The theme for April is medicine. The purple dead nettle is a plant introduced from England for its medicinal properties. It is supposedly an anti-inflammatory, anti-bacterial and anti-fungal. (see here)
This little flower is an invasive plant from Europe. British settlers brought it over for food and medicine. It was used to make beer before the use of hops. It has a few names: Creeping Charlie, Ground Ivy and Ale Ivy.