How to Measure Asexual Reproduction in Lythrum Cultivars

Estimate the number of years that a particular lythrum cultivar has been alive. The best way to determine the plant's age is to ask the nursery its age when you are buying it; however, if it is a plant you have had for a while, this may not be feasible. If the specimen has more than fifty stalks, it is at least three years old. The root spread slows down after a plant reaches maturity, between three and five years.

Measure the ground area covered by your lythrum cultivar specimen. Since the only type of asexual reproduction that lythrum undergoes is root spreading, the level of asexual reproduction in purple loosestrife is based on the average increase over time in ground area covered by the plant.

Divide the area the plant currently occupies by the length of time it has taken it to reach this size to achieve a measure for its rate of asexual reproduction. Since there is no standardized unit of asexual reproduction, you can use any units you like for area and time -- square inches per month, square feet per year, square centimeters per week. However, because it is difficult to convert such unit combinations, it is best to choose units that will be most useful and precise for you. The most important factors are the current size of your plant (choose the unit that will offer the most precise measurement, without being too minute), and how well you can estimate its current age.