🌿 Morphology
🌞 Growing conditions
🌍 Origin and family
🌾 Uses
Warning: Despite the care taken in writing this sheet, it is essential to cross-reference sources before using or consuming any plant. When in doubt, consult a qualified professional
Permaculture uses
While considered a weed by many, giant ragweed seeds are edible and contain oil. The plant can be used as a chop-and-drop mulch or compost to add biomass to the soil. It can also be used as a pioneer species to establish vegetation on disturbed land, providing shade and suppressing other weeds before more desirable plants are introduced. Some studies suggest allelopathic properties, potentially suppressing the growth of neighboring plants.
Permapeople description
A robust annual plant known for its allergenic pollen and significant size.
Botanical description
Ambrosia trifida, commonly known as giant ragweed, is an annual plant in the Asteraceae family. It is native to North America and can grow to impressive heights, often reaching 6 to 15 feet tall, or even up to 20 feet under optimal conditions. The stems are stout, hairy, and branching. The leaves are large, typically three-lobed (trifida meaning 'divided into three'), but can also be unlobed or have five lobes. The plant is monoecious, meaning it has separate male and female flowers on the same plant. The male flowers are small and greenish, borne in long, terminal spikes, releasing copious amounts of pollen. The female flowers are found in clusters at the base of the male spikes or in the leaf axils. The fruit is a single-seeded achene enclosed within a bur-like involucre.
Companion planting
Due to its allelopathic properties and rapid growth, giant ragweed is generally considered an undesirable companion plant. It can outcompete other plants for resources and potentially inhibit their growth. It is not generally recommended for intercropping or companion planting strategies.
Propagation methods
Giant ragweed primarily propagates by seed. Seeds can be directly sown in the fall or spring. The plant can self-seed readily, often becoming a nuisance in agricultural fields and disturbed areas. Seedlings transplant poorly due to a deep taproot.
History and traditions
Native Americans traditionally used giant ragweed for various medicinal purposes. Some tribes used the plant to treat skin ailments, digestive issues, and fevers. The seeds were occasionally used as a food source, though their small size made them less desirable than other grains. Due to its prolific pollen production, it's also historically known for causing hay fever.
Usage calendar
Seeds germinate in spring (April-June). Flowering occurs in late summer to fall (July-October). Seed maturation and dispersal occur in fall (September-November). Pruning or removal is best done before seed set to prevent further spread.