Ninety-nine percent of viable seeds will germinate in the first 2 years. Temperature is the most important requirement for germination. Alternating freezing and thawing, wet and dry periods, and shortened photoperiod promote germination. If adequate moisture is present, germination can occur throughout the growing season. Although a successful seed producer, the primary way an established patch of leafy spurge spreads is through its extensive lateral root system.
Vegetative reproduction occurs from both crown and root buds.
The majority of the plants in the center of a patch are the result of crown buds, while the plants growing on the edge of a patch are primarily from lateral root buds. The crown buds are the first to form. Crown buds begin to develop 7 to 10 days after seedling emergence. Lateral roots and buds will begin to develop as the plants mature. Roots may either be long or short.