The growth and flowering of ‘Rupert’ and ‘Ronina’ lachenalia (Lachenalia) in a greenhouse environment were manipulated by varying planting times and flurprimidol treatments. Bulbs were planted in November, December, January, and February. At each planting date, the following flurprimidol treatments were tested: soaking the bulbs before planting (15 and 30 mg·L−1) or a single foliar spray (15, 30, 45, and 60 mg·L−1). The results showed that foliar application of flurprimidol was ineffective in controlling inflorescence stem height and inflorescence length; only soaking bulbs of ‘Rupert’ in flurprimidol at the concentration of 30 mg·L−1 shortened the inflorescence stem height. Moreover, soaking bulbs in the concentration of 30 mg·L−1 may be recommended for potted lachenalia production, as shorter and wider leaves were obtained and every planted bulb emerged and flowered. The later the date of planting of the bulbs, the more quickly the plants began to flower. As planting time was delayed, inflorescence stem length and leaf length decreased, and the number of florets and leaf width increased. Soaking the bulbs in the retardant (30 mg·L−1) delayed the emergence of flowers for 5–6 days, but the retardant did not affect the number of leaves or the number of florets per inflorescence. Regardless of the factors applied, the two cultivars of lachenalia differed with respect to each of the analyzed traits.