A monocotyledonous, herbaceous perennial, the plant is native to eastern North America, from northern Quebec to the southern parts of the United States through the Appalachian Mountains into northernmost Georgia and west to Minnesota.

It is easily recognized by its attractive three-petalled white flowers, opening from late spring to early summer, that rise above a whorl of three leaf-like bracts.

The G. Richard Thompson Wildlife Management Area in the Blue Ridge Mountains is renowned for an extensive stand of white trillium that blooms each spring.

Over a two square mile area along the Appalachian Trail near Linden, Virginia there is a spectacular annual display of white trilliums estimated at near ten million individuals.

[4] Trillium grandiflorum is a perennial that grows from a short rhizome and produces a single, showy white flower atop a whorl of three leaves.

[8] The erect, odorless flowers are large, especially compared to other species of Trillium, with 4 to 7 cm (1.5 to 3 in) long petals, depending on age and vigor.

Between the veined petals, three acuminate (ending with a long point) sepals are visible; they are usually a paler shade of green than the leaves, and are sometimes streaked with maroon.

The styles are white and very short compared to the 9–27 mm (0.35–1.06 in) anthers, which are pale yellow, but become a brighter shade when liberating pollen due to the latter's color.

Many of these forms have been given taxonomic names with epithets such as albomarginatum ("white-margined", referring to the petals), foliaceum, ("leaf-like, leafy"), giganteum ("unusually large or tall"), and longipetiolatum ("with long petioles").

[27] Trillium grandiflorum favors well-drained, neutral to slightly acid soils, usually in second- or young-growth forests.

The seeds are dispersed in late summer, germinating after a cold and then a warm period, producing a root and after another winter the seedling's cotyledon emerges from the soil.

Because growth is very slow in nature, T. grandiflorum typically requires seven to ten years in optimal conditions to reach flowering size, which corresponds to a minimum of 36 cm2 (5.6 sq in) of leaf surface area and 2.5 cm3 (0.15 cu in) of rhizome volume.

[32] Trillium grandiflorum has long been thought to self-pollinate based on the fact that pollinators had rarely been observed visiting the plants and because there is low variation in chromosomal banding patterns.

This has been strongly challenged, as other studies have shown high pollination rates by bumblebees and very low success of self-pollination in controlled experiments, implying that they are in fact self-incompatible.

Insect dispersal is aided by the presence of a conspicuous elaiosome, an oil-rich body attached to the seed, which is high in both lipids and oleic acid.

This helps to explain post-agricultural colonization of forest sites by Trillium grandiflorum, as well as long distance gene flow which has been detected in other studies.

Furthermore, it helps resolve what has been called "Reid's paradox", which states that migration during glaciation events must have been impossible for plants with dispersal rates under several hundred meters (yards) per year, such as Trillium grandiflorum.

[35] Furthermore, nested clade analysis of cpDNA haplotypes has shown that Trillium grandiflorum is likely to have persisted through the last glacial period in two sites of refuge in the southeastern United States and that long distance dispersal was responsible for the post-glacial recolonization of northern areas.

This is particularly important for young plants because their small rhizomes, with few & short roots, are easily dislodged (e.g. frost heaveal and other erosion factors) and desiccated.

[39][40] When foraging intensity increases, individuals become shorter each growing season due to the reduction in energy reserves from less photosynthetic production.

One study determined that the ideal deer density in northeastern Illinois, based on T. grandiflorum as an indicator of overall understory health, is 4 to 6 animals per square kilometer (10 to 15 per sq.

[40][41][42] Trillium grandiflorum is susceptible to a greening disorder caused by bacterial organisms called phytoplasmas that alter the morphology of infected plants.

In 1971, Hooper, Case, and Meyers used electron microscopy to detect the presence of mycoplasma-like organisms (i.e., phytoplasmas) in T. grandiflorum with virescent petals.

In fact, the species is the most popular of its genus in cultivation, which has led to conservation concerns due to the majority of commercially available plants being collected from the wild.

In Quebec, Trillium grandiflorum is legally listed as vulnerable primarily due to habitat destruction in forests neighboring the province's most populous regions.

[47] In New York, Trillium grandiflorum is exploitably vulnerable since it is "likely to become threatened in the near future throughout all or a significant portion of its range within the state if causal factors continue unchecked" (NYCRR §193.3).

[citation needed] Due to the popularity of Trillium grandiflorum as a garden specimen, conservation concerns have been raised as the vast majority of plants sold in commercial nurseries are believed to be collected from the wild.

Frederick and Roberta Case, botanists who specialize in trilliums, wrote in 1997,[48] "to our knowledge, no true commercial quantity 'propagation' takes place at the present time."

[1] The species is vulnerable in Quebec, Georgia, and Illinois; and critically imperiled in Nova Scotia, Alabama, New Jersey, and South Carolina.