Tall fescue and red fescue are often used as cover crops but may be allelopathic to black walnut roots. Mowing is a well-known weed control method and is effective between rows. However, because it does not kill the weeds, the grower must monitor weed growth regularly and mow often. Mulches may be applied with varying success. Plastic mulches are difficult to keep in place and are not very long lasting.
Shingles are long lasting but can be blown around by strong winds.
Wood chips and sawdust are sometimes effective for a season or two if perennial weeds have been removed first. Protective tree tubes are in the demonstration stage, but are expensive. Herbicide restrictions change frequently. For example, the forestry section has been removed from several simazine labels. Oust is now registered for preplanting and post-planting application in over the top of several tree species.