Spring cress blooms March–June and has white, four-petaled flowers that are relatively large, compared to other mustards. It is an edible plant and usually grows in damp or wet soils.
Spring cress is a low, spreading perennial wildflower that grows to about 1 foot tall. It has a single, erect stem that branches sparingly at the flower cluster. The rootstock is a short, tuberous, unsegmented rhizome (sometimes constricted into 2 or 3 segments).
The flowers, when fully spread open, are about ½ inch across (which is rather large, for a mustard); they have 4 green sepals and 4 white petals (sometimes faintly tinged with pink), and arise at stem tips in small clusters.
Blooms March–June.
Leaves: There are both basal and alternate stem leaves. The stem leaves vary: When the plant's roots are in water, the stem leaves are narrowly lance-shaped; when the plant is rooted in wet earth, the stem leaves are triangular with some teeth, the lower on long petioles, the upper to nearly sessile. The basal leaves are rounded on long stems.
The fruits are slender pods (siliques) that grow to about 1 inch long and split lengthwise to release seeds; these mature first at the bottom of the flower clusters, with the youngest flowers and flower buds at the top of the flower clusters.
Similar species: Eight species of bitter cress (genus Cardamine) have been recorded for Missouri; five are ones you are most likely to encounter or possibly confuse with spring bitter cress:
- Purple, or northern bitter cress (Cardamine douglassii), is most similar to spring bitter cress, but it has pink or purplish pink (not white) flowers, and its stems have spreading hairs (at least in the top half of the plant); it blooms about two weeks earlier than spring bitter cress. Also, in Missouri almost all its populations are in the northeastern quarter of the state (a disjunct occurrence is in Cape Girardeau County).
- Small-flowered, or sand bitter cress (Cardamine parviflora), is an annual, with much smaller flowers; it blooms March–July. It grows up to 12 inches tall and has mostly single stems with little to no branching. Its basal and stem leaves have 3–6 pairs of small, opposite lobes spaced along the leaf rib, the terminal having the same nearly linear shape. It grows statewide, in upland, rocky woods and ridges.
- Pennsylvania bitter cress (Cardamine pensylvanica) is an annual, with stems single or spreading, to 2 feet tall. Blooms March–July. Its leaves are like C. parviflora, but larger, and the lobes are connected by leaf tissue along the midrib of the leaf. It grows in moist places in Missouri's central and southern counties.
- Hoary bitter cress (Cardamine hirsuta) is an annual, similar to small-flowered and Pennsylvania bitter cresses, but with numerous basal leaves at flowering time that have their leaf stems with spreading hairs; the fruits are erect (not ascending or spreading). It is introduced, uncommon, but widely scattered in Missouri.
- Toothwort (Cardamine concatenata) is a perennial, common, well-known spring wildflower with conspicuous, palmately lobed, toothed leaves that at first glance look something like cannabis leaves.
Height: to 12 inches.
Scattered in the southern, central, and northeastern portions of the state.
Habitat and Conservation
Occurs in bottomland forests, wet places, fens, and banks of springs and spring branches. Often associated with calcareous soils. It is sometimes also found in seepy bluffs and acid seeps.
Sometimes grows as an emergent aquatic plant.
Status
Native Missouri wildflower.
Human Connections
The roots, stems, and leaves of spring cress have a bitter or pungent flavor, similar to horseradish. It is sometimes used as a condiment, in sauces, and in salads.
The name “cress” is used for many plants in the mustard family, such as watercress and field cress. Cress usually refers to mustard-family plants with small white flowers and peppery-tasting leaves.
Compared to many other plants in the mustard family, spring cress bears rather showy flowers.
Ecosystem Connections
Spring cress flowers are visited by a variety of bees, flies, and butterflies, which gather nectar and often pollinate the plant, too.
Nearly all the members of the mustard family, including broccoli and radishes, have flowers with four petals. An older name for the family, Cruciferae, refers to the cross-shaped flowers.
The bitter, pungent flavors characteristic of mustard-family plants are caused by a variety of glucosinolates and related chemicals. We humans have discovered that a squirt of mustard tastes great on hot dogs; radishes and arugula add a pleasant peppery bite to green salads; wasabi adds excitement to sushi; and horseradish is dandy in a creamy coleslaw. But these chemicals, in high enough levels, also function to deter herbivores from eating the plants.
Many insects, however, are adapted to eating mustard-family plants. The cabbage white butterfly, for example, exclusively uses plants in this family as its caterpillar food plant. Some insects concentrate the mustards' toxic chemicals in their bodies and gain protection from predators that way.
