It probably would be best to repot it. They usually come that way. It may droop a little after repotting, some do that as they may be in shock due to new home, new pot etc. You want no more than 1 inch or so between outside of rootball and inside of pot, so yeah only go up one size. It will grow as high was you let it. Some put in hanging pots and let them hang or climb curtain rods etc. They will climb just about anything. Use a well draining potting soil and a pot that has holes in bottom with a tray to catch excess. Just remember to drain the excess. Most houseplants are killed by overwatering. You have bought one of the easiest to grow. Feed it a light fertilizer every 3 months and it give it lots of light, keep the soil somewhat moist but not wet and it should stay happy. These also grow very well in offices with flourescent lighting. I have seen these vines be 30+ feet.

John and Mike are both excellent Meyer Growers....! Sunnyside, don't go with the 7-5-6. If you can't find Foliage Pro (check a hydroponic shop), you can use Miracle Grow with the same ratio - 24-8-16. The issue you'll have with the main commercial fertilizers is that they lack micronutrients, as well as appropriate Calcium and Magnesium. The way to know if the plant needs a larger pot is to judge by the amount of root-congestion. However, I am of the opinion that a 3 foot tree is too big for a 1-gallon container. Bump it up to a 2 or 3-gallon container, or larger if you can ensure that your soil-mix is fast-draining. I think I would play it safe and only go up a gallon or two, since you're in zone 5 and have the whole winter ahead of you. Aim for a mix that dries out between 2 - 4 days to maximize aeration. For the next few months, you'll be fertilizing *lightly* - as we near Spring, a heavier dose is recommended. Josh

As Rhizo said, not all soils are airless when moist, and overwatering is not much of a risk. Roots need oxygen & moisture at the same time to function. Overwatering isn't about how much water is added, it's about whether or not the excess is able to drain out of the pot and then how much air the soil has when saturated. Unless they are cacti/some types of succulents, drying out is stressful to most house plants, and unnecessary if the soil has plenty of air in it when moist. Sips are never good for leafy tropicals, but saturating the soil with a forceful gush of water can seriously compact the soil. When potting plants, don't pack the soil tightly, and water gently at least the first few times so the force of poured/gushing water doesn't compact soil, until the particles settle into a position, hopefully with plenty of tiny air spaces in it. At a sink or shower, slowly, gently add enough water over the entire surface so it runs copiously out of the holes in the bottom. When it's finished dripping, put it back in its' normal spot. If you think your soil is already compacted, you can use a stick or fork to poke down into it & pry up around a few places, to get some air back in there. Also assuming peaty potting soil, I think the key to Plant Lady's anecdote is that she tends to be an ignorer, not overwaterer. But she didn't say, and may be adding lots of perlite to it, making something of her own, or following a recipe. I totally agree with the part about putting multiple plants in large pots. Since I've started doing that, the results have been very good, for both me (time/frequency of watering) and the plants.

When you repotted, did you see the roots on the small plant? The wilting sounds like it doesn't have a large enough root system to support the number of leaves on the plant. If bagging helps, you'll have to leave it in there until it develops a bigger root system. If you can get that plant back out of the pot without too much fuss, you could put it in a glass of water to revive and form more roots. It also might be easier to bag this small plant in it's own pot rather than the whole bigger pot with both plants. Dave could be right regarding the very crunchy mix with orchid bark, it might not be retaining enough water to support the weak plant. I think strong plants would adapt to the mix you've used, if it was mine I'd just separate the little one and deal with it separately. Let us know what you decide to do, and if bagging the pot helps to plump the little plant back up. Dave, that's a great close-up of your bark, it looks much like the pine bark mulch I'm getting from Walmart. But 'The Water Saver' pine bark by Fafard I get from a wholesale nursery is finer, I think. If I can get a closeup pic of both I'll send to you for comparison with what you have. Russ