Picking parts off a trillium plant can kill it even if the rhizome is left undisturbed.
Some species of trillium are listed as threatened or endangered and collecting these species may be illegal.
Laws in some jurisdictions may restrict the commercial exploitation of trilliums and prohibit collection without the landowner's permission.
In the US states of Michigan and Minnesota it is illegal to pick trilliums.
In New York it is illegal to pick the red trillium.

In 2009, a Private Members Bill was proposed in the Ontario legislature that would have made it illegal to in any way injure the common Trillium grandiflorum (white trillium) in the province (with some exceptions), however the bill was never passed.
 The rare Trillium flexipes (drooping trillium) is also protected by law in Ontario, because of its decreasing Canadian population.

High white-tailed deer population density has been shown to decrease or eliminate trillium in an area, particularly white trillium.

Some species are harvested from the wild to an unsustainable degree.
This is particularly dire in the case of T. govanianum, whose high selling-price as a folk medicine has motivated harvesters to destroy swathes of ecologically sensitive Himalayan forests, causing mudslides.
Picking parts off a trillium plant can kill it even if the rhizome is left undisturbed. Some species of trillium are listed as threatened or endangered and collecting these species may be illegal. Laws in some jurisdictions may restrict the commercial exploitation of trilliums and prohibit collection without the landowner's permission. In the US states of Michigan and Minnesota it is illegal to pick trilliums. In New York it is illegal to pick the red trillium.
In 2009, a Private Members Bill was proposed in the Ontario legislature that would have made it illegal to in any way injure the common Trillium grandiflorum (white trillium) in the province (with some exceptions), however the bill was never passed.  The rare Trillium flexipes (drooping trillium) is also protected by law in Ontario, because of its decreasing Canadian population.
High white-tailed deer population density has been shown to decrease or eliminate trillium in an area, particularly white trillium.
Some species are harvested from the wild to an unsustainable degree. This is particularly dire in the case of T. govanianum, whose high selling-price as a folk medicine has motivated harvesters to destroy swathes of ecologically sensitive Himalayan forests, causing mudslides.
Trillium