Oxypetalum Species, Southern Star

Oxypetalumcoeruleum

Family
Apocynaceae (a-pos-ih-NAY-see-ee)
Genus
Oxypetalum (oks-ee-PET-al-um)
Species
coeruleum (ko-er-OO-lee-um)
Synonym
Amblyopetalum coeruleum
Gothofreda coerulea
Tweedia coerulea
Tweedia versicolor
Sun Exposure
Sun to Partial Shade
Foliage
Smooth
Height
12-18 in. (30-45 cm)
18-24 in. (45-60 cm)
24-36 in. (60-90 cm)
36-48 in. (90-120 cm)
Spacing
15-18 in. (38-45 cm)
18-24 in. (45-60 cm)
Hardiness
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)
Bloom Color
Light Blue
Blue-Violet
Bloom Time
Late Spring/Early Summer
Mid Summer
Late Summer/Early Fall
Other Details
Category
Vines and Climbers
Water Requirements
Drought-tolerant; suitable for xeriscaping
Average Water Needs; Water regularly; do not overwater
Foliage Color
Blue-Green
Where to Grow
Bloom Characteristics
Bloom Size
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
Non-patented
Propagation Methods
From softwood cuttings
From seed; direct sow outdoors in fall
From seed; sow indoors before last frost
From seed; direct sow after last frost
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
Regional

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

Arroyo Grande, California

El Cajon, California

Encinitas, California

Fremont, California

Grass Valley, California

Long Beach, California

Los Angeles, California

Napa, California

Sacramento, California

San Diego, California

San Jose, California

Soledad, California

Vista, California(9 reports)

Deland, Florida

Navarre, Florida

Riverview, Florida

West Palm Beach, Florida

Snellville, Georgia

Battle Creek, Michigan

Elizabeth City, North Carolina

Trinity, North Carolina

Fair Play, South Carolina

Okatie, South Carolina

Austin, Texas

Garland, Texas

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Gardener's Notes:

8
positives
1
neutral
0
negative
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J
West Palm Beach, FL | February 2017 | positive

RAIN, SOGGY SOIL and WARM TEMPERATURE is LETHAL FOR TWEEDIA!
Please keep soil on the DRY SIDE (Not too dry either) specially when ...Read More

S
Sacramento, CA | April 2014 | positive

I have this plant in my garden here in Sacramento. This is the second year and it's doing well. We had a few consecutive nights in the 20...Read More

R
(Zone 1) | November 2013 | positive

Southern Star has perhaps more of an upright, trailing or twining habit.

D
Prescott, AZ (Zone 7b) | August 2013 | positive

An Asclepia from South America. "Tweedia" is also called "blue milkweed". This was my first year growing this unusual diminutive plant,...Read More

Z
Z
San Diego, CA (Zone 10b) | April 2011 | positive

This plant has one of the most true blue flowers I've seen. It is a tough plant and very showy in the springtime. In my frost free zone,...Read More

L
L
Battle Creek, MI | September 2008 | positive

This is one of my favorites because the flower is such a beautiful blue. It will grow as an annual in this area, but it is hard to find a...Read More

P
(Zone 8b) | March 2005 | positive

This plant gives beautiful blue flowers during summer and autumn in my climate. It is followed by bizzare, fluffy seedpods. They have a v...Read More

M
El Cajon, CA (Zone 10a) | April 2004 | positive

Abundance of blooms of a very intersting lovely blue color and as a bonus somewhat bizarre seedpods afterwards. Fairly sturdy beautiful p...Read More

T
T
Murfreesboro, TN (Zone 7a) | August 2001 | neutral

Dainty flowers start out as pink buds, opening to lavender or blue. Can be overwintered in a greenhouse, or grown as an annual in colder climates.

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Featured
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