Pilea peperomiodes is most commonly referred to as a 'Chinese money plant'. Your plant is indeed Pachira aquatica, which is commonly sold as a 'money plant' without the 'Chinese' part. It's also referred to by at least another half dozen common names, thus the confusion.
Your plant likes a fast draining medium that is moist or damp - never wet or soggy. It's important to know that if this plant might grow near a water source where it naturally occurs, it won't tolerate wet or soggy conditions in a conventional container planting; this, because a container radically changes the way water behaves in the grow medium in contrast to how it behaves in the earth.
You can keep track of when your plant needs its next watering by inserting a wooden "tell" deep into the grow medium, all the way to the bottom of the pot. Water when it comes out nearly but not completely dry. The best material to make a "tell" is a wooden dowel rod you can but at any hardware for $1-2. Cut a 1/4" dowel rod in half and sharpen the tip in a pencil sharpener and you're done. For shallow pots, you can make several from each 48" rod.
Getting your watering intervals right is an important part of any care regimen, and the more water-retentive your grow medium is, the more important it is to avoid watering too soon.
Does it like being pot bound No. When the answer is given from the plant's perspective, the answer is 'No'. No plant likes or prefers to be pot bound because root congestion is a limiting condition, and can actually eliminate nearly every bit of potential for growth, vitality, eye appeal, and the plant's ability to defend itself as the congestion gets progressively worse. The plant would benefit from repotting at about the point in time where the soil/root mass can be lifted from the pot intact - w/o the grow medium falling away from the roots. By that time, all the above factors will have been affected
..... or would it be better in a more roomy pot? How large a pot can or should be depends on the size of your plant's existing root mass and your choice of grow medium. The more water-retentive your chosen grow medium is, the more critical pot choice becomes. The reciprocal of that statement is also true. The less water-retentive and more air porosity a soil has, the less concern there is about increasing pot size. I use grow media that allows me to water thoroughly at will with no concern I might over-water. Getting to the point where your grow medium works for you instead of against you is probably the largest single step forward a container gardener can take.
How large will it eventually get? Large up to 60 ft or more where it occurs naturally, but all you need to keep it compact is a pair of pruners.
Does it ever flower? Yes, and produces a chestnut-like fruit/nut
I am in zone 6A. Might this plant be hardy outdoors? No, but it would appreciate spending its summers outdoors ..... and will definitely show its appreciation for the extra/natural light and air movement.
You didn't mention fertilizer, an essential part of your plant's care regimen. Let me know if you need help in that area.
Al
