Monday, August 31, 2009

Air Traffic Controller (Streptocarpus cvv.), Part I

I don't actually swear off plants all that often. True, there have been a few that pushed me too far, but generally I'm optimistic enough that I stop short of ruling a plant out forever and ever. Originally, when I started writing this, Streptocarpus was going on the list too.


Compared to others on the list, it's not that bad, really. It's not especially buggy, like Hedera helix or Codiaeum variegatum, and it's not perpetually miserable like Philodendron 'Xanadu,' or a dramatic and heartbreaking failure like Calathea ornata. I've just never had a good experience with one, either at home or at work. Or, well, I had one good experience, with one individual plant. It lasted about two months. Then it turned into another bad experience.

My first experience with Streptocarpus was in the fall of 2007, right after starting the greenhouse job. Apparently people here treat streps like annuals and keep them outside, and then pitch them in the fall. Or that was the theory: I've been watching, but have yet to see anybody with one on their front porch or planted in a flower bed. Who knows what they're doing with them really. Nevertheless: if they come in, they come in in the spring.1 And in August 2007 when I started, there were still a lot of those left over from the spring, on the east side of the building, getting cooked in the morning August sun. Which was kind of dumb, because they don't like direct August sun. (I never claimed we were smart.2)

So we brought them into the greenhouse (looking back at it now, this was probably a bad call: however hot the east side of the building got, the greenhouse got hotter), and then I noticed that some of them had mealybugs. So we pulled them out of the greenhouse into the back room, and squished the visible bugs, and sprayed all kinds of crap on the leaves to kill the invisible bugs. Which left big ugly black spots on the leaves. Not helpful. And the mealybugs persisted anyway, so we were scarring the leaves for nothing. So they got dumped. I don't know how many we threw out. It seemed like a lot at the time.

And then I didn't see any Streptocarpus again until the spring of 2008. We got a bunch of plugs in, and potted them up, and although a few rotted right away, that was fine: we had plenty. And when they started blooming, I thought they were pretty. So I picked out a nice one, all loaded up with buds, of a red-pink variety called 'Tanager,' and took it home. Whereupon it immediately dropped all of its buds and then sat there, sulking, for about six months, doing absolutely nothing.


The plants that stayed behind at work weren't doing any better: the greenhouse got hot, so we moved them outside, and then it rained, and rained, and rained, and flooded, so all of them rotted and died as a result.3

Meanwhile, around September, my 'Tanager' at home suddenly started growing leaves again. Which was great. I mean, leaves aren't as good as flowers, but whatever. I was just thrilled it was doing something. And then come November, we had flowers too. It was great.

It was also temporary: that plant was dead by January 2009. It just kind of went limp one day and wouldn't come back.

So I tried again, in March, this time with the cultivar 'Purple Martin.'4 It didn't come to a complete stop once I got it home, like 'Tanager' had: it continued to grow leaves, and it even flowered once or twice.

And then it all went limp at once and wouldn't revive when watered and it was dead by June. I lost a lot of plants between May and June, because we moved to a new house and everything was chaotic, including waterings, but still.5


So I've seen Streptocarpus die in all kinds of interesting and unexpected ways, and I'm not a fan, and I don't recommend giving them to anybody unless you're trying to break down their self-esteem or something.6 I'm not willing to rule them out entirely, because in the process of writing this profile I've seen some pictures of some really ohmygod beautiful ones, and for the right plant, I might be willing to try again. But we'd have to be talkin' about one charming motherfucking pig Streptocarpus.

But enough about me. You're probably here because you want to know how to care for them, right? Crap. Um. . . .

The other websites make them sound easy enough. Basically like African violets, but easier, is the impression I get from reading around. Here's the general consensus from the net, with particular attention given to places like streptocarpus-info.com and robsviolets.com,7 which are trying very hard to give the impression that they know what they're doing, and maybe actually do:

LIGHT: Bright light, with some sun, appears to be ideal, as for example an east or west window. Too much sun will burn the leaves, and they won't flower if they're not getting enough light. One way around both problems is to grow them under fluorescent lights: like African violets, Streptocarpus do well in artificial light.


