Morning Glory 'Heavenly Blue (Clarke's Extra Early Strain)'

Ipomoea tricolor

Family: Convolvulaceae (kon-volv-yoo-LAY-see-ee) (Info)
Genus: Ipomoea (ip-oh-MEE-a) (Info)
Species: tricolor (TRY-kull-lur) (Info)
Cultivar: Heavenly Blue (Clarke's Extra Early Strain)
Hybridized by Denholm Seed Company
Registered or introduced: 1936


Vines and Climbers

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Full Sun

Sun to Partial Shade

Light Shade



Foliage Color:

Unknown - Tell us


15-20 ft. (4.7-6 m)


24-36 in. (60-90 cm)


USDA Zone 11: above 4.5 C (40 F)

Where to Grow:

Can be grown as an annual


Seed is poisonous if ingested

Parts of plant are poisonous if ingested

Bloom Color:

Light Blue

Dark Blue

Bloom Characteristics:

Unknown - Tell us

Bloom Size:

Unknown - Tell us

Bloom Time:

Late Summer/Early Fall

Other details:

Unknown - Tell us

Soil pH requirements:

6.6 to 7.5 (neutral)

Patent Information:


Propagation Methods:

From seed; sow indoors before last frost

From seed; germinate in a damp paper towel

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:

Sun City, California

Gardeners' Notes:


On Jul 3, 2012, skydog1 from Leeds,
United Kingdom wrote:

Have seen this plant growing extravagantly wild all over E Turkey and am going to try to grow some from seed next April in our 'cactus garden to trail along the border wall. Not the usual 'bindweed' that we are always pulling out of the borders here in England!


On Sep 20, 2009, RON_CONVOLVULACEAE from Netcong, NJ (Zone 5b) wrote:

Clarkes early blooming strain of Ipomoea tricolor was noticed by Mr.Clarke on his property and he had the seeds multiplied by some companies and since there were no patents on the plants some of the companies started to market the early blooming strain and it may be that some companies are claiming to have 'hybridized' what Mr.Clarke noticed growing on his property.

Member QueenB had discovered a very light colored Heavenly Blue which has been mistakenly stated to be Clarke's and sometimes passed off as 'summer skies'


On Sep 19, 2009, Rareseedman from Birmingham,
United Kingdom wrote:

Few people realise that 'Clarke Extra Early Strain" was introduced in 1936. The usual forms of "Heavenly Blue" were quite late flowering

The usual "darker" ipomoea tricolor these days called "Heavenly Blue" has little resemblance to the true "Clarkes Extra Early Strain" that has larger flowers, more vigour and is profuse in every manner, rather than flowering in about 120 days from sowing it flowers in about 85 to 90 days.

Often you will see the packet's marked "Heavenly Blue" and you expect the true azure powder blue...but you never get it as often the photos are recycled or the product inside does not match the photo which is usual for morning glories.

Here is "Clarke's Extra Early Strain" Also notice it is DIFFERENT than other ipomoea tricolo... read more