The Exploding Salvia Elegans

At the beginning of the summer, I planted five of my Salvia elegans plants in the back yard, and four of them are doing very nicely. (No flowers yet, but apparently it's early for flowers. So I will be patient.)

The fifth plant, though, has had a patch of trouble lately, beginning with the husband "bumping" it with the lawnmower. I had some trouble understanding this when first told about it: we have a border around it that shouldn't be lawnmower-permeable. It was a heavily-improvised, non-professional border, granted, but it'd be enough to keep a person from going over it with a mower to bump the base of the plant. When questioned further, the husband said that it wasn't so much a bump, per se: a couple branches of the plant caught on the mower or something as he was going by, because it had grown over the border, and they got pulled hard enough to break off.


No big deal really. It's a big plant; you'd think it could lose a couple of branches here and there. It didn't look great, but at this point I could still tell myself well, it's a fast grower, though: maybe it'll fill in a little before it flowers.

But what actually happened was that: a few branches were broken, but didn't show the damage until a day or two later, so those came off. And then we had a few really windy/stormy days, which snapped away a few more, and then after that, one day playing fetch with Sheba in the back yard, an errant tennis ball landed a few inches from the poor plant, and Sheba exploded what was left of the plant while retrieving the ball.

At one time, there were two matching plants on either end of the garden shed. Now, well, see for yourself:

(That's Solenostemon scutellarioides 'Glennis' in the middle.)
Not so matchy anymore.

This was all quite the learning experience for me, since I really had no idea that pineapple sage was so brittle, or that the branches depended so much on one another to serve as windblocks. I mean, we've had bigger storms this summer; this plant had dealt with wind repeatedly before this. It's just that apparently once they reach a certain size, the stems get both really brittle and really good at catching the wind.

And, you know, catching dogs.

And lawnmowers.

It's probably good we don't have a lot of airplanes flying overhead here.

Nothing to be done about it at this point. It's basically toast. I was going to cut it down and turn it into a bunch of cuttings to overwinter for next year, but on Tuesday, I found that all the big Salvias in the yard, including the "bumped" one, also have whitefly (another kind of exploding that pineapple sage can do, it turns out, is producing a thick swarm of whiteflies when poked with a stick), so that's probably not happening. I have one tiny cutting that's rooting in water in the living room, which I took a while ago and looks like it will be the ancestor of next year's plants, because it's the only one I can be reasonably sure is clean.

Still, as long as the plants all burst into glorious bloom when they're supposed to (and they are beginning to bud, so this should happen soon), and we don't have any further "bumping" incidents, and I don't wind up bringing any whitefly inside with me, it'll all be worth it. Right?

Work-related: whitefly

I've talked previously about how we got our poinsettias in two different batches; the majority came from a company in Pella (IA) that appears to be a major greenhouse supplier in the area, and then we had a second batch, about 1/3 the size of the first, from a different grower in Centerville.

Along with the Centerville plants came whiteflies. A few of the Pella plants may also have had a whitefly or two on them, and we'd had some in the greenhouse already, that came in with some of the things that had been outside, but we'd undertaken a pretty serious effort to get rid of the stuff that came in from outside (nearly killing a few Hibiscus in the process, though they did all survive in the end), so: one, it was frustrating as hell to be bringing in new whiteflies and unable to stop them, and two, I'm pretty sure Centerville is responsible.

This is what they look like: this one is photographed on the back of a poinsettia (Euphorbia pulcherrima) leaf. The picture, if you open it in a new window, shows considerably more detail than I've ever been able to see with just my eye; normally I just see a tiny white rectangular shape and start leaping to conclusions.


Now for a confession: whiteflies scare the crap out of me, more so than any other bug, even though they're not necessarily as damaging or as difficult to get rid of as some other bugs.¹ I had a small invasion of whitefly in late winter this year, brought in on a plant that was huge, and beautiful, and (most importantly) free, which meant I didn't inspect it as closely as I might have. (UPDATE: I have since determined that the bugs in question were not whitefly, but were some other, as yet unidentified, thing that has a particularly strong affinity for Sansevierias.)

(The trojan Sansevieria.)
The infestation never got as bad as it could have, because I went into full alert mode and started hosing down all the plants with rubbing alcohol², and I hand-defoliated a few to remove pupae. Eventually the crisis passed. But whiteflies still freak me out, because unlike spider mites or mealybugs, they fly.

Happily, my observations at work have shown me that they're not that mobile. In theory, yes, they could fly around your home, laying eggs on every plant as they go, but they're not that ambitious, and flying seems to tire them out quickly: the ones at work rarely spend more than two seconds in the air at a time. In fact, if you turn a leaf upside down and find one there, it will probably be too lazy to fly away,³ which is how I managed the photo above.

They also have strong preferences for which plants they like and don't like. Hibiscus is a big favorite, as are poinsettias. We've also seen a lot of them on sweet potato vines (Ipomoea batatas), various herbs (don't recall which ones specifically) and ornamental kale (Brassica oleracea). My own infestation centered mainly on two plants: the Sansevieria they arrived on and a couple Euphorbia trigona that they enjoyed laying eggs on.

Supposedly the favorite color of the whitefly is yellow. I don't know about this personally. In my experience with the (white, yellow, green or red) poinsettias, eggs and adult flies are usually on the underside of the green leaves. If disturbed, they do often settle back down on a yellow or pale green leaf or bract, but I think that's because the points are just starting to bloom, so yellow and pale green are the colors of the topmost leaves/bracts, and the whiteflies are just trying to land as soon as they can. So I'm not convinced. They don't go out of their way to land on the yellow sticky traps we've got laying around for them.

As far as whitefly control goes, the most effective by far seems to be Marathon (imidacloprid), which the Pella group of plants had already gotten before they came to us, and which we've added to the Centerville batch but probably too late. Imidacloprid is a derivative of nicotine which can be absorbed by a plant's roots and taken into its tissues, effectively poisoning all parts of the plant (this type of insecticide is called a systemic insecticide). It comes with its own problems,⁴ but it does seem to work. The alternative, walking among the points, turning over leaves, and squishing flies with my fingers, is also effective, more entertaining, and less likely to result in pests becoming resistant, but it's also much slower and doesn't affect eggs, larvae or pupae.

Imidacloprid is approved for indoor amateur use (and it's also in a lot of treatments for fleas on cats and dogs), usually as a spray. We sell a few different formulations of it at work. Yellow sticky traps might also be helpful in small infestations, if you can place them close to the affected plants without actually touching the affected plants, though I'm skeptical, as I've indicated. Yellow sticky traps do have going for them that they're not toxic (at least, not if used as directed - I wouldn't lick one). But, as with all pests, the better approach is to not get them in the first place. Check your plants before you buy.

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Photo credit: me.

¹ (If I were more rational, I would be more alarmed by mealybugs.)
² Exaggerated for comic effect. Do not use hoses to apply rubbing alcohol to your own plants.
³ (I sort of imagine that the one in the picture is looking back at me with an annoyed expression on its face, saying something like, "Do you mind?")
⁴ It could be responsible for some or all of the recent decline in honeybee populations. Though the jury is still very much out on that, and there seem to be as many theories about the bees as there are people looking into the situation.