WATERING: Supposedly, Streptocarpus do best if allowed to dry out between thorough waterings, even to the point of going a little limp (like for Spathiphyllum), though they should never be allowed to stand in water or dry out completely. This is more or less the way I water all of my plants, with a few exceptions, so you'd think I would have been able to manage this, but no. It's also not as simple as that, because as with most other gesneriad species, if you get cold water on the leaves, the leaves will develop spots. (You can bottom-water to get around that, or just use room-temperature water.)

The bigger issue, though, seems to be with soil quality: Streptocarpus must have an extremely light and porous soil or they will develop root rot. (This is my best guess for what went wrong with my plants.) The exact composition varies depending on who is doing the recommending, but both streptocarpus-info.com and robsviolets.com advise a minimum of 50% perlite.


Plants are best in wide, shallow pots than in tall, skinny ones. Azalea pots (which are 3/4 as tall as they are wide) are usually what is recommended, though this is more of a gentle recommendation than a hard and fast rule. The boss's mother at the greenhouse had her plants in pots that were deeper than they were wide, and they were the most amazing Streptocarpus I'd ever seen.

A number of sites repeat the same advice over and over, to water the plant when the top 1/2 inch of soil is dry. My advice would be, don't rely too much on that as a guideline, because the moisture level in that top half inch will indicate very different things in dense, wet soil than it will in light, airy soil. Waiting to see the leaves go slightly limp seems more reliable to me.8

HUMIDITY: Humidity levels have a large influence on certain other aspects of care, more so than with a lot of other genera of houseplant. If the plant is in high humidity, it can take more direct sun, and for a longer period, than a plant which is in low-humidity air. They are also more tolerant of underwatering and high temperatures if the air is moist. As a general rule, more humidity is better, the one exception being that tightly crowded plants in high humidity are prone to rot and fungus. So don't increase humidity at the expense of air circulation.

TEMPERATURE: Everybody is in agreement that Streptocarpus do best in a cool room. Definitely keep the temperature below 80F (27C) as much as possible, and aim for somewhere in the range between 55-75F (13-24C). I can more or less vouch for this personally: in the greenhouse, our plants did well if they were near the doors (where they occasionally got cool air) and began to droop and look miserable at about the same temperatures I did.9


PESTS: Mealybugs are the only ones I've seen personally, and appear to be the most common problem, though thrips and mites, I'm told, can also affect Streptocarpus. None of the sites I ran into seemed to really emphasize pests as an issue, though, so I expect that cultural issues are the main cause of death. (I should be so lucky, to keep a strep alive long enough for it to get bugs.)

PROPAGATION: I've never managed to make this work out, either, but supposedly these can be propagated much like Saintpaulia or Begonia. The usual recommendation is to take a long, healthy, middle-aged leaf, and make two parallel lengthwise cuts, one just above the midrib and one just below, and then plant the leaves in moist potting soil or vermiculite, with the cut edges in the soil and the original leaf margins sticking up. In theory, this is supposed to result in new plantlets forming at every vein along the cut leaf.

One is also supposed to be able to cut leaves into chevron-shaped sections and plant those in potting soil or vermiculite, and get new plants that way. I've tried both of these methods and neither of them resulted in new plants, though in fairness propagation wasn't really a priority and I wasn't paying terribly careful attention to the conditions. Wedge cuttings are supposed to be more reliable, but the cut-out-the-midrib method is (theoretically) capable of producing more plants, total.


Sticking leaf sections into shallow water, provided that one has a way of keeping them upright, might also be effective, according to this thread at Garden Web. Cutting out the midribs, wrapping the resulting half-leaves in damp paper towels, and enclosing the paper towels in a Ziploc bag, instead of planting them in vermiculite, is also said to work. I've not tried either of these methods at all.

