The bleeding heart tree, Homalanthus populifolius, is a weed common in Australia’s rainforests. Its leaves turn red as they age.
The plant is a fast-growing species that colonizes any open ground, whether a forest opening, disturbed edges, or roadsides.
The bleeding heart tree lives for about ten years. Its seeds have a long dormancy period and are dispersed by birds when ready.
Scientific Classification
- Kingdom: Plantae
- Phylum: Tracheophyta
- Class: Magnoliopsida
- Order: Malpighiales
- Family: Euphorbiaceae
- Genus: Homalanthus
- Species: Homalanthus populifolius
- Other Names: Queensland poplar, Bleeding heart tree, Umbrella tree, Native poplar, Euphorbia populneus, Omalanthus populifolius
Nativity and Distribution
The bleeding heart tree is native to New Guinea and the Pacific Islands. This plant is also considered a serious weed in:
- New Zealand
- Western Australia
- Hawaii
- Sri Lanka
- South Africa
Physical Description
- Leaves: Heart-shaped leaves 3-15cm long and 3-12cm wide.
- Flowers: Tiny yellow to green flowers 60-100 mm long.
- Fruit: Green two-lobed capsule up to 10mm long.
- Stem: Has a smooth trunk that is brown or pale grey.
- Roots: Rhizomous roots.
Homalanthus populifolius leaves are simple and alternate. The plant’s green leaves turn to shades of purple or red throughout the year as they age.
The plant has dark, fleshy, two-lobed capsular fruits that get ripe in summer and have an explosive cover. The fruit foliage is dark and green in color.
Life Cycle/Reproduction/Dispersal
- Life Cycle: Perennial.
- Seeds: The plant’s seeds have a fleshy aril.
- Climate: The plant is adapted to environments with high humidity and consistent moisture.
- Dispersal: Seeds are dispersed by birds, water, and gravity.
The bleeding heart tree is dioecious, meaning the plant has separate female and male plants.
The plant reproduces sexually through its fruits, which produce seeds dispersed by water, gravity, and birds.
Favored germination conditions for the plant include high light levels and moisture-holding capacity in the soil. The plant’s ideal growing temperature is between 55 and 75 degrees Fahrenheit.
Homalanthus populifolius may mature between 18 and 24 months. In open conditions, it can develop into small trees, reaching a height of 5 to 7 meters, while some trees even top 10 meters in lowland forests.
Uses
- Source of food for native birds, particularly the brown cuckoo dove, silvereye, and Lewin’s honeyeater, which readily spreads its seed.
- Used to make dyes. The plant’s bark and leaves can make a black dye that can stain baskets and other rattan and Corypha palm-made objects.
Impact on Environment
The bleeding heart tree is an invasive species that outcompetes native plants. It produces prolific seeds that are easily dispersed by birds, water, and gravity, facilitating its dispersal to new areas.
The plant’s leaves are poisonous to cattle, and its latex causes skin infestations.
Control
The following control methods can be used for Homalanthus populifolius:
- Hand-pulling the plant’s seedlings
The most effective control method for small infestations is pulling or digging out the plant’s seedlings from the roots. This should be done when the ground is relatively moist.
- Cut stump treatment
Cut stump herbicide treatment can control invasive woody plants like bleeding heart trees.
Apply picloram gel directly to the cut stump. The herbicide kills the stump to prevent new growth that would normally occur if the stump alone had been cut.
- Metsulfuron methyl
Homalanthus populifolius can be sprayed with metsulfuron-methyl. Plant foliage and roots absorb the systemic pesticide, which inhibits an enzyme necessary for plant growth, resulting in chlorosis and necrosis.
However, it’s recommended to spray metsulfuron-methyl before the plant becomes mature and woody.
Lead Editor for Insight Weeds.