Dracaena deremensis 'Janet Craig' works hard. Nobody labels screencaps of TV shows according to what plants are in the background, which makes this difficult to prove to you, but I managed to find two pictures. The first is of D. deremensis 'Janet Craig' acting on the set of "The Office:"
Personally, I think the plant was doing more believable work in the second season (that picture is from season 3, episode 15), but you know how the acting often gets kind of self-indulgent when someone gets famous.
For the longest time, I have been confused about the difference between D. deremensis 'Janet Craig' and D. fragrans. The two look pretty similar, except that the latter is almost always sold as D. fragrans 'Massangeana,' which has a group of yellowish stripes across the middle third of the leaf (give or take). 'Janet Craig' has darker, solid green leaves. It doesn't matter, for all practical purposes, because the two need exactly the same care, but sometimes one wants to know.1 It turns out that the key is the leaf texture. Fragrans has flat leaves, 'Janet Craig' has leaves with lengthwise ridges. 'Janet Craig' is also usually shinier, but you can't always go by that because of leaf-shine products and dust and stuff like that.
All of the D. deremensis group are solid members of the houseplant community: besides 'Janet Craig,' there are also 'Limelight' (which looks like a chartreuse 'Janet Craig,' and is awesome), 'Warneckei' (which looks like a 'Janet Craig' with lengthwise white and gray stripes), and 'Lemon-Lime' (which looks like 'Warneckei' with chartreuse margins). There's also 'Janet Craig Compacta,' which is, as the name suggests, a more compact version, both shorter and with shorter leaves, and I have a plant that is shaped like a 'Janet Craig Compacta' but has the coloration of a 'Warneckei,' which I'm assuming is called 'Warneckei Compacta,' but I haven't actually seen that name anywhere. (UPDATE: I think "Warneckei Compacta" is probably 'Jade Jewel.')
I'll be focusing on all or most of these at some point or another, but you may as well know now that they're all closely related, because there's going to be a quiz.
The reason D. deremensis 'Janet Craig' is so common is that it is very easy to take care of, and is pretty long-lived, which naturally leads to a lot of them being bought and sold and surviving indoors for long periods of time. They're one of those plants that do best when you're only kind of half aware that it's around. They can be damaged by extreme temperatures: don't leave them above 90F (32C) or below 55F (13C) for long periods. They are also supposed to develop burned leaf tips and margins in response to fluoridated water and underwatering, though I can't say I've seen this personally. The surest way to kill one, if you're wanting to kill one2, is to overwater it, though even then you may have to work at it, or at least put it in a pot that's way too large.
The catch to their relative indestructibility is that they're also not fast growers, so you should buy a plant that's at or just below the size you want.
Dracaena deremensis 'Janet Craig' is not easily propagated inside, though that isn't to say that it can't be done. Air-layering is traditional, though I would be surprised if you couldn't get away with chopping the top clean off and rooting the cutting in water.3 The cane left behind should, given enough time, sprout two new growing tips, plus or minus one, though until new growth is fully underway you need to be really, really conservative about watering, lest you rot out the cane. Segments of cane can also sprout if placed in damp soil, though Dracaenas haven't been as willing to do this for me as Yuccas and Dieffenbachias: so far, the canes just rot. I don't know what I'm doing wrong, but I should have material from work to practice with from time to time, so I'll get it eventually.
If your plant starts growing narrower and narrower leaves over time, this is an indication that it's not getting enough light, or is being kept too wet. It'll stay alive that way, but the leaves will broaden if you move it closer to a window and let it dry more. I have not personally found humidity to be much of an issue, though the books advise at least 40% (which is on the dry side of normal). So don't put this plant right next to heating vents or units.4 To minimize fluoride content, just in case that really is a big deal, minimize the amount of perlite in your soil mix (perlite contains some fluoride) or else flush the soil out with large amounts of water on a regular basis.
One odd thing that happens sometimes with 'Janet Craig' is that the new growth starts coming in yellow with green veins. This could be the result of iron deficiency, but also happens when the plant is being grown in conditions which are too hot – we had a couple 'Janet Craig Compacta' do this over the summer, and I recused a 'Warneckei' from work that had done this as well. These plants have difficulty making enough chlorophyll when the leaves are too hot. If it happens, add chelated iron according to the manufacturer's directions, and/or move the plant into a cooler spot; the yellow color may not disappear entirely, but new growth, at least, should come in more normally.
I don't actually have a 'Janet Craig' at home right now (I do have a 'Limelight,' 'Jade Jewel,' two 'Warneckei,' and a 'Lemon-Lime.'). We just got a big order of tropicals (it came in on October 18), and there were some 'Janet Craigs' in there, and they look nice, so I'm tempted, but realistically – there's not room, or money, and I shouldn't even be thinking about it. I would like to get one eventually, though; I've been increasingly impressed with Dracaenas over the last couple years, and I've always thought 'Janet Craig' was pretty, never mind the plain coloring and the fact that there's already one everywhere I go.
If I know me, I'll probably resist for a week or two and then get one anyway. *sigh*
"The Office" screencap was from here.
"Buffy the Vampire Slayer" screencap from Screencap Paradise. Used by permission.
Plant picture courtesy of the mysterious anonymous plant picture donor at Garden Web
3 Air-layering seems like a propagation method of last resort, to me. Maybe I'm wrong. I know I'm impatient, at least, if not wrong.
4 In fact, don't put any of your plants right next to sources of hot or cold air. None of them will like it.