Plants may also be grown from seeds. The seed pods are long, thin, and twisted brown things which are occasionally seen on plants in retail situations. (I saw them at work a time or two; I don't know why I didn't get a picture but I'm sure I must have had a very, very good reason.) I have never seen the seeds directly, but they are supposed to be extremely small, and should sprout under more or less the same conditions as fern spores: fill one side of a clear clamshell-type container with damp vermiculite, sprinkle seeds over the top, don't cover the seeds, close the container and leave it in a bright spot until seeds begin to germinate. I don't know of any vendors who sell Streptocarpus seeds, but I'm sure there must be some out there somewhere.


One may also divide mature plants with multiple crowns; this has the advantage of providing you, in theory, with new plants that already have root systems, but the disadvantage is that it will make you feel like a big, lumbering brute who destroys anything s/he touches, as the stems, leaves, and roots are all very fragile. The plants don't necessarily care about this, though, and divisions will happily re-root in a bright, humid environment even if you didn't manage to retain any roots while dividing.

GROOMING: Grooming is actually kind of a bigger pain than I'd originally thought. Particularly in low humidity, leaves will develop brown edges and tips, which don't really hurt anything but which people generally cut off anyway. Also dead flowers need to be cleared out regularly, if you're lucky enough to get flowers, because otherwise they can begin to rot, which may lead to healthy leaves. These are not especially big issues. But:

Plants also fill their pots with roots very rapidly, in the improbable event that they're happy with you, which means that repotting and/or dividing is necessary for proper maintenance. Exactly how often this needs to happen will vary, but most of the sites I looked at that mentioned this said either every six to twelve months. That's a lot of repotting. The typical recommendation seems to be to move plants up to larger pots until they hit a 5-6" pot, and then divide plants and keep putting them back in 5-6" pots thereafter. I don't know what happens if you keep moving up to larger and larger pots. Probably they die. Dying seems to be a skill. At work, we did plant up some hanging baskets with four plugs to a ten-inch hanging basket -- some of these did fine, though what usually happened was that one or two of the plants would die, leaving the basket lopsided. A ten-inch hanging basket in which all four plants survived, particularly when all four are blooming, is definitely pretty, though, so I sort of understand going to the trouble anyway, even if it rarely worked out well enough to justify the work.


Flushing soil out with water from time to time is also sort of a big deal, apparently, though I'm a little surprised by this because it seems like you wouldn't have the plant in the same soil long enough for fertilizer salts to build up to the point of being a problem. Apparently not, though.

FEEDING: The people who are serious about growing streps recommend a high-phosphorous fertilizer from spring until fall, and then either no or very little fertilizer from fall to spring. The precise formulation doesn't seem to be particularly important: I saw recommendations for 7-9-5 and 10-30-10.10

The "person" to go along with Streptocarpus, air traffic controller, wasn't chosen because air traffic controllers sit around all day doing nothing at all, then suddenly fly into a panic and collapse, like the plant does. (At least, your better air traffic controllers don't.)

On the contrary, real air traffic controllers have to be unusually calm, and able to keep a clear head in stressful situations, and it's a difficult job to get in part because there are tests in place to weed out the people who are likely to fly into a panic and collapse. So the temperament could hardly be more wrong for this plant. However: Streptocarpus are actually one of the better houseplant examples of the phenomenon of "nectar guides," which does work as an air traffic controller reference (or at the very least it's close enough for PATSP). We'll pick up on Thursday with a discussion of what nectar guides are and why they matter. Jokes and light refreshments will be provided. Those of you who already know about nectar guides, please try not to spoil it for everybody else.

-
Photo credits: all my own except for the Streptocarpus fruit picture, which came from LucaLuca via Wikipedia. I would have liked to include pictures of other varieties, but I've only ever directly encountered four ('Tanager,' 'Purple Martin,' 'Falling Stars,' 'Snow Bunting'), one of which ('Snow Bunting') photographs badly, and I couldn't find public domain / Creative Commons pictures I liked. There will be a picture of 'Falling Stars' in Part II.

