Argemone

( ar - JEM - on - ee )

At-A-Glance Information

Commonly known under the name Prickly Poppy, this genus contains species of annuals and biennials that need partial to full shade and regular water to perform well in the landscape. Individual plants grow to reach 3 feet tall and 1.5 feet wide at maturity, with showy white or yellow poppy flowers that bloom in summertime. Prickly Poppy will reseed and colonize as plants fade and return each year. Species are native to Hawaii and the Americas. Take care when planting these interesting flowers in your garden, as all plant parts are poisonous to humans, pets, and other animals if ingested.

argemone Species and Varietals

The genus Argemone is a member of the plant family Papaveraceae and includes 32 species. Argemone growing zones vary depending on the species; for more information, see the species descriptions below. To find your zone, click here: Zone Map.

Argemone albiflora (White Prickly Poppy, Bluestem Prickly Poppy, Texas Prickly Poppy, Carolina-Poppy)
This species is native to the Midwest United States where it grows in sandy and gravelly soils and produces white flowers. Foliage has sharp spines. The oil derived from this species' seeds was used during WWII as a fine lubricant. The oil content of the seeds is 25.8, close to that of soybeans. These flowers grow well in USDA hardiness zones 7-9. Considered weedy and somewhat invasive outside of its native range.

Argemone corymbosa (Mojave Prickly Poppy)
This species is native to the Mojave Desert in the United States, and grows on sandy plains and dry slopes in its native range. It is especially common around Cima and Kelso communities in California. The stems of this plant are covered in an orange latex material. Individual plants reach up to between 16 and 32 inches tall when mature and in bloom. These plants grow well in USDA hardiness zones 7-10.

Argemone glauca (Hawaiian Poppy, Pua Kala, Naule, Pokalakala, Kala, Thorny Flower)
This native of Hawaii is commonly found in rocky or sandy disturbed soils. It can be found growing on all of the main land masses in the island chain, and produces white flowers with yellow centers. Foliage is blue-grey-green with a waxy tint, and the latex sap within stems is yellow. This is a perfect plant for xeric landscaping and grows well in USDA hardiness zones 10a-11b.

Argemone mexicana (Mexican Poppy, Flowering Thistle, Cardo, Cardosanto, Mexican Thistle, Satyanashi, Siyal-Kanta)
This annual does best in USDA hardiness zones 8-11 or Sunset growing zones 2, 3, 7-24, H1 and H2. This species of Prickly Poppy is native to the West Indies, Central America and Florida, and has yellow to orange flowers. Variety 'Yellow Lustre' has lemon-orange blooms and blue-green variegated leaves. These plants are considered highly invasive outside of their native range, especially in agricultural land.

Argemone munita (Flatbud Prickly Poppy, Chicalote)
Chicalote is a California native plant with blue-green or mint-green foliage. Flowers are white with yellow centers. Plants produce erect, spiny stems and foliage, and reach between 3.5 and 5 feet tall when mature. In bloom towards the end of summertime. These flowers do well in USDA hardiness zones 5a-10b. Considered a troublesome weed and/or invasive in disturbed soils outside of its native range.

Argemone ochroleuca (Pale Mexican Prickly Poppy, Mexican Poppy)
This native of Mexico has been identified as a weed in many areas of the globe, and reaches about 3 feet 3 inches tall when fully grown. Plants exude a sticky yellow sap when cut. These plants have a high invasive potential, outcompeting native species and decreasing biodiversity outside of its home range.

Argemone pinnatisecta (Sacramento Prickly Poppy)
With white flowers that bloom between the months of May and August, this rare and endangered species is native to New Mexico, where it grows on the slopes and bottoms of canyons. Individual plants reach up to 5 feet tall when mature and in bloom. Foliage is deeply divided and blue-grey. Stems and leaves are very thorny.

Argemone polyanthemos (Argemone intermedia) (Bluestem Prickly Poppy, Annual Pricklypoppy, Thistle Poppy, Crested Pricklypoppy, White Pricklypoppy)
This annual or biennial grows in zones 2, 3, and 7-24. This is a western native with shabby-chic style white flowers with yellow centers. Native to the southwestern United States through to some areas of the Pacific Northwest. This species is considered invasive west of its native range in the central United States.

Caring for ARgemone

Take care when planting these interesting flowers in your garden, as all plant parts are poisonous to humans, pets, and other animals if ingested. Some species are also considered invasive outside of their native range; make sure to check with local authorities before planting. Argemone, or Prickly Poppy, plants have long taproots that delve deep into the soil profile in search of nutrients and moisture. While this makes them drought-tolerant and easy to care for, it also makes them quite difficult to transplant successfully. If you are transplanting a nursery specimen, take great care in not disturbing its established root system inside the pot when planting. Prickly Poppy plants can easily be started from seed, as well, and will reseed freely in the landscape when left to their own devices. Plant Prickly Poppies in full sun (ensure that they will receive between 6 and 8 hours of sun each day), and before planting, ensure that soil is well-draining. These plants prefer sandy or loamy soil with a pH of between 6.0 and 8.0 (neutral to slightly acidic). Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants are considered drought-tolerant, able to get by on rainwater alone for much of the year with supplemental irrigations during extended periods of drought.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Prune to maintain an attractive shape and size. To encourage bushier growth, especially when the plant is young, pinch back branch tips. These plants naturally form an attractive but loose bushy structure, with long stems and copious flowering heads. Remove dead or damaged branches, as well as any that cross. Deadheading regularly can encourage many new blooms to pop, and will also discourage the invasive or weedy nature of these plants from becoming a problem. Many Argemone species are annuals, lasting for just one year in the garden, but they can also be grown as short-lived perennials in their native zones. Overall, they are considered ephemeral ornamentals, but will re-seed freely in the garden, providing blooms for years to come.

Propagation

Prickly Poppy plants are best propagated via seed; they have a large taproot that makes them difficult to transplant. For best results, direct-sow seed in fall. To propagate your Prickly Poppy, follow the instructions below:

Propagating Argemone by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, soil, and a pair of shears.
Harvest your seeds. The seed pods are pretty easy to spot, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant with clean, sharp shears, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. The pods will continue to split open and release the seeds contained inside. Once they have all been released, take them out of the bag and put them in a container so you can work with them or place them in a storage container until you are ready to sow. These seeds can last for several years in storage and still retain viability.
In fall, broadcast seed and work it into the soil a few inches down. Water regularly. Sprouts should emerge within 2-6 weeks.