of the year. I deadhead constantly and cut it back late winter by one third.


On Oct 9, 2007, soapwort243 from South Milwaukee, WI wrote:

I have a couple of these. For me, every year they get shorter - (maybe a little) but and they get alot wider. I cut all the way to the ground in late fall.(which was what I told when I purchased because the new growth comes out of the ground.) Every year I think that they died over winter because they do not show any life until the end of May-beginining of June. The best thing about them is that they really do attract LOT of butterflies and bees !!!


On Sep 18, 2007, BlackDogKurt from Seymour, CT wrote:

Beautiful shrub. It really does attract tons of butterflies! I deadhead the spent blooms to encourage more blooms, which will continue all summer and into the fall. Also, the individual blooms do not last a long time, so regular deadheading cleans up the plant. It is a little slow to get started in the spring, but once it does, it really grows fast! Also, in colder climates (such as where I live in zone 6), cut the plant all the way back to within about 12 inches of the ground in late winter. It may seem drastic but it really does encourage it to come back bigger and better each year. This is the most fragrant plant on our property.


On Jul 13, 2007, jt0791 from Pembroke, MA wrote:

For those who want to attract butterflies this plant takes the cake by far, Black knights flowers are super sweet and irresistable to butterflies,


On Jun 18, 2007, alddesigns from Saint Cloud, FL wrote:

I've recently gotten 3 different types of butterfly bushes. This one is probably my most favorite. The flowers are such a rich blackberry color and the sweet honey scent is like alyssum, but 10 times sweeter. My plants are still pretty small and already it is flowering. I'm so pleased with it!


On Apr 26, 2007, cjbnc from Raleigh, NC wrote:

In my zone (7ish), this plant doesn't die back in the winter. My mom has one in zone 5 and it does die to the ground every year, but keeps coming back for her. My Black Knight is the most bushy of the Buddlejas in my yard: it has lots of thin stems where the others tend to put out just a few main trunks and branch out from there. As others have said, the smell is wonderful. It reminds me of fresh grape jam.


On Nov 21, 2006, ccjacko1910 from Crescent City, CA wrote:

Purchased this plant the previous spring and planted it next to the steps. Plant grew to 10ft. tall 6ft. diameter. numerous flowers and attractive to birds and bees. This area is on the coast, has fog in the summer and rain in the winter with occasional frost. Summer temp 60 to 70s with occasional 80.Awesome grower but needs to be clipped back to keep within bounds.


On Nov 20, 2006, Marilynbeth from Hebron, KY wrote:

Beautiful! BF's love it!


On Jul 25, 2006, renatelynne from Boerne new zone 30, TX (Zone 8b) wrote:

With our mild winters this plant bloomed all winter and is still blooming into our HOT hot summer. It is planted in full sun next to the road and driveway. I rairly water it.


On Jan 13, 2005, CaptMicha from Brookeville, MD (Zone 7a) wrote:

Black Knight is a very durable, rewarding plant. It requires little care, however, it'll benefit from deadheading the spent blooms.

Butterflies, bees and hummers CANNOT resist this plant. It has an almost overpowering sweet smell. Flower cones are of medium length, not as long as some of the other Buddleja cultivars. It's color is a rich, almost black purple, hence the name, Black Knight.

Plants can be trained to bush out or to grow more upright which lets it fit perfectly into a butterfly garden setting.


On Jul 2, 2004, saya from Heerlen,
Netherlands (Zone 8b) wrote:

Black Knight is blooming for the second year now. The flowers are much bigger now..at least the triple size as last year. I guess the plant has settled now and grew more mature. Black Knight has a wonderfull colour..a very warm and dark purple (you can call it purple black with a red glow in it) with a dark orange eye. I think it is one of the prettiest among the Buddleia. It has a strong honey scent that can fill a room if you put a branch in a vase. I understand now better why butterflies love this bush. If you want butterflies..please plant a Buddlea...I've just counted about 50 butterflies on it!


On Apr 27, 2004, ldygardenermd wrote:

My black knight is prolific in bloom all season long! As long as the flowers are dead headed on a regular basis it maintains it beauty!! I have them planted in a variety of conditions, clay soil with full sun, enriched soil in part sun that stays moist to wet, and part sun in moderate to dry soil. Wonderful plant!!!


On Apr 26, 2004, angelam from melbourne,
Australia wrote:

While I find the plant very drought tolerant. I find the flowers less so. This plant flowers with us in mid-Summer. In dry weather they are often spent in a day and the repeats are very small. I am disappointed in this plant, I have another variety that flowers in Spring and is much more rewarding.


On Jun 1, 2003, lauburt from Vancouver, WA wrote:

Easy to grow and drought tolerant. Wonderful dark purple blooms that are an average of 5 inches long...but some get up to 8 or 9 inches here! Very sweet scent. Nothing beats a buddelia for scent, except maybe a lilac or heliotrope!


On Jul 31, 2002, Abutilon from Coal Center, PA (Zone 6a) wrote:

Well recommended buddliea. Wonderfully fragrant and highly attractive to butterflies.
Easy to bloom and good grown habit.