Well this plant didn't do well for me in over a year of being in my tank. I've had descent luck keeping my crypts in container just to manage them from creeping all over the tank and they are a lot more forgiving when I move them around if I'm changing the scape. (this avoids crypt melt in the same tank for me.) In my containers I add mineralized soil capped with the same substrate in the tank and this crypt exploded in 3 months. You sill have to go through the trouble of transplanting if you see issues like the roots choking themselves out which is I use containers as translucent as possible. The container also keeps the crypts in a more attractive bunch and easier to identify but that's just my opinion. I also use containers that are easily hidden in scape.Well my C. blassii (so called, lol) never looked like that!, leaf front or back!! But I didn't have co2 or much in the way of ferts... maybe a different variety?
Go Jay! We all love your tank & plants! & learn from you, keep it up!
Oh and I keep forgetting I think the TAG article imply the correct name is C. cordata var. siamensis