Useful Plants To Chop and Drop in a Forest Garden

Chopping and dropping certain plants within a forest garden scheme can improve the soil, increase or maintain fertility, and increase the overall yield from the system. In this article, I will share some of the plants I find most useful as "chop and drop" plants within such a system. These are examples both from my own forest gardens, and other forest garden designs I have worked on. 

What does it mean to chop and drop?

First of all, if you are not already familiar with the concept, chopping and dropping is exactly what it sounds like. It involves simply chopping off organic material and dropping it as a mulch around nearby plants–most commonly around a fruit tree in a fruit tree guild or forest garden–though also in other garden systems. 

The plants that you chop and drop are good at gathering certain plant nutrients–often nitrogen but also potassium and other nutrients to keep your plants in good health. When you chop material from these plants and lay it on the soil surface, the nutrients they contain will slowly break down and return those nutrients to the soil, where, at some point, they will be available for the uptake of other plants in the vicinity. 

Some chop and drop plants are nitrogen fixers, which work with bacteria in root rhizomes to take in atmospheric nitrogen. Others may be especially deep-rooted, particularly good at gathering certain nutrients or simply quickly generate a large amount of biomass which can be useful as a mulch in your garden. 

Trees to chop and drop in a forest garden

Trees can of course be very important within the overall forest garden design. But the trees within the scheme should not just be included for their edible yields. Trees can also be very important as pioneer plants to establish the scheme, and also as coppiced or chop and drop plants within the system. 

My top picks for forest garden sites in a range of different climates and conditions include:

• Acacias
• Alder ssp.
• Black locust
• Laburnum
• Mesquite
• Mimosa
• Redbud
• Siberian pea tree

Of course, these are not the only trees that generate biomass that can be used to feed the soil and improve fertility when the material is chopped and dropped and laid as mulch throughout the system. 

Shrubs to Chop and Drop in a Forest Garden

In my climate and the conditions in which I garden, shrubs are important nitrogen fixers. I use Elaeagnus spp. E. multiflora and E. umbellata. (Though, it should be noted that these can be invasive in some areas.) Some shrubs which are particularly useful for nitrogen-rich mulch material are:

• Amorpha fruticosa
• Brooms
• Buckthorns
• Ceanothus
• Elaeagnus spp.
• Myrica cerifera
• Shepherdia spp.

It is a good idea to consider including nitrogen-fixing shrubs within a forest garden design. 

Top Herbaceous Perennials for Chopping and Dropping

Nitrogen fixing plants are also found within the herbaceous layers of a forest garden. Some particularly useful nitrogen fixers for these lower layers of a forest garden include:

• Clovers
• Lathyrus latifolius
• Wood vetch (and other vetches)

However, it is also important to note that nitrogen is not the only plant nutrient that can be replenished through chopping and dropping. In forest gardens and fruit tree guilds, it can also be useful to chop and drop dynamic accumulators which are good at accumulating other macro and micronutrients for good plant health. 

Comfrey is one of the best known dynamic accumulators, and I do indeed see great results when a use comfrey extensively as a mulch throughout my garden. But comfrey is certainly not the only plant which can be useful in this way. Other herbaceous perennials I find it useful to chop and drop in addition to the above include:

• Dandelions
• Hogweed
• Jerusalem artichoke, cardoons, sunchokes
• Rhubarb
• Rumex ssp.
• Yarrow

Annuals for Chopping and Dropping

Finally, I also allow annuals to self seed. These can also be chopped, dropped and used as mulch in the forest garden. Some of the most useful annuals for chopping and dropping are:

• Amaranthus spp.
• Borage
• Chenopodium album

Though of course the plants listed above are just a few examples, perhaps they will help you plan and plant for long-term fertility in your forest garden.