Hygrophila polysperma 'Rosanervig' questions

[tiger15]

My Hygrophila polysperma 'Rosanervig' grows vigorously in my medium light CO2 tank with full foliage from top to bottom, but only get a touch of red on some tops. Unlike my other stems, what is unusual about it is that the red tops are not necessarily closest to the light, but can be in mid to lower levels of the stems. The green tops also lack veining pattern characteristic of the species.

How can I get more red from the plant. I also wonder why its foliage can close or open up in response to some trigger.

 

[Mick.Dk]

Hyg. pol. 'rosanervig' is a variety of Hyg. polysperma...... so each plant will have the potential/risk of producing branches, that will go back to original (=standard all-green). This is the case with all varieties - some varieties of plants are more prone to going back, than others. The non-green parts often do not contribute to photosynthesis, so the all-green branches usually grow faster and will eventually outcompete the variegated branches.
The trick is, to trim off the all-green branches as soon as they can be recognised, so the energy of the plant goes into the variegated branches.

 

[tiger15]

That makes sense similar to terrestrial variegated plants, such as liriope, has the tendency to revert back to all green form and need to prune away. So in pruning rosanervig, I can just hack all the green tops and let them branch out hopefully more variegated tops. This is unlike other stems to hack and discard the bottom, and replant the tops.

 

[three-fingers]

H.polysperma "Rosanverig" is a bit different from other red/variegated plant varieties in that the colouration is believed to be caused by infection of a specific virus as opposed to purely genetic traits, so it makes sense to me that it responds to light differently than other red plants .