Both Limn. and Rot. exibit species, that are quite difficult to "get on land". Myr.s can be even harder......
- one trick is to use oldest parts of stem - totally defoliage - plant deep, only 1cm. above soil - and wait for new growth. This will be adapted.
- another trick is to limit space - put some kind of fine net around the plant - let it grow on and "jam the space" - wait for it to force itself above surface, doing new growth. This will be adapted.
After that, you let the adapted parts grow bigger and then take cuttings to produce a potted plant for flowering.
.........simple as that (but it takes time 😉 )