Fall-planted longspine sandbur began to emerge in April, peaked in late April or May, and continued at low levels through October. During the first year after seeding, 98% of the total seedlings emerged prior to June. Fall-planted puncturevine began to emerge in late April or May and continued through October. Puncturevine emergence was multipeaked and 75% of each season's total emerged prior to mid-July. A similar number of puncturevine seedlings emerged the second and third years after planting as in the first. The emergence pattern for a species was similar each year regardless of how long the seed had lain in the soil. Longspine sandbur required 7 to 13 weeks from emergence to heading and produced approximately 2600, 1300, 180, and 3 spikes per plant when planted in May, June, July, and August, respectively. Puncturevine flowered within 3 to 4 weeks after emergence when temperatures were favorable and produced an average of 5600, 5200, 3600, and 200 burs per plant when planted in May, June, July, and August, respectively.