Hemlock is the predominant plant species within the gorge. The hemlock's root system takes up much of the available nutrient material in the soil. Its boughs shade out much sunlight, inhibiting the growth of all but the most shade-tolerant plants. In addition, the high rock walls of the gorge shut out direct sunlight and trap evaporation from the stream, maintaining a cool, damp microclimate.

Three other trees also grow well in these conditions and can be found along the trail. Beech trees have a smooth, light gray bark and a muscular-looking trunk. The yellow birch is distinguished by its yellow-silver bark that separates from the trunk in thin, film-like curls. It is a valuable timber tree in northern New Hampshire. The black birch has smooth, dark gray bark that emits a pungent, sweet odor when its twigs are broken.

On the forest floor you may see the dark green leaves of the wintergreen plant. The leaves of this small creeping vine have the pleasant smell of mint when crushed. Other moisture-loving, shade-tolerant plants, such as mosses and ferns, are plentiful.

Lichens, the hardiest of all plants, grow on rocks. Lichens are a mixture of fungi and algae. A fungus feeds on an alga, and the alga receives protection from wind and water loss from the fungus. This symbiotic relationship allows them to grow together when neither could on its own. Lichens can tolerate low levels of light and require no soil. A pioneer species, lichens tend to break down the surface of the rock, causing soil material to accumulate. This enables other plants, such as mosses, to grow.