Seed Production and Spring Seedling Establishment of Diffuse and Spotted Knapweed
CitationSchirman, R. (1981). Seed production and spring seedling establishment of diffuse and spotted knapweed. Journal of Range Management, 34(1), 45-47.
PublisherSociety for Range Management
JournalJournal of Range Management
AbstractAnnual seed production of diffuse (Centurea diffusa) and spotted knapweed (Centurea maculosa) is reduced in dry years by a reduction in the number of viable seeds per seed head and increases when above-normal precipitation occurs by increase in the number of heads/flower stem. Seed production was approximately 1,000-fold that needed to maintain observed levels of infestation. Seedlings emerging in April had a high rate of survival with most plants flowering the following season, while those emerging after May 15 had a very low survival rate and almost no flower stem production the following season.