1 For the spring of 2009, we'd ordered them again, but they didn't arrive when they were supposed to, nor did anyone at our supplier seem to know where they were, and our supplier was actually buying them from someone else, and they (our supplier) couldn't contact anybody at the other place. In the end, we had to just assume that the other place had been a victim of the crappy economy and had gone out of business. We didn't have to pay for the Streptocarpus plugs we didn't receive, but there was also no backup plan from the supplier, either. So we just didn't get plugs, period, see footnote 4.
2 (Or, if I did, I totally take it back.)
3 "All" might be an exaggeration: I don't remember whether there were any survivors. We lost the overwhelming majority of them, in any case, and none survived to the following spring, so one way or another, bad things happened to them.
4 Although the supplier didn't deliver any to us, we were able to get some from the boss's mother, who had some amazing, huge ones from the 2008 batch, or maybe earlier than that, which we divided. I hated dividing them: however careful I was trying to be, they were incredibly brittle, and they didn't break in particularly good spots, and I was sure when it was all over that I'd just butchered the hell out of her plants and killed them for no good reason, that nothing was going to be salvageable. I was overreacting, though, because the same percentage loss was about the same as we would have gotten from plugs. The 'Purple Martin' I bought was one of these divisions.
5 Worse, I think the streps were setting a bad example for the Saintpaulias, because around this time all of the Saintpaulias, which had previously been looking a little unhappy but were still basically functional, started falling to pieces as well.
6 If so, be advised: there are cheaper and more effective ways to do this than showering the person with difficult houseplants. Many people, I'm told, don't even care that much whether they can keep a plant alive or not.
7 Though robsviolets.com is immediately suspicious on account of saying things like "They are a great flowering houseplant for people without 'green thumbs.'" In my experience, there are no good flowering houseplants for people without "green thumbs," and if there were, Streptocarpus would definitely not be one of them. I should also note while I'm here that "like Saintpaulia, but easier" is backwards in my experience, which is reflected in the higher difficulty level for Streptocarpus. Your mileage may vary.
8 However: leaves will wilt when the plant is too wet or too dry. Spathiphyllums are like this too. So, don't just take the leaves' word for it that they're dry: check the top of the soil too, and the weight of the plant, before reaching for the watering can.
9 Although I hadn't really been particularly prone to heat exhaustion before the greenhouse job, I definitely was once I'd been there for a while. Although my psychiatrist told me it wasn't really known to cause heat sensitivity, I suspect now that the reason behind this is the wellbutrin I'm on for depression. It's possible that switching to a different medication might also handle my depression fine without the heat thing, but odds are I'd just have a different set of side effects to deal with, and those side effects might be worse, plus switching to a different medication might well not control the depression at all, which would definitely be worse. The heat thing was a good percentage of the reason I left the job, though there were lots of other reasons.
10 I also saw a recommendation for 10-10-10, which would probably work if you wanted it to, but it looks like you'd be throwing away a lot of the nitrogen and potassium that way.


18 comments:

Anonymous said...

I have a friend who has the most amazing luck with these plants; he propagates them like mad using bits and pieces, whole leaves, whatever. Our land trust was fortunate enough to get donations every year of 50 or more blooming specimens for our garden sale and we made a bundle on them. He gave no special treatment (in fact he tends to get distracted and neglect plants from time to time) except that he mixed his own fertilizers from the raw ingredients. I would cadge a plant on loan from time to time and despite my doting care it would go into decline and I would return it for nursing care. (In general I can't grow gesneriads or any hairy leaved plants because the gas contamination in the house from gas lights and appliances is death on them.)

I say to all, try them and see - a hugely blooming plant is such a sight that it would be worth the effort.

mr_subjunctive said...

If I were going to try again, I'd try keeping them in the basement under artificial light (where it's cooler, and humid), and I'd replace the soil with something more perlitey. It would be interesting to see whether that would help. I would have to draw the line at mixing my own fertilizers from hand, though, I think.

They are gorgeous when they're happy. No denying that.

Karen715 said...

My general experience with Streps are that they go along swimmingly for a while, then for no reason I can see, collapse and die. If (and that's a big if, since I find them more trouble than they are worth) I try them again, I'll have to up the perlite content of my medium.

