I would do a carnivorous terrarium and add some pitcher plants in the center and some sundews on the sides.

Thanks for the suggestion! :)

I would love to do something like this: http://www.etsy.com/listing/100309845/apothecary-jar-terrarium-twisted-with

Does anyone know what that is exactly?

It looks like one of those bonsai money trees. That is going to require alot of pruning.

I'm interested in getting into bonsai, as well, so I'm ok with that. :) I'm just not knowledgeable in it enough yet to be able to recognize most species used for bonsai, except for weeping fig.

The biggest question is how long do you want whatever planting you do to last?

Two main approaches:
1)Temporary/Ephemeral: If you don't mind redoing it every month or so, the possibilities are vast. (In that regard you would be treating this not unlike a cut flower arrangement ... and there is nothing wrong with that if that is what one wants.)

2) Lasting/Longterm:If you want something more "permanent", your options are much more limited -- and the more "permanence" you desire, the more limited your options. A Longterm planting is far more problematic/challenging than one that is Ephemeral.

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*NOTE: Do keep in mind that the following comments are not meant to "pop your bubble" but rather are intended to educate and help you avoid aggravation.
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FIRST AND FOREMOST, if you are thinking Longterm, do not go hog wild with putting lots of plants in that jar. Always use less than you think you will need. It may look 'anemic' for a little while, but once the plants settle in and get growing, you will be amazed at how fast a terr can go from 'thin' to 'waaaaay over crowded'.

If Longterm, don't even toy with the idea of succulents or cacti -- it would only lead to dead plants & heartbreak.

A set-up like the one you URLed would be unlikely to last long and would, I suspect, be rather high maintenance. As GTD mentioned, pruning would be required -- including root pruning. (Btw, the tree in that picture is probably Ficus benjamina.) Lack of air circulation would be an issue. Unless you are looking at this from the Ephemeral viewpoint, forget bonsai or any type of tree/shrub for that matter. They do not make good terrarium plants. Lack of air circulation and poor lighting is always problematic for them.

Scratch the pitcher idea if planning on Longterm -- Sarrs do not stay small long in decent condtions and quickly grow out as well as in the vertical. Getting a large one out of that jar would be a pain and trying to remove dead pitchers would be an absolute nightmare in that jar. In addition, as it grew outward, it would quickly crowd out any dews.

Forget the Drosera (sundews) as well unless you restrict yourself to the mini or dwarf growers if you are thinking Longterm. The larger growers (both in height and width) will plaster their sticky leaves against the glass. Not only does this make a mess, but the leaves involved tend to rot out/get slimy quickly at those contact areas. Also, removing dead leaves will be a royal B in that jar no matter what type of Dros you do. (Unless of course you don't mind the dead/browned out leaves -- some folks don't. In which case that is one headache you would not have to worry about.)

Most plants that would do well in there will very quickly fill the container so do be prepared for regular pruning/weeding maintenance if going Longterm.

That said, you would do best to seek out mini's -- plants that stay very small. Not the easiest things to find truthfully. Many of the terrarium plants sold look great initially but then quickly get far bigger than what one may want. One of the best mini's that actually stays a mini (maxing out at about 3-4 inches tall), IMO, is Epipremnum 'Pincushion'. Unfortunately it is not very commonly offered. You can find a link to a picture of that (as well as a few other plants) at the bottom of this post. Go down to the last two shots in the bottom right. (This is a page of plants I sell divisions of from time to time, in case you are wondering.)

A mini african violet (a true mini, not merely a young plant) could do well in there for a fairly long time. (Many mini's tend to sucker so that over time they will form a mass that needs to be chopped back.)

For the height of that vase, I would suggest finding an attractive piece of driftwood to stand in the back. You likely would need to seal the wood first though to avoid it molding.

Beware of ferns. Though these mild mannered looking plants do look nice in a terr, ferns will quickly outgrow just about any terr. One of the few groups of plants with a number of members that seems to love humid, stagnant conditions. Also the slimy leaf problem mentioned with Drosera is true with ferns as well.

Cryptanthus would be one I would recommend. There are some very small growing varieties out there as well as some that would get too large for your container.

Also, there are types of bromeliads that will stay very small. HOWEVER, most do require decent aircirculation and most (though there are exceptions) could not be planted in the substrate -- you would have to have them mounted, perhaps on a piece of driftwood or rock.

Most species of Selaginella would quickly run amok in such a container, but Selaginella kraussiana var. brownii is one type that tends to be well behaved.

Here is a link that might be useful: Epipremnum and others

Wow! Thank you for the in depth response! I'm ok with pruning and such. I very much enjoy that portion of plant ownership. I was really only planning on something that might have a little height, and something low to the ground, maybe even just some sort of moss. I'd like ti to be long term. I hadn't thought of the idea of mounting something to driftwood -- that could give me the height I need without having a plant that is actually somewhat tall (for a terrarium) and narrow. I'm heading out the door right now, but I'm definitely going to look into all your information in more depth later! Thank you again!~