Some plants are particularly good at pulling nutrients from the soil into their roots and storing it in their leaves and tissues.. These clever plants are referred to as dynamic accumulators. Gardeners have long been taking advantage of these plants as organic fertilizer. While no one seems to have done a study to back up the idea that the leaves will release the nutrients back into the soil, for other plants to take advantage of, it makes sense to most gardeners and the practice continues. Remember, studies are only done when there is money to fund them and there isn’t much money in organic gardening.
One non-gardening use for dynamic accumulators is reclaiming soil that has been contaminated by heavy metals. This process is called phytoaccumulation or hyperaccumulation. The plants are allowed to take up minerals through the growing season and then they are harvested and the minerals are extracted and recycled.
But for our purposes as backyard gardeners, we’ll stick with using them as free fertilizer.
You can make use of these accumulator plants in several ways.
❧ The easiest use is to too them in the compost pile. They will slowly release their nutrients, as the debris in the pile turns to usable compost.
❧ You could simply layer the leaves on the soil in the garden. If you don’t like the look of a dying leaf mulch or if they tend to blow around, cover them with a dusting of soil or compost.
❧ The leaves can be brewed into a fertilizer tea. Just pack them into a bucket or barrel, fill with water and let it steep for a 1 – 3 weeks. The usual proportions are 10 parts water to one part leaves.
Give the mix a stir daily, to mix things up. If you don’t want to strain the leaves when the brew is done, put them in some type of netted sack instead of straight in the water.
❧ One final way to make use of dynamic accumulators is to plant them in your garden. I’m not quite sure how much they actually improve the soil and most of them are considered weeds, but if you like the natural approach, it won’t take any extra effort.
Some Dynamic Accumulators to Use
Most of the plants that are able to accumulate nutrients from the soil have deep tap roots. That’s something to keep in mind before you plant them – they will be hard to remove. However some, like corn salad and chamomile, are edible crops and other, like bee balm and yarrow, are ornamental plants.
Bee Balm (Monarda spp.)
Birdsfoot Trefoil (Lotus corniculatus)
Borage (Borago officinalis)
Chamomile (Matricaria recutita)
Chickweed (Stellaria media)
Chicory (Cichorium intybus)
Cleavers (Galium aparine)
Clover (Trifolium spp.)
Comfrey (Symphytum officinale)
Corn Salad (Valerianella locusta)
Cup Plant (Silphium perfoliatum)
Dandelion (Taraxacum officinale var. sativa)
Dock (Rumex obtusifolius)
Garden Cress (Lepidium sativum)
Hairy Vetch (Vicia villosa)
Horsetail (Equisetum spp.)
Lamb’s Quarters (Chenopodium album)
Meadowsweet (Filipendula ulmaria)
Miner’s Lettuce (Claytonia perfoliata)
Pigweed Amaranth (Amaranthus Retroflexus)
Plantain (Plantago spp.)
Salad Burnet (Sanguisorba minor)
Stinging Nettle (Urtica dioica)
Yarrow (Achillea millefolium)