Pinetree Garden Seeds (superseeds.com) sells Streptocarpus seed. They're a good company in my experience; I've purchase a fair amount of seed for my garden from them. Their seed packs tend to be small, but their prices are good, and the seeds have good germination rates.

Parks used to sell them, too, but I don't see them on their site right now.

mr_subjunctive said...

Karen 715:

I had a weird realization while writing this: other than the four varieties I've seen at work, I don't think I've seen any Streptocarpus for sale anywhere. Not at Lowe's, Wal-Mart, Earl May, Ace Hardware, Frontier, Pierson's, Peck's, Home Depot, Menards, the consignment store, grocery stores, or anyplace else I can think of that carries plants. Nobody carries Streptocarpus. (I've seen Streptocarpella once, at Pierson's.)

I can only think of a handful of other plants like that, that I've never seen outside of work. Maybe they should actually be higher than 7.1, if nobody is willing to carry them.

lynn'sgarden said...

Actually, Streps are common in our grocery stores' floral dept...usually in springtime. I add them,(who can resist that gorgeous deep purple shade?)along with mini daffs and tulips when making a countertop arrangement. They don't survive more than a month (for all those reasons you listed) so out they go with the finished bulbs. I've never seen them in a hanging basket format, though. And as easy as African Violets are supposed to be...I've not had luck with those either ;(

Anonymous said...

If you decide to try again, definitely try very porous soil. Streps are extremely easy plants for me, and I don't do anything special, except that all my plants are in porous soil -- either roughly the kind of soil that Al on Garden Web recommends, or 60/40 perlite/peat mix.

I've given away streps to people with very little to no plant-growing experience, and so far I think all of those plants have survived, and most still look excellent by my standards. I had to rescue one of my former plants after it was left sitting in water for weeks, but, well, few plants can be expected to do well in such conditions. And even that plant bounced back eventually, I guess decent soil saved it. So I agree with Rob's Violets that streps are great plants for beginners -- as long as the plant is in very porous soil, the person is given clear instructions, and is willing to pay some basic attention to watering. There is of course the issue of having to water often -- because, well, very fast-draining soil -- and that might not suite everyone.

I do have one variety that I can't grow well -- leaves keep getting brown spots, and buds keep drying up, even though it gets the same care as my other streps. It's quite a shame, because this strep is supposed to be very pretty. So it looks like there is some variability in care requirements between them, maybe you were unlucky and picked up one of the more difficult verities?

One thing though -- while I do see streps for sale in local small nurseries (not big box stores though), unless the plants were just delivered, they are always in poor shape, with centers starting to die. I'm fairly good at bringing half-dead plants back to life, but store-killed streps are somehow a special case, and of the 5 plants I bought locally, 3 died. And those are the only 3 streps I've ever killed. Maybe there is something about constantly wet all-peat soil that kills them just right. It's definitely easier for me to start a new plant from a leaf than to save a locally-bought full-grown streptocarpus that was sitting in the store for a while. I've always had good luck with starters I bought over the internet. So if you decide to try growing these guys again, maybe get a starter from someone who you are sure is growing them well? This way at least you are not doomed from the beginning, which sort of sucks.

mr_subjunctive said...

Hmm. We used the Ball mix at work for these, which is mostly composted bark (30% peat, IIRC) and generally drains well enough for my purposes, but then we planted the plugs directly into the 5-inch pots we wanted to sell them in, too, rather than start them small and repot a couple times, so maybe that was part of the problem. (Even so, we didn't lose very many plants until it started to get hot, and they never failed or thrived uniformly: there were always some doing well at any given moment, and some falling apart.)

As far as specific varieties being more or less difficult, I would have had to have picked up two difficult varieties, not just one, and neither of those were the most problematic at work: 'Snow Bunting' tended to rot and die a lot. 'Tanager' was more robust, and didn't die as easily, but it was also really reluctant to flower.

If I try them again, I'll try the porous soil thing, but they don't sound like something I'd be good at taking care of even with the different soil, and I've had bad experiences already, so that's a big if.

Diane said...

