Argemone Plant Growing & Care Guide for Gardeners

Article by Dean Ravenscroft, Ph.D. - Updated 21st Nov 2023

In this Gardener's HQ guide, we'll explore cultivating Argemone plants in your garden, indoor spaces, and other settings.

Mexican Poppy, and Prickly Poppy: Cultivation & Garden Use

The common names for the short-lived perennial Argemone include the Mexican poppy and Prickly poppy.

Although this genus of plants is a perennial they are typically grown as a hardy annual by gardeners.

Argemone poppies typically flower in the summer in the wild, but can flower over a much longer period when grown in gardens.

Argemone mexicana by dinesh_valke.

Description of Mexican poppy - Argemone

Argemone species such as Mexican poppies have a continuous display of yellow, white or red poppy like flowers, which are very fragrant, from late summer to early autumn.

They are best grown in the mid section of borders as they have a very spiky foliage.

Argemone pleiacantha by Botanista.

Argemone and its Commonly Grown Garden Species

Members of the Argemone genus are native to America, and are known to grow wild in the Eastern parts of Canada and in all of the US states except for Alaska.

The genus contains approximately 30 members and is a member of the Papaveraceae family of plants (better known as the poppy family).

One of the features that this family is known for is the presence of laticefer ducts that produce a latex juice.

Argemone members tend to have prickly leaves of approximately 3 to 6 inches (9 to 15 cm) in length and small yellow or white flowers. Seeds, such as those from the Mexican prickly poppy have a pale yellow latex that is often used as a sedative in medicine.

As a member of the Papaveraceae family Argemone is closely related to Poppy (Papaver), Blood root (Sanguinaria), Plume Poppy (Macleaya) and Bush Poppy (Dendromecon).

Some of the commonly seen members of the Argemone genus include:
Argemone mexicana (Cardosanto; Mexican poppy; Mexican prickly poppy).
Argemone corymbosa (Mojave prickly poppy).
Argemone pleiacantha (Prickly poppy).
Argemone aenea (Golden prickly poppy.
Argemone sanguinea (Red Prickly poppy).
Argemone glauca (Smooth prickly poppy).
Argemone polyanthemos (Crested prickly poppy).

How to Grow Argemone

It is best to sow Argemone poppy seeds just below the soil surface at a depth of about 3 mm in the late spring after the last frost.

It is quite difficult to propagate Argemone species inside. If doing so then seeds should be planted in peat pots around five to seven weeks before they are due to be put out (after the last frost of early Spring).

They should be grown at 13 to 16 degrees Celsius, and normally take about two weeks to germinate.

When planting out they should be placed in an area that receives lots of sunshine and planted at a distance of around 25 cm for smaller Argemone species, and 75 to 90 cm for larger varieties.

How to Care for Argemone

Mexican prickly poppies and other Argemone members are easy to look after, however they are easily damaged so they should neither be staked nor transplanted (unless absolutely necessary).

The poppies should be dead headed before seed is allowed to set in order to eliminate the plant spreading uncontrollably.

Specific Species Information for Growing Argemone plants

Argemone mexicana (Yellow prickly poppy; Mexican Prickly Poppy; Cardosanto)

This plant is grown as an annual in the garden seeds should be scattered in the spring and lightly dusted with soil for a wild effect or space out at about 6 to 10 inches (15 to 25cm) in a full sunlight region of the garden; do not attempt to transplant them once growing.

Plants reach from 24 to 36 inches (60 to 90cm) in height. Leaves of this species are prickly (wear garden gloves when handling), plants bloom with 5 cm (2 inch) yellow or golden flowers from mid summer through to early autumn.

As a native to Mexico and the southern states of the USA these plants are quite drought tolerant, and grows well in zones 8 to 11.

It is important to deadhead the pant to prevent them from spreading wildly.

Argemone pleiacantha (Prickly Poppy)

These plants reach a height of about 36 inches (90 cm) and carry blue prickly leaves; take care when handling them, preferably use gloves. They should be sown at a space of about 15 inches (38 cm) at a depth of 1/8th of an inch (3 mm) in a sunny part of the garden.

Ideally the soil should be pH 6 to 8. The plant blooms in Summer with large white flowers with yellow centers.

Plants are drought tolerant and require dead heading to prevent them growing wildly.

Best suited to growing in the hot southern states such as Arizona, Florida and New Mexico.

Common Questions

How many members does the Argemone genus have?

The Argemone genus, commonly known as prickly poppy, includes about 30 species of flowering plants.

Do members of Argemone make a good garden or landscaping plant?

Argemone can be a dramatic addition to a garden with its large, poppy-like flowers and spiky foliage, though its prickly nature may not suit all settings.

Which Argemone species are most frequently grown by gardeners?

The most frequently grown species is Argemone mexicana, or Mexican prickly poppy, known for its bright yellow flowers.

Are members of the Argemone plant genus fragrant?

Argemone flowers are not generally noted for their fragrance.

What is the perfect location to grow Argemone?

Argemone prefers full sun and well-drained soil. It is tolerant of poor, dry soils and is often found in desert or coastal environments.

Is Argemone invasive in the USA, if so in which states?

Argemone is not typically considered invasive in the USA, though it can self-seed readily in the right conditions.

How do I remove Argemone plants from my garden?

To remove Argemone, wear gloves to protect from prickles, and pull or dig out the plants, ensuring to remove the entire root system.

Summary

The Argemone genus, also known as prickly poppy, is part of the Papaveraceae family and includes about 32 species of annual and perennial plants. Native to the Americas, these plants are known for their showy, poppy-like flowers and spiny, bluish-green foliage. They are most often found in arid regions, on disturbed soils, and along roadsides.

Prickly poppies prefer full sun and well-drained soil. They are highly drought-tolerant, making them a good choice for xeriscaping and for gardens in arid climates. Despite their attractive flowers, their spiny stems can make them less desirable for some garden settings. Care should be taken as all parts of these plants are toxic if ingested.

I hope that you enjoyed this guide on Argemone. You may also enjoy the following Gardener's HQ growing guides: How to grow Matilija Poppy and Meconopsis plants.