The dormant tubers require a sufficiently warmed-up soil to germinate, i.e. from April to autumn. During germination of the mother tubers, one or more vertical rhizomes develop. Basal bulbs form on these rhizomes near the soil’s surface. These basal bulbs then form shoots, as well as secondary rhizomes and basal bulbs. A tuber formed the previous year can thus give rise to numerous individual new plants.
During the regenerative phase, the rhizomes differentiate into tubers. Tuber formation begins at the end of May, or earlier for crops under netting/plastic, and carries on all summer, until the first frost. The plant overwinters in the form of tubers. We have observed that tubers survive at temperatures of as low as -10° C at the soil’s surface. The majority of the tubers are to be found in the surface layer of the soil (down to 15cm), but certain ones can form at a depth of as low as 50cm from the surface, depending on soil type.
The vegetative and regenerative phases occur at the same time.
Flowering takes place from June onwards, or earlier in crops under netting or plastic. Although germination from seed is probably possible in Switzerland (research is currently underway at Agroscope), tubers constitute the main means of propagation.
Stoller E. W., Sweet R. D. (1987): Biology and life cycle of purple and yellow nutsedges (Cyperus rotundus and C. esculentus).
Weed Technology 1: 66-73.
Weed science in Field Crops and Viticulture - Changins
Vegetable Growing - Wädenswil