Sarracenia, darlingtonia and flytraps flower in spring. Seeds are ready around december.
Sundews, at least spatulata and capensis seem to flower profusely yr. roud.
About what months do nepenthes flower in cultivation and how long does it take for seed produced by two plants to ripen?
For Nepenthes, they flower when they want or in the spring. The seed pods ripen in 2+ months because it depends on the species. Your best bet is to look it up, though.
Tropical Fish Enthusiast