Alkaloid Content of Duncecap Larkspur after Two Years of Clipping

Abstract

Duncecap larkspur plants clipped in vegetative growth stage (late June) for 2 consecutive years produced only leaves and no flower stalks the third year. These plants were significantly smaller and contained a significantly lower concentration of total alkaloids than those plants clipped later in the summer or than unclipped control plants. This susceptibility to injury by clipping may help interpret results of other control methods. Total alkaloid content of previously unclipped larkspur plants was highest in the early growth stages and declined throughout the summer. Total alkaloid content in late June ranged from 1.7% to 2.8% and was not correlated with amount or pattern of precipitation.