I had a small bunch that I planted in a medium light, no fert tank and within three weeks it had grown significantly. In lower light situations I read it tends to grow upwards, in my tank with medium light it is as tall as three inches in some places. Grows like wildfire in the right conditions.
It can get very tall! the way people often have to trim jungle val is how i have to trim my bacopa australis, it will cover the top of my tank in a month if i do not! I have also been experimenting with it trying to grow a carpet...i've noticed if you start to regularly trim it real short (like an inch or two off the ground) the upward growth gets really stunted and grows very slowly. To get it to be a foreground plant like in the picture, you need very high lighting, at least from my experience.