Wednesday, April 6, 2011