Propagation
Divide established clumps (rhizome) during winter.

Take root cuttings taken during winter.

Note:
Horseradish is a commonly used culinary herb that may be made into a sauce. It is also used medicinally to treat diuretic or as a digestive stimulant and for clearing mucous from nasal passages.

Care should be taken as contact with the sap may cause skin irritation. 

Botanic information
Leaf: The erect basal leaves are broad lanceolate to oblong with irregular lobes or serrations and have a long petiole. The stem leaves are alternate and lanceolate shape with crenate margins.
A fungicidal drench can be made from the leaves to treat other plants.

Flower: The small white ctateriform flowers have 4-petals and are arranged in a terminal panicle on a stem that appears from the leaf axils. The flowering period is long form early spring to midsummer.

Fruit: The small globular siliqua fruit appears continuously during the flowering period. The seeds are viable but the plant may be reproduced vegetatively.