There's nothing particularly hard-to-please about the Strelitzia clan. Quite the contrary, actually. So, I'm not going after "queen" in the "off with their heads!" / "we-are-not-amused" sense. Nevertheless, it makes some kind of intuitive sense to me to call them King and Queen, if for no other reason than because they are capable of getting so huge, so imposing, even while still relatively young plants. Whatever room you put a Strelitzia in, S. nicolai in particular, the room is going to kind of belong to them. These are not plants that are going to blend into the wall, off in a corner somewhere: these are plants that you bring inside to make a Statement, the Statement in question usually being a very high-volume "THIS IS A TROPICAL ROOM! VERY, VERY TROPICAL!"
There are other reasons for these two to be houseplant royalty. For one thing, S. reginae's got a provenance and pedigree, in the way that most indoor plants don't. With S. reginae, we know exactly when she arrived in European civilization,1 and for what reason: this is hard information to track down, for a lot of plants. In this case, Strelitzia reginae was brought to England from South Africa in 1773, as part of a group of horticultural specimens for George III's Royal Botanical Garden. And then it was duly named for the queen, twice: reginae for "queen," and Strelitzia referring to Mecklenburg-Strelitz, the ancestral home of Queen Charlotte, George III's wife.2
There's no obvious reason why this particular plant should be named for this particular person, though I imagine I can see a little bit of a resemblance: maybe a close-up of Charlotte with googly eyes will help?3
The story behind S. nicolai isn't quite as solid, historically, but it was named for Czar Nicholas I of Russia. Couldn't dig up any particular reason for this; it's not like Nicholas collected the plants himself or anything. However, somewhere in the big tangled inbred mess that is European Royal Familial Relationships ca. 1800 (not one of my all-time best Jeopardy categories), there's an answer, I think. It's not really important, and I am also struggling with a rhinoviral brain fog as I try to write this so I'm a little confused, but if you're looking for a puzzle, see footnote.4 In any case, there was enough of a relationship to name this other species after Nicholas, so, nicolai.
I know, like you even care, right?
Strelitzia reginae is grown both for flowers and for foliage; the flowers are actually farmed in places with favorable climates. My husband worked on a flower farm in Hawaii during his misspent youth, chopping down blooms of Strelitzia reginae among other things (I'm told mostly Heliconia). This was apparently not all that interesting of a process, though: no amusing Strelitzia-related anecdotes or anything.5
Indoors, your Strelitzia is not likely to flower. I won't doubt readers who tell me that they had one flower indoors, if anybody wants to – it's just that a plant needs to be of a certain size and age, and it needs to be in very good conditions, especially bright light, in order to flower. This is all kind of tough to do inside, but summering the plant outdoors will definitely increase your chances. (Remember not to shock the plant by throwing it directly into full sun: as with any plant, the leaves will burn if the increase in light isn't gradual.) Any plant which does flower is, at least theoretically, capable of continuing for several months: plants can bloom at any time of year, and individual flowers are long-lasting.
But the leaves are nice on their own. I'm a sucker for all kinds of plants, but there's a big subcategory of plants I fall for particularly hard: the guys with big, ovalish leaves. Strelitzia nicolai is the current record-holder for the biggest leaf in the apartment: 27 inches long and 10 inches wide, roughly 68.5 cm by 25.3 cm. And I've seen bigger than that, actually, just not on my own plant.
Most of the Strelitzia spp. sold as potted plants in Iowa City (as best as I can tell) are nicolai, not reginae, though if you want a flower, it will probably wind up being reginae and not nicolai. We have both species for sale at work as potted plants: I haven't asked the flower shop whether they ever get white bird of paradise flowers in, but so far I haven't seen any. I'd be surprised if there was much of a demand. I've been asked for one or the other species before, and this has been awkward, because until I started researching for this post I wasn't clear on how to tell the two apart, but I think I've got it now:
S. nicolai gets very large, on all counts: the flowers are larger, the leaves are greener, shinier, longer and broader, and the plant itself gets to about 30 feet (9 m) tall. The flowers are also white-and-blue. Representative S. nicolai photo here. S. reginae, on the other hand, has grayer, duller leaves, sometimes with a slight orange tint along the midrib. The leaves are proportionally narrower than those of S. nicolai, and are a little heavier and stiffer. The flowers of S. reginae are orange and blue (though there is at least one variety called 'Mandela's Gold' which is yellow and blue: picture here). S. reginae grows to about 5 or 6 feet tall (1.5-1.8 m) and then starts growing horizontally instead; it's unusual for one to offset indoors, but outdoors, offsets form relatively freely, leading to clumps that are about 5 or 6 feet across, as well as 5 to 6 feet tall. Sample photo for S. reginae here.6
S. reginae is probably the better long-term indoor plant: however old it gets, it should still be able to fit under your ceiling. S. nicolai will eventually get too big, and I doubt that you can cut them back without killing the plant. Indoors, though, that's not likely to happen fast, so you might be able to grow nicolai inside and defer the problems of a too-large plant to your home's next occupant, or your children, or somebody.
