Here's a great article from Tropica about this plant written by our friend and brilliant aquascaper George Farmer: https://tropica.com/en/articles/ludwigia-palustris/

This cosmopolitan stem plant turns red easier and is smaller than the well-known Ludwigia repens ’Rubin’.
Each stalk becomes 2-4 cm wide and 10-30 cm high. The plant willingly creates side shoots, but cutting increases the amount and the plant becomes even denser. The cut-off shoots quickly generate new roots when planted.
The plant becomes intensely red and grows better, when placed in light and with added CO2.

Pots are brimming with plants and have lots of mass and healthy,
well-developed roots.
Most pots can be divided into several portions or individual plants which are planted separately.