Ipomoea, Tall Morning Glory 'Kniola's Black'

Ipomoea purpurea

Family: Convolvulaceae (kon-volv-yoo-LAY-see-ee) (Info)
Genus: Ipomoea (ip-oh-MEE-a) (Info)
Species: purpurea (pur-PUR-ee-uh) (Info)
Cultivar: Kniola's Black
Synonym:Convolvulus purpureus
Synonym:Ipomoea hirsutula
Synonym:Ipomoea purpurea var. diversifolia
Synonym:Pharbitis purpurea



Vines and Climbers

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Sun to Partial Shade

Light Shade




Foliage Color:

Unknown - Tell us


12-15 ft. (3.6-4.7 m)

15-20 ft. (4.7-6 m)

20-30 ft. (6-9 m)


15-18 in. (38-45 cm)


Not Applicable

Where to Grow:

Unknown - Tell us


Parts of plant are poisonous if ingested

Bloom Color:

Dark Purple/Black

Bloom Characteristics:

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

Bloom Size:

Unknown - Tell us

Bloom Time:

Mid Summer

Late Summer/Early Fall

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:

Unknown - Tell us

Propagation Methods:

From seed; stratify if sowing indoors

From seed; sow indoors before last frost

From seed; direct sow after last frost

From seed; germinate in a damp paper towel

Scarify seed before sowing

Self-sows freely; deadhead if you do not want volunteer seedlings next season

Seed Collecting:

Allow pods to dry on plant; break open to collect seeds

Properly cleaned, seed can be successfully stored


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

Tuskegee, Alabama

Carmichael, California

El Sobrante, California

Elk Grove, California

Richmond, California

Centerbrook, Connecticut

Smyrna, Delaware

Zephyrhills, Florida

Dunmor, Kentucky

Fitchburg, Massachusetts

Allen Park, Michigan

Bay City, Michigan

Lafayette, Tennessee

Thompsons Station, Tennessee

Brazoria, Texas

Jacksonville, Texas

Plano, Texas

Spring Branch, Texas

Vancouver, Washington

Madison, Wisconsin

show all

Gardeners' Notes:


On Jul 6, 2012, Prunerman from Middleton, MA wrote:

Just bought and planted this Kniola in my garden against bunny ears plants for a contrasting light colored background. It will (hopefully) climb up a freestanding wrought iron trellis.
In a month or so, I'll post a progress note.


On Jul 10, 2010, Q734 from Allen Park, MI wrote:

A couple of years ago I ran across Kniola blacks online and ordered some.

As they went to seed I saved them carefully as the flowers are a beautiful deep dark velvety purple, and yes, almost black, but fabulously so. They're a deeper darker purple than a Grandpa Ott and without the pink throat.

Fast forward a couple years and I'm yanking them out as they would aggressively compete with and will hybridize HBs, thoroughly dominating HBs, plus they're a smaller bloom than a good heavenly.

So now when I see a determined Kniola, which have a fuzzy stem as opposed to the smooth one on a Heavenly, I yank, yank, yank.

They are a sure thing tho, and very strong. Funny I never would have imagined me pulling these out! But if I wanted the ... read more


On Nov 13, 2009, dixielol from Dunmor, KY (Zone 6a) wrote:

I've had a hard time getting this plant to "climb" on its own & resorted to tieing it up with string. In my opinion, the flowers are well worth the trouble of tieing it up. Had a lot of compliments on it. It also gave me alot of seeds!


On Aug 31, 2008, gardenbugde from Smyrna, DE (Zone 7a) wrote:

This is my first year for Kniola's Black Knight. It was started indoors in peat cups and transplanted in May. It has grown well, although the vines are not as thick as other cultivars. The color is lovely though and will probably use them as part of a "mix" next year. Seeds mature quickly too.


On Mar 14, 2008, rebecca101 from Madison, WI (Zone 5a) wrote:

This morning glory starts blooming earlier than others, while it is still vining (early July for me). The flowers are a very dark purple color. Flowers were mostly hidden by the leaves. They did not flower very profusely, and in general did not make a very good garden display. The vine is very vigorous and gets huge and heavy - it toppled the trellis it was on by mid-summer (8 ft. tall teepee made of four very thick posts sunk deep into the ground!). I direct seeded into the garden in May, and the seeds did not germinate that year but the next year instead - they may need vernalization or winter sowing.


On Jul 29, 2004, Marshmellow from Fitchburg, MA wrote:

Alright, I'd like to know who came up with this color scheme to a wonderful vine, they should be fired.

I got a package of "Random vines" and this is the dominant type that's growing. I can see why it's the dominant type after seeing it bloom. They must get a deal of the seeds of the types that don't sell and put them in the random vine package, after seeing this variety I can see why it doesn't sell. Listen people, it's dark, very dark, so dark that in the shade it blends in and you don't notice the flower... and in the sun it's so dark it absorbs the light and you can't notice the flower. Either way, you don't notice the flower! The pictures tell it all, it's not a stop people walking by to see the flowers because no one's going to notice them. It's to the point I... read more


On Jun 26, 2003, michael10 wrote:

Very beutiful flower! In my opinion the correct name should be: Knowlian´s black