I am in the process of killing my first Streptocarpus right now. It did great and then one day went limp as noodles. I repotted it but it doesn't look good. Saintpaulia on the other hand thrives like crazy for me and I don't give it any special treatment. Maybe I should just buy a hundred violets and stop trying to diversify.

mr_subjunctive said...

I've got to say, this is making me feel a lot better about the whole thing. I figured I'd post that I'd killed two Streptocarpus and I'd be leapt upon by people telling me OMG, Streptocarpus are sooooooo easy, you must be an idiot to have killed one. But if everybody else does it too, then I don't feel nearly as terrible. And I've gotten tips for how not to kill future streps, if any. So a good day for Mr. Subjunctive, all in all.

Anonymous said...

Hey, I've killed my share of Streps too. One tip; when you transplant, leave the crown a little higher than you normally would; it helps prevent crown rot.

I seem to remember they grow on cliff sides in Africa, which would explain both their need for pH neutral soil and their propensity for root rot.

Korina

Lance said...

Only now catching up with my reading, and only slightly on topic. I'm glad to hear of someone else with heat problems relating to anti-depressant drugs. My doctors all seem baffled by it. I haven't tried Welbutrin, but Paxil, Lexapro, and Zoloft all make me hot. Sometimes I'm afraid I'm going to burst into flames, and humidity makes it a lot worse. So if the one your on works otherwise, no reason to change. Just have to deal with the heat.

mr_subjunctive said...

Yeah, officially this is a rare (<1%) side effect, but it somehow seems less rare when it's happening to you.

Andrew said...

I find that with good soil the next most important thing is probably temperature. We'd never had much luck with streps until this year (when the temperature was much cooler than usual). This also let us put them in a south window and they've been doing great. Granted the same conditions, same soil etc but hotter weather they'll fall apart fast.

Kenneth Moore said...

Dude, I am so far behind on my blog reading. I was eagerly awaiting this, for the exact reason of "how to take care of my Streptocarpus." I've had my "Vampire's Kiss" for just over two months now. I lost one leaf that was on its way out when I got it, and some other leaves got a bit bigger, but it has been pretty slow... I need to pot it up, but I was scared of messing with it because of the cloud of doom that surrounds these plants. I figure that if I haven't killed it yet, it's slightly amenable to my care. Let's see if I can get it to survive a potting up...! (Propagation by various leaf-cutting techniques didn't work for me, either--0% success rate. Sigh.)

rusigrl said...

I have been growing streps for about a year now. I find two very important requirements: very light, porous soil (I mix perlite into African violet mix, 1/3), and fertilizer that has a ratio of low N and high K (three times or more). I get more flowers and decent growth. One thing I have recently discovered is that each leaf produces the flowers at the base, and once that base stops, you should remove the leaf. This stimulates the strep to grow new leaves, and hence, new flowers! I do not let my streps wilt, but I do let them dry out between waterings.

Utsikt mot Lurfjellet said...

Propagation from leaves or pieces of leaves is a very, very slow matter with these plants, lack of patience may cause one to toss the cuttings out before they start to produce new growth. It usually works for me, but not always. Sometimes a cutting rots, and that's goodbye.

Emmet Cat said...

Loved reading this 'only gift in order to ruin someone's self esteem' :D
I too had a try with Srep's and it has had mixed results. Sometimes one will just reach the end of it's tether and die it short order.
What I realised quite quickly is they do not like to be hot. I think this can be a bigger issue than screwing up the watering.
But overall I find them harder than African Violets, partly because their death looks so dismal.
Great site, thanks :)

cupoteacoast said...

I'm from New Zealand where Streptocarpus grow well as a pot plant. We have a temperate climate (zone 7) and nil air conditioning. Streps are lithophytes so hate soggy feet and heavy soils. I grow mine in orchid bark which they like. They are higher altitude cooler climate plants and will not thrive in heat. Give them bright light-indirect sunlight, never direct sun and damp feet but never sopping wet. The key is that they are a lithophyte, very similar conditions to an epiphyte, which means excellent drainage. Only water when dryish. They also grow well here in sphagnum moss mixed with bark and enjoy a good feed. Not so good in potting soil though.