Threadleaf snakeweed exhibits some degree of summer deciduousness.
Seedlings produce a single stem and a taproot.
A yearling has three to four stems. In an arid New Mexico grassland, seedling survival was five times greater where competing vegetation had been removed than on undisturbed sites. Although the ranges of the two perennial snakeweeds overlap, they appear to occupy slightly different niches. Prolific seed production and buried seeds permit opportunistic seedling recruitment during favorable periods. New terminal growth begins on basal stems from January through March.