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Cape leadwort

Cape leadwort

Plumbago auriculata
A vigorous, scrambling, semi-climbing tender shrub that flowers almost without pause through the warm months, carrying broad clusters of soft sky-blue (or, in the white form, pure white) phlox-like flowers. Known as the Cape plumbago or Cape leadwort, it is native to South Africa (POWO, Kew) and is grown worldwide as an easy, long-flowering ornamental. The honest catch is its frost-tenderness: it is hardy only in USDA zones 9a-11, so in cold climates it is grown as a conservatory or large-container plant, or treated as a summer annual. Left to its own devices it climbs or sprawls 6 to 10 feet and needs support, or hard pruning, to keep its shape; the flower calyces are sticky and glandular and cling to clothing and animal fur (its own seed-dispersal trick), and it suckers. In return it is one of the best blue-flowered butterfly plants for a warm garden.
Climate fit: narrow (21/100)
Structure
Border
Container
Pollinator
Light
Full sun / Part shade
Water
Moderate water
Mature size
4-10 ft tall · 4 ft apart
Hardy in zones
9a-11
frosty to nearly frost-free winters
Native in Illinois
No
The phlox-like flowers are insect-pollinated and it is a genuine and well-loved butterfly plant - painted lady and red admiral butterflies work the blue blooms for nectar, and honey bees and other insects visit too.

Cold hardiness

These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.
Now
Zone 6b
Plotwright
USDA Zone 6b
-5°F to 0°F
Won't grow here
Zone 7a
Plotwright
0°F to 5°F
Won't grow here
In plain terms: This location has cold winters. Its winters are projected to keep warming through 2050.
Out of range today and still out of range in 2050.

Heat tolerance

Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.
Loading AHS heat-zone data for this location...

Where this plant fits

Suitable across 4 ecoregions - 3 climate-resilient through 2070 · 1 newly possible by 2070. Best matches first.

Plant this, not that

Better fit for this place
For Chicago, IL, these are replacement suggestions: similar plants with a stronger hardiness fit now and/or in 2050.

Similar plants

Browse lateral options with similar roles, light needs, size, or native-range overlap; these are not filtered for a better climate fit.
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Shrub
Full sun / Part sun
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Border
Focal point
Pollinator
Structure
Container
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Border
Pollinator
Structure
Container
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Focal point
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Border
Focal point
Pollinator
Container
Structure
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Kolkwitzia amabilis
Beauty bush
A large, vigorous, fountain-shaped deciduous shrub that earns its common name in late spring, when its arching stems are smothered in masses of pale-pink, yellow-throated, bell-shaped flowers. Native to China, it is one of the great old-fashioned spring shrubs - spectacular in full bloom, much loved by bees, and offering peeling brown bark for quiet winter interest. It is also genuinely big: expect 6 to 10 feet tall and wide at maturity, so give it room rather than fighting its size with the shears. The form to seek out is the Award-winning "Pink Cloud", which carries a clearer, richer pink than the variable seed-grown species.
Shrub
Full sun / Part shade
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Climate: narrow
Focal point
Structure
Border
Pollinator

Educator packet

Plant packet
Cape leadwort educator packet
A vigorous, scrambling, semi-climbing tender shrub that flowers almost without pause through the warm months, carrying broad clusters of soft sky-blue (or, in the white form, pure white) phlox-like flowers. Known as the Cape plumbago or Cape leadwort, it is native to South Africa (POWO, Kew) and is grown worldwide as an easy, long-flowering ornamental. The honest catch is its frost-tenderness: it is hardy only in USDA zones 9a-11, so in cold climates it is grown as a conservatory or large-container plant, or treated as a summer annual. Left to its own devices it climbs or sprawls 6 to 10 feet and needs support, or hard pruning, to keep its shape; the flower calyces are sticky and glandular and cling to clothing and animal fur (its own seed-dispersal trick), and it suckers. In return it is one of the best blue-flowered butterfly plants for a warm garden.
Scientific name
Plumbago auriculata
Plant type
shrub
Hardiness
9a-11
Light
full-sun, part-shade
Moisture
moderate
Spacing
48 inches
Classroom prompts
- Which plant traits are observations, and which are care recommendations?
- How would this plant fit change if the garden location moved warmer, colder, wetter, or drier?
- Which source-backed facts would you cite in a lesson handout?
Use the Sources & citations section below for page citation styles and the field-level source list.

Sources & citations

Cite this page
For lesson plans, articles, or research that uses this page. Use the source cards below to explore the references that informed this record.
Plotwright. (2026, May 17). Cape leadwort (Plumbago auriculata). Retrieved 2026, August 20, from https://plotwright.com/plants/plumbago-auriculata
Sources used for this record
This record is compiled from the sources below.
Plants of the World Online (POWO)
Botanical research database
RHS Find a Plant
Botanical research database
GBIF
Botanical research database
Wikipedia (ecoregion articles)
Botanical research database
Wikimedia Commons
Photo