Why isn't the milkweed growing in my habitat flowering?

Different species of milkweed have different growth strategies, so it depends on what species you have. In general, milkweed may not flower in the first year of growth, because it is investing its resources in growing a strong root system. Also, if there is excess nitrogen in the soil the plant may not flower, so do not fertilize milkweed. Finally, milkweed may not bloom if the plant is stressed, such as by drought or excessive heat. Luckily, monarchs will lay their eggs on milkweed even if it is not flowering! The caterpillars eat the leaves of the plant, so your milkweed can still be a host plant without flowers. Milkweed may also spread through its root system (depending on the species), so the plant may spread that way despite not flowering or going to seed.