Native Americans cultivated special prairie plants for food and medicine in gardens close to their homes, and pioneers learned from them how important these gardens were to survival. Pioneer families worked hard every day and did not weed for appearance, worrying mainly about strong weeds that would spread and choke out the good plants. After about 4 years, the gardens became strong enough to crowd out weaker weeds on their own. Over the winter, dried stalks and overgrown leaves were left in place to provide food and shelter for birds and animals and to help protect valuable plants from the cold and wind.