Waterways Rivers & Streams

Streams and rivers can be narrow, overgrown rivulets, a small, swiftly-flowing brook, or a large body of water that churns peacefully along. Natural streams and rivers meander through the landscape, offering a rich selection of edible plants. On the other hand, field drainage ditches and other man-made streams are often constructed out of cement and rarely have anything special to offer. If you forage aquatic plants near ditches or drains, you should try to figure out where the water is coming from, in order to avoid plants contaminated by fertilizer or pollutants.

From its source, a stream or river flows through many different landscapes on its way to the sea. It may pass through lakes, shady forests, and sunny meadows, each of which affects the diversity of plants growing in and along the water. When foraging along a stream or river, there are three things which will determine which plants you can expect to find: where in the course of the stream or river you are; the strength of the water flow; and the amount of nutrients in the water.

Parts of a stream or river

A stream or river can be split into three sections. The first lies closest to the source. Here the stream or river is narrow, and its swiftly-flowing water may be almost completely covered by vegetation. In this segment of the stream or river, you’ll find herbs like bitter cress and Japanese knotweed. In the second segment, multiple streams or rivulets join together into a wider flow that fosters cattails in the water and meadowsweet along the bank. Before it reaches its destination, the stream or river broadens, moving gently at the same height as the surrounding open landscape. You'll find fewer aquatic plants here, water mint often grows in mud near the bank.

Strength of water flow

Most aquatic plants need still soil to put down roots. If the current is strong, you should search for edible plants on the bank instead. Natural bends or small obstructions such as silt and twigs slow a stream or river, enabling some plants to establish. Keep an eye out for these types of changes in the flow.

Water nutrient level

The nutrient levels in a given body of water play a decisive role in the varieties of plants you'll find. Runoff from fertilized fields can increase the amount of nutrients, but so, too, do decomposing plants. High nutrient levels in the water bolster voracious stinging nettles, ground elder, and Japanese knotweed, enabling them to overtake other plants along the bank. Lower nutrient levels permit a greater variety of herbs to grow in and along the stream or river.

You'll get the most out of waterside foraging in spring and summer when tender herbs emerge. If winters are mild, some plants will be available year-round.

Spring

The first tender ground elder and stinging nettles appear in March along banks where the ground is damp. Meadowsweet will pop up in bright, open areas during the same period. From the beginning of April onward, there's a good chance of finding Japanese knotweed and water mint. Cattails begin growing in April as well, the reeds of which can be picked in the middle and lower parts of the stream through the beginning of summer. Starting in May, you can find watercress throughout the stream; shortly thereafter, it will drape much of the shoreline in green.

Summer

From June on, hardy plants like ground elder, stinging nettle, and Japanese knotweed can aggressively colonize broad stretches of land near nutrient-rich streams and rivers. Meadowsweet develops large, creamy-white blossoms at this time, while cattails disappear.

Late summer, fall, and winter

In late summer and until the first days of fall, you can still pick herbs along streams and rivers. However, plants that have received lots of sunlight over the summer may have turned bitter; you should taste your way around before harvesting in earnest. During the fall, you can pick mugwort in places where the stream snakes through the open landscape. By October, water mint and meadowsweet will have gone into hibernation. If a frost sets in, watercress will also die, but it can survive a mild winter.