Contrary to common belief, plantar warts (i.e. warts on the feet) do not have "roots" that extend deeper into the foot. The black dot that you may see below a wart is actually a dead and clogged blood vessel (a thrombosis). The vessel is deep below in your skin and not part of the wart. Plantar warts grow in the epidermis of the skin, meaning the outermost layer. Rarely if ever do they penetrate deeper into the dermal layer of the skin.
Warts can develop in many places on the body, not just on the feet. They are all caused by the Human Papillovirus (HPV). FYI: This is the same virus that can cause cervical cancer. They are very stubborn organisms and can be difficult to treat. Naturopathically, there are many anti-microbial herbs that can be applied to the wart to help kill it. Tea Tree (Melaleuca) and Pau D'arco (Tabebuia) are two herbs that have anti-viral properties. Tea Tree oil can be purchased and applied directly on the wart. In may or may sting, depending on the concentration of the cineol (one of its constituents) and on the sensitivity of the skin. If it stings, dilute the Tea Tree oil in a carrier oil, such as olive or sesame oil.