Dynamic Accumulators

These plants excel at gathering nutrients and accumulating them in their tissues. Once these dynamic accumulators decay, whether naturally or via composting, those nutrients are released into the soil and become available to other plants. Dynamic accumulators can do much of the work of building soil. We don’t know everything about how these plants work and where in the plants most of the nutrients accumulate. Certainly much of it happens in their roots, which are in the topsoil layers. Some scientists also believe that deep-rooted plants can pick up nutrients from deeper soil layers, but this theory is still being researched. Comfrey is an excellent example of a deep-rooting herbaceous plant that accumulates nutrients, including potassium, phosphorus, calcium, copper, iron, and magnesium. Watercress, a floating aquatic perennial, accumulates many nutrients. Some other excellent dynamic accumulators are stinging nettle, black locust, dandelion, sorrel, dock, black walnut, and shagbark hickory.

(From The Permaculture Promise by Jono Neiger)