Euphorbia Heterophylla is an erect herbaceous plant about 30-100 cm tall. The stem can be branched or angular and cylindrical with nodes.
It is easily recognizable by its smooth green leaves and the milky latex it produces when many parts of the plant are broken. The sap can cause eye and skin irritation or serious complications like anaphylaxis.
Euphorbia Heterophylla Classification
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Euphorbiales
- Family: Euphorbiaceae
- Genus: Euphorbia
- Species: Euphorbia heterophylla
- Varieties: Euphorbia heterophylla var. cyathophora
- Common Names: Desert poinsettia, Wild poinsettia, Red milkweed, Painted leaf spurge, Painted spurge, Catalina, Fire on the Mountain, and Summer Poinsettia.
Nativity and Distribution
Milkweed is native to tropical and subtropical regions in the Americas. It has since been introduced to other areas including Africa, Asia, and the Pacific.
It can be found in places like:
- Southern United States
- Mexico
- The Caribbean
- Brazil and other parts of South America
- India
- Thailand
- Kenya
- Ghana
Physical Characteristics
- Leaves: Small and lanceolate upper leaves and broad and ovate upper leaves.
- Fruits: Small 3-lobed yellowish-green fruits.
- Stems: Herbaceous. It can grow up to 1m in height.
- Flowers: Yellow-green clusters of scythia
- Roots: Tap root system.
Euphorbia heterophylla is an annual herbaceous plant that can grow up to 1m in height. It is easily recognizable by its smooth green leaves and the white sap it produces when the stems or leaves are broken.
The stem is upright and hollow about 3-8mm wide and reddish-green in color. When damaged or broken it exudes abundant white milky latex that can cause eye irritation and conditions like dermatitis and anaphylaxis.
As a plant that exhibits heterophylly — the Mexican Fireplant develops different leaf shapes and sizes, hence the name “heterophylla” which means different leaves. The lower leaves are broad and alternate with a more pronounced serrated margin and bright green color. The upper leaves are narrow and opposite with a yellowish-red tinge and smoother margin.
Milkweed produces cyathia, consisting of cup-like inconspicuous flowers (with a few stamens and a single pistil), surrounded by colorful bracts that can be bright green, yellow, or red.
The seeds are oblong to obovate, grayish to black, and about 2.5-3mm wide and 2.5mm long.
Reproduction, Dispersal, and Life Cycle
- Life Cycle: Annual.
- Seeds: A single plant can produce 4,500 seeds in a single season.
- Climate: Grows well in the tropical and subtropical climates.
- Dispersal: Self-dispersal, water, vehicles, animals, and contaminated agricultural produce.
Euphorbia heterophylla behaves as an annual plant. A single plant produces 100 seeds at a given time and 4,500 seeds in one growing season.
With the right conditions, seeds that land on the surface and up to 10 cm below the ground surface germinate easily. The seeds buried deep in the soil remain viable for many years because they do not depend on sunlight for germination.
The seeds are mainly spread through explosive dispersal. When the fruits mature, the capsules explode, shooting the seeds a distance from the parent plant for dispersal.
The milkweed seeds can also be dispersed by water, animals, on mud found on vehicles, and as a contaminant in agricultural produce.
Similar Plants
- Euphorbia cyathophora
- Euphorbia pulcherrima
Uses
- The leaves and stems are used to formulate traditional medicines for skin problems, bronchitis, asthma, and gastrointestinal disorders.
- It is an important research plant subject for the treatment of cognitive disorders like Alzheimer’s.
- It is used as an ornamental in landscapes and gardens for its colorful bracts.
Impact on Farms and Environment
Milkweed is considered a problematic farmland weed because of its rapid growth and competition for essential nutrients and water in the early crop growth stages.
It is particularly a major problem in coffee, cotton, cowpeas, sorghum, sugarcane, soybean, maize, and tea farms. Studies have shown 30%-50% crop yield losses where milkweed grows alongside valuable plants like soybeans and groundnuts.
Apart from reduced yields, heavy milkweed infestations can also slow down harvesting and reduce harvest crop quality by contaminating it with its sticky latex sap.
Its rapid growth and adaptability to different environments allow the weed to colonize new areas quickly, outcompeting native vegetation and negatively affecting biodiversity.
Control
Chemical control: 2,4-D, bromacil, ametryn, imazaquin, chlorimuron-methyl, ammonium glufosinate, metribuzin, terbacil, and paraquat.
It is not easy to control Euphorbia heterophylla with chemical herbicides as it tends to develop resistance over time. The herbicides listed above provide reasonable to adequate control.
Herbicide combinations and repeat treatments may be required for more satisfactory results.
Visit the CABI compendium for more information on the herbicide combinations you can use on your farm or landscape. You can also consult with a local professional for more effective milkweed control.
Lead Editor for Insight Weeds.