Designing an Apple Tree Guild: Dynamic Nutrient Accumulators

In my previous article, I talked about a problem with sick soil on my property. After decades of monocrop farming with its attendant pesticide, herbicide and chemical fertilizer use, the land I now own needs some rehabilitating. Some of my diseased trees are apple trees, so today we will look at plant species that could form one part of an apple tree guild, building up the health of the soil and ultimately the health of the tree.

Depleted topsoil is a typical problem. Since fruit trees receive most of their nutrients from roots at this surface level it is important to revitalize the topsoil. Perennial plants with long tap roots can mine deep into the ground and bring up minerals that have been stripped away or depleted at the top. These plants are called dynamic nutrient accumulators. When these plants die back at the end of the season or are cut back during the season their leaves degrade into rich, topsoil-nourishing compost.

Some examples of nutrient accumulators are dandelions (Yes, stop killing them. They are telling you your soil is deficient and they are trying to fix it. When it is fixed, they tend to go away), chicory and yarrow. One of special note is comfrey. Comfrey will mine nitrogen, potassium, calcium, magnesium, iron and copper from as much as ten feet down. It grows tall with lush, thick leaves that can be slashed back several times a summer, providing a quick-degrading super-nutrient fertilizer to the struggling apple tree. Use the sterile varieties to prevent it from becoming invasive.

There are many other dynamic nutrient accumulators.  There are even tree species of nutrient accumulators like dogwood and shagbark hickory. The accumulators can be chosen by height to match the height of your main tree. So a dwarf tree would benefit from smaller plants and a standard could handle bigger ones. The size of the guild tree will also determine how many of the accumulator species to plant beneath it. I have a semi-dwarf apple and will plant 8-10 plants of comfrey around it.

Dynamic nutrient accumulators are probably one of the most important additions to an apple tree guild. Many also serve secondary purposes in mulching and attracting pollinators. We’ll examine more guild functions next time.

(Photo Credit)

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Julie Helms lives on eight acres with her family, sheep, goats and chickens.  She blogs about life on the farm at WoolyAcres.