Bush encroachment into rangelands is a topical issue across the globe, especially in semiarid regions, including southern Africa. Because this has negative implications for livestock production and biodiversity conservation, effective and sustainable methods for managing bush encroachment should be explored. This study aimed to compare the efficacy of four methods of bush control (manual uprooting, fire, chemical control, and high-density overnight kraaling [HDOK]) on herbaceous vegetation and bush species in a montane rangeland in Sehlabathebe, Qacha’s Nek District, Lesotho. The study conducted a field experiment in which four bush control treatments were applied to different sections of a rangeland for one season. Herbaceous vegetation and shrub vegetation attributes were assessed before and after bush control treatments. The assessment recorded a total of 92 herbaceous species, belonging to 68 genera and 25 families, before treatments and a total of 147 species, belonging to 102 genera and 37 families, after treatments. There was a significant increase in herbaceous species richness following fire and manual uprooting bush control treatments (p < 0.001). The abundance of forb species (p < 0.01) was enhanced by fire, while the abundance of highly palatable grass species was enhanced by HDOK. The analysis of the four most frequent bush species revealed that Chrysocoma ciliata, Helichrysum trilineatum, Inulanthera thodei, and Selago flanaganii were significantly reduced by manual uprooting, fire, and HDOK bush control treatments. HDOK was the most effective method, followed by manual uprooting, fire, and chemical control, in decreasing order of effectiveness. In addition, a significant decrease (p < 0.01) in bush species richness and evenness was recorded following the HDOK treatment. Thus, the study demonstrated important preliminary evidence that HDOK could be the best method for bush control in the montane rangelands of Lesotho, followed by manual uprooting, fire, and chemical control, in that order.