OH WOW, nice tank! Very attractive layout with the combination of rock and DW.
The red ludwigia needs to be where the light is the strongest. Also it needs some current flowing on it as that seems to help keep the lower leaves on better. It will always loose lower leaves when it gets real tall. That's normal for it. Just trim off the lower half when it gets too bad and replant the top part. Being red, it likes a higher PO4 also. About 2 ppm PO4 will keep it happy. The swords, Hygro, Ludwigia, and wisteria also do better with root tabs close to them in the substrate, even with PPS dosing. If you aren't dosing Glut every morning, I strongly recommend it. You can use Excel or buy Metricide 14 on Amazon. You dose about 1 ml per 3 gal to start and then as growth speeds up in a month or two you go to 1 ml per 2 gal. Glut also helps fight algae. Hope this helps. Any other questions, feel free to ask. Good luck, OS.