L. grandiflora is an emergent, aquatic, herbaceous perennial with two growth forms. During the first growth stage, the plant produces smooth or sparsely pubescent stems that grow horizontally over the soil or water, rooting at nodes and producing white, spongy roots. Leaves are smooth, alternate and have petioles. During the second stage, shoots begin to grow vertically and flower, stems become pubescent and can grow up to 1 m tall (USACE-ERDC, 2009). Leaves tend to be more elongate in the second growth form (IPAMS, 2009), but can vary widely in shape from lanceolate to elliptic and acute at both ends (USACE-ERDC, 2009). Flowers are on solitary stalks that are approximately 2.5 cm long;actinomorphic;sepals 5 (rarely 6), villous or glabrous;petals 5, caducous, obovate, emarginate, bright golden-yellow with a darker spot at the base;stamens in 2 whorls, the epipetalous ones shorter;disc slightly elevated, with a depressed, white-hairy nectary surrounding the base of each epipetalous stamen;style glabrous or hairy in lower two-third. Fruit is a pubescent light-brown capsule, 2.5 cm long containing 40-50 seeds, 1.5 mm long, embedded in a woody endocarp (IPAMS, 2009).
Related invasive species
- Ludwigia grandiflora
Related Farm Practice
- Soil
- Light
- Rooting
L. grandiflora is a productive emergent perennial native to South and Central America and parts of the USA. It was introduced to France in 1830 and has become one of the most damaging invasive plants in that country (Dandelot et al., 2008). It was more recently introduced beyond its native range in the USA, where it also causes severe problems (IPAMS, 2009). In its adventive range, L. grandiflora can transform ecosystems both physically and chemically. It can sometimes be found growing in impenetrable mats;under these conditions, L. grandiflora can displace native flora and interfere with flood control and drainage systems, clog waterways and impact navigation and recreation (IPAMS, 2009). The plant also has allelopathic activity that can lead to dissolved oxygen crashes and the accumulation of sulphide and phosphate in the water. These not insubstantial and year-round effects on water quality can cause ‘dystrophic crises’ and intoxicated ecosystems (Dandelot et al., 2005).
Impacts on the local environment by L. grandiflora can be severe. The species possesses an allelopathic activity that changes water quality throughout the year and can lead to impoverished flora by decreasing seedling survival of vulnerable native taxa (Dandelot et al., 2008). L. grandiflora has been shown to cause severe hypoxia or even anoxia during summer months as well as leading to reduced sulphate and nitrate levels and increased sulphide and phosphate concentrations, leading to what Dandelot et al. (2005) refer to as ‘a dystrophic crisis’ and an intoxicated ecosystem.