Vegetative Response of Goldenweeds and Rayless Goldenrod to Simulated Mechanical Control

Abstract

Topgrowth was clipped at heights which simulated mechanical disturbance from potted common goldenweed, Drummond's goldenweed, and rayless goldenrod plants in the glasshouse. Resprouting occurred within days after clipping at the soil surface or at heights of 2 to 8 cm, but 50 to 100% of the plants clipped at the soil surface died within 5 to 10 weeks after treatment. No plants survived after topgrowth was removed at 2 cm below the soil surface. Mortality, numbers of adventitious sprouts on survivors, and stem elongation rates of regrowth varied little with species or phenological stage at treatment. Generally, topgrowth was completely replaced during the first growing season after clipping. Mechanical treatments which leave even small portions of rooted stems, such as shredding, roller chopping, or chaining, would not be effective against these undesirable subshrubs. Some control should be possible with blades such as the "stacker rake" which shears stems at ground level. Mechanical practices which sever the woody taproots at a shallow depth (discing or shallow root plowing) appear to be the most promising for control of these subshrubs.