There was a time when people relied on wild foods as a crop to supplement their diet and reduce grocery costs. Wild berries were gathered in the summer to make jelly, jams, and pies; roots and nuts were gathered in the fall to use in baked goods, and greens were gathered in the spring. As wild habitats began declining, concerns were raised about depleting the natural populations and how much can be gathered without harming the environment.
If harvested sustainably, an area will continue to produce year after year. Become familiar with the plants in your area and find out which ones are rare or endangered. Avoid picking from these plants or pick sparingly, depending on the part being gathered. However, you too are a part of the natural world, and by approaching the plants with a conscientious attitude, you can forage in the wild without harming the natural population.
When looking for plants to gather, if you only see a single plant here and there, don't pick it. If you see a few here, and a few there, pick only what you need. If the plant is abundant, and especially if it is invasive, pick all you want, but use what you pick.
Many wild greens come from plants that are annuals, such as chickweeds or cresses. Others, like evening primrose and thistle, are biennials. They bloom, produce seed, and then die, to be replaced by seedlings that sprout from seeds they have produced. They rely on seed production to reproduce. Others are perennials, like dandelions. Even if you remove all the leaves, they will continue to grow.
If the plant has a rosette of leaves near the ground, you can remove the younger leaves without uprooting or harming the plant. Annuals and biennials often come up thick and can benefit from being thinned by being pulled out and the roots trimmed off. Other greens have branches that can be snipped off at the tips and the plant will continue to grow. Young leaves are generally milder tasting and more tender.
Flowers are the reproductive part of the plant. Many of them are edible. A number of plants produce both edible flowers and edible fruits or seeds. Gathering the flowers will prevent them from producing fruit and going to seed. Sometimes you have to choose whether to eat the flowers now or wait and pick the fruits later. An ideal situation is when there are enough plants to do both.
Flowers also provide nectar for pollinating insects. Plants in turn depend on the insects to pollinate them so they will produce fruit. Even if it is a wildflower or shrub with no edible parts, the pollinators will still visit their flowers for nectar. Leave these for the pollinators.
Seeds are contained within the fruits of plants. Fruits may be berries, drupes, hips, nuts, legumes, or capsules that provide food for animals that in turn disperse their seeds. Since many of these fruits are edible, care should be taken to leave some for the wildlife. When appropriate, disperse fruits and seeds to extend their range.
Berries are bird food. Fruit-eating birds rely on wild fruits for survival. Some seeds have to pass through the digestive system of birds before they will germinate. A symbiotic relationship has developed in which the plant provides the fruit for the bird and the bird provides the means for planting its seeds. When gathering berries, remember to leave some for the birds, some to reseed, and some for the next group of foragers.
Nuts provide food for squirrels, turkeys, and other wildlife. Squirrels gather nuts and bury them for storage but don't always remember where they buried them. The forgotten nuts become sprouts the next spring and eventually grow into a tree.
Digging up roots often means destroying the plants. You don't want to be the cause of a population becoming rare. In some cases roots can be divided and replanted, especially those with tubers. Some roots can have the top part removed and the bottom part containing the root hairs replanted.