The vegetation within vernal pools can vary greatly. Some vernal pools may have little to no plants growing in them, while other pools may be dominated by trees, shrubs, grasses, or sedges. In some pools, annual plants may become established after the pool dries up. Plants play an important role in vernal pools. They provide food and nutrients for animals that live in or use vernal pools. The vegetation in and around vernal pools also impact the temperature and amount of water in the pools and how long they stay flooded, which can influence the types of animals living in the pools and their growth rates.
Early Wet Vernal Pool. Photo: MNFI
Late Wet Vernal Pool. Photo: MNFI
The plants found in and around vernal pools are similar to those found in the surrounding forest, but also may contain species adapted to growing in wetter conditions. Common trees and shrubs of vernal pools in Michigan include red maple (Acer rubrum), silver maple (Acer saccharinum), black ash (Fraxinus nigra), yellow birch (Betula alleghaniensis), American elm (Ulmus americana), white pine (Pinus strobus), eastern hemlock (Tsuga canadensis), northern white-cedar (Thuja occidentalis), willow (Salix sp.), buttonbush (Cephalanthus occidentalis), speckled alder (Alnus incana), winterberry (Ilex verticillata), and dogwood (Cornus sp.). Common herbaceous or non-woody plants found in vernal pools include duckweed (Lemna sp.), sphagnum moss (Sphagnum sp.), tree moss (Climacium dendroides), jewelweed (Impatiens capensis), blue-joint grass (Calamagrostis canadensis), wool-grass (Scirpus cyperinus), false nettle (Boehmeria cylindrical), mad-dog skullcap (Scutellaria lateriflora), northern bugleweed (Lycopus uniflorus), harlequin blueflag (Iris versicolor), sensitive fern (Onoclea sensibilis), rushes (Juncus sp.), and sedges (Carex sp.). Several rare plants are associated with vernal pools in Michigan, including Shumard’s oak (Quercus shumardii, special concern), raven’s-foot sedge (Carex crus-corvi, state endangered), squarrose sedge (Carex squarrosa, special concern), and false hop sedge (Carex lupuliformis, state threatened).
Jewelweed. Photo: Mike Penskar