There are at least four other Strelitzia species, according to Wikipedia and davesgarden.com combined (alba, caudata, juncea, parvifolia: Wikipedia leaves out parvifolia), though none of them appear to be widely available. S. juncea (picture) is particularly interesting to me: it looks like a reginae with petioles but no leaves. The overall appearance, at least in pictures, is of a large, coarse grass that for some reason grows bird of paradise flowers. S. alba resembles S. nicolai strongly, and also has white flowers, but the flowers are apparently structured somewhat differently. If the flower you're looking at has a single spathe (the strong, horizontal part, either green or blue, from which the rest of the flower emerges), with multiple flowers arising from that spathe, then it could be either species. If the flower has multiple spathes emerging from one another in a "triple-decker" kind of structure, and multiple flowers emerging from each spathe in turn, then it's a nicolai. This is according to one person's post at Garden Web, and I have no way to verify it, but it does kind of sound right. If this is in fact the way one tells the difference, then davesgarden.com has pictures of nicolai in the photo sets for alba. The odds are strongly in favor of any very large greenish NOID Strelitzia being a nicolai: alba seems to be rarer both in cultivation and in the wild.
I think the reason why there are more nicolai than reginae plants sold here is because in this climate, you're not likely to get the flowers no matter what you do, so people are growing the plants for the foliage, which means leaves, which means that the species with bigger, more impressive leaves has the edge. I would guess that the situation is reversed in the south, but I don't really know: I wasn't aware of the difference between species when I actually lived in South Texas as a kid. (Any Southerners want to share?)
I had a reginae at one point when I was in high school, and it didn't do well, which was most likely my fault but I have no idea what the specifics of that case might have been. It's been too long ago. So I can't give you a head-to-head comparison between the two species, though I'm under the impression that the care should be more or less the same for both, and for what it's worth, the nicolai I have at the moment have been awesome as far as care goes. So let's get to care:
Light: My own plants are in a west window, and have been fine with this for quite a while. Initially I tried a south window, which probably could have worked, but I had trouble watering often enough to keep them happy there. The ones at work get filtered sun more or less all day, year-round, and seem happy enough with that. I would not try growing Strelitzia in a room which got no sun at all, however bright the light in the room was.
Water: Plants that are too dry will let their lowest leaves yellow and drop; I have yet to see what happens to plants that are too wet (but see Feeding). As a general rule, I don't let mine dry out beyond the top couple inches of soil, and they seem to like that just fine, regardless of pot size.
Humidity, Temperature: Surprisingly, Strelitzia are quite lenient on both counts. I've had the largest of my plants sitting in a spot right under a heat / air-conditioning vent, and it hasn't complained at all about the dry air or the weird temperature changes. This is good, since that was pretty much the only place in the apartment left that had enough room and light for the plant. That said, they are supposed to like additional humidity. I see conflicting information on temperatures, but it looks like it takes fairly serious cold to kill a Strelitzia (in the neighborhood of 20ºF / -7ºC). They can handle the occasional light freeze, albeit with some cosmetic damage to flowers and leaves. So even playing it on the cautious side, and leaving a plant out unless the temperature is supposed to be below, say, 45ºF (7ºC), should be fine, though I'd probably be even more cautious with my plants, and not go below 55ºF (10ºC), for fear of stressing it or slowing its growth down. I suppose I should note here that if you move your plant in and out a lot, and leave it outside on windy days, the leaves are going to catch the wind and tear: while this is perfectly normal and natural, some people don't like the way it looks.
Grooming: Virtually non-existent; pretty much limited to pulling a dead leaf off every six months or so. Some dusting, too, I guess. Repotting is a bit contentious: they're said to bloom better if their roots are cramped. This may be, but their roots are also monstrous, so even if you're aiming to keep them cramped, you may still find yourself needing to repot every year or two.
Feeding: There's also considerable disagreement on this count: the growers' guide says they're not heavy feeders (though they like calcium), and can be damaged by too high a level of soluble salts in the soil, but some of the on-line sites that turned up said they need to be fed all the time. In the lower-light conditions indoors, I suspect that less food is probably better. The growers' guide does mention that in conditions of very iron-poor soil, very soggy soil, or soil which has broken down and compacted around roots, plants may show signs of chlorosis: if new growth is coming in yellow, consider adding some iron, easing back on the water, replacing the soil, or some combination of these.
Pests: Neither my plants at home, nor the plants at work, seem to have any particular susceptibilities to pests, though I think I've seen the occasional spider mite or two. It's always worthwhile to keep an eye out for scale and mealybugs, but I haven't seen anything to make me think that those are particularly likely.
Propagation: Strelitzia spp. can be propagated from seeds or from offsets, and there are big problems with both. Offsets are problems because you only get one when the plant decides it wants to make one, and as far as I know there's no way to speed that process along. Seeds you can buy whenever you like (as for example from seedman.com, which offers 5 seeds of Strelitzia nicolai for $2.50, plus shipping and all that.), but you'll still have to wait: they're slow to germinate. One site said up to eighteen months (!) to germinate, another site said they should only take four to eight weeks. As the latter site was actually from Africa, where one would assume that the seeds are fresher and the climate more suitable, my guess is that four weeks would be lightning-fast, for an indoor grower. (One does not rush the king into doing anything.) On the plus side, both sites seemed fairly positive that seeds eventually would sprout: it's just a question of when. In fairly ideal conditions, a seedling of S. reginae is ready to flower when it is about seven to ten years old.
As with Monstera deliciosa, when I first started buying Strelitzia nicolai, I got a little overenthusiastic, and soon wound up with four of different sizes (one huge, two 6-inch, one 4-inch), which is too many. These are great plants, but they're probably not plants you want to develop an obsession about, or start collecting, 'cause if you do you'll run out of room really fast. (And not only run out of room, but you can really only have just so many kings and queens together before you start getting all kinds of crazy palace intrigues. Best to keep the plots simple.) A single Strelitzia by itself in a well-chosen spot, though, can be great.
-Queen Charlotte painting via Wikipedia entry for Queen Charlotte. (Googly eyes added by yrs truly.)
-Both Strelitzia reginae pictures taken from the Wikipedia article on Strelitzia reginae.
-Strelitzia nicolai in the laundry room picture used by permission of an anonymous Garden Web photo donor.
1 Not that there's anything all that special about European civilization, not exactly. Other civilizations stuck around for a long time and had various cool things going on in them. But had Strelitzia reginae not been on that boat to England in 1773, there's a good chance I wouldn't be writing about it now. (Lest you think I'm some kind of hostage to political correctness for feeling the need to make that clear -- you know, so much of so-called political correctness is just about trying not to be an asshole. Seriously. I am completely mystified by the people who rant and rave about how unfair it is that they can't say the word [fill in misogynist, racist, homophobic, or etc. slur of your choice], how the Language Police are taking their right to free speech away in the name of Political Correctness, and it's so hard to be [some combination of: white, male, straight, wealthy] these days. Why would you want to? What is the point of demanding the right to say words that are hurtful to complete strangers? How do you benefit? Maybe everything is not about you. When I say Europe wasn't the only game in town, civilization-wise, I'm mainly just trying to acknowledge that, you know, it wasn't, and incidentally I'm trying not to be an asshole who thinks the whole world revolves around me and my particular culture. Because it doesn't. I don't feel like I've phrased this especially well, but I'll let it stand anyway.)
2 Being Queen of England is a good way to get stuff named after you, though not as good as being King: Charlotte, North Carolina, was named for her, as were two counties in Virginia and one in North Carolina (Charlotte, Mecklenberg, and Mecklenberg, respectively); Charlottetown, Prince Edward Island, Canada; Queensbury, New York; the Queen Charlotte Islands of British Columbia, Canada; and so on. Being King, on the other hand, will get you Georgetowns all over the place. Americans tend not to be terribly fond of George III, as he was the monarch in charge of England when we revolted; I couldn't really get a sense from reading around whether he's really all that terrible. As British monarchs go, he seems to be mostly notable for being a faithful husband (no, seriously!) and for going crazy near the end of his reign (due to porphyria). The mental decline is dramatized in the movie The Madness of King George: I saw it a long, long time ago in a mostly-empty arthouse theater in Houston, TX, with my best friend and his then-girlfriend, and I think I liked it but I really, frankly, don't remember anything about it beyond the obvious: there was a king named George, and he went mad. Also there was something about a chamberpot and funny-colored urine, which is less obvious. But I digress.
4 Ummkay. So Nicholas I of Russia married Charlotte of Prussia, who subsequently, for reasons I didn't care to investigate, changed her name to Alexandra. Maybe Nicholas already had the bath towels monogrammed for someone else or something. Charlotte/Alexandra was the daughter of Frederick William III of Prussia and Louise of Mecklenberg-Strelitz. Louise's aunt was Queen Charlotte of England. So the relationship between Charlotte and Nicholas is, Charlotte was the aunt of Nicholas's mother-in-law. Which really muddies more up than it clarifies: they weren't particularly related to one another, were they? So why? I do not know.
5 Heliconia was apparently more memorable: he says they used to kind of suck, because rain or dew or whatever would collect overnight in the flowers, and then when you cut the stems the water would fall all over. Also sometimes there were mosquitoes.
6 Just FYI: I figured all this out after naming and saving the pictures, so those pictures in this post which are mine all have file names referring to reginae even though they are, I think, actually all nicolai.