This Ludwigia is also new to me. Does it grow more slowly than L. ovalis? The stems appear to me a little sturdier than in ovalis, rather like L. glandulosa, except for the different leaves. And, once again, more information about its identity may be gained by growing emersed and flowering it. And Ludwigia hybrids are possible.
Generally, it's really unsatisfactory that so many new aquarium plants pop up in the trade and hobby without any background information published by the breeders or traders who introduced the plants first.
Gruß
Heiko