Large-flowered trillium in bloom.

Trillium grandiflorum

Large-flowered Trillium  is on of Wisconsin’s late spring/early summer woodland ephemerals, typically found in deciduous and mixed upland forests.  It has three white petals that overlay three leaf-life structures called bracts. Trillium is one of many plants whose seeds are spread by ants, and it can be seriously damaged if the flower is picked.  The height of this species has also been shown to be an effective index of how intense foraging by deer is in a particular area.

Project Budburst’s Plant ID Page

Project Budburst’s Trillium Phenophase ID


  1. First Flower: Date the first flowers are fully open. When open, you will see the stamens among the unfolded petals.
  2. Full Flower: Date when half or more of the flowers are completely open
  3. First Ripe Fruit: Date when you notice the first fruits becoming fully ripe or seeds dropping naturally from the plant. The fruit is a light green rounded capsule with thick walls which grows at the top of the stem. Ripening is usually indicated by the fruit beginning to fall off of the plant.
  4. Full Fruiting: Date when half or more of the fruits are completely ripe or seeds are dropping naturally from the plant.
  5. All Leaves Withered: Date when most or all of the leaves that developed this season, have lost green color or are dried and dead.

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