How to Prune Kerria Roots

Kerria japonica is a flowering deciduous shrub species with a vigorous and slightly wild growth habit. The shrub puts on a bright display of golden flowers in the spring along elongated, bramble-like woody stems. The vigorous growth habit can translate into a robust root system. Whether the roots are invading nearby plantings or simply proving to be a tripping hazard, they can be judiciously pruned back. Root pruning can also be done to slow the overall growth rate of the shrub, limiting the amount of above-ground pruning you will need to do. It also often has the effect of shocking the shrub into producing more flowers, advises North Carolina State University. Conduct root pruning in the late spring or early summer after flowering to preserve that year's bloom and not stress the plant. If you are agnostic about the temporary impact on flowering, root-prune in the early spring once the soil is thawed and easily worked.

Things You'll Need

• Spade
• Shovel
• Loppers

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Instructions

1. • 1

     Sever the offending subsurface roots by driving a spade straight down in the soil and then lever the larger loose pieces of root out with the spade, before composting or discarding them.

   • 2

     Excavate the soil around larger roots or those that have pierced the the soil surface with a shovel. Sever the unwanted root portions with the blade of the shovel or a spade or with a pair of loppers, as needed. Remove as much of the severed roots as possible, chipping and composting or discarding them.

   • 3

     Redistribute any displaced soil around the root ball, tamping the soil lightly. Immediately after root pruning water thoroughly to drench the entire remaining root mass in order to prevent drought stress. Maintain a consistent irrigation regimen, as the shrub will need moist soil to recover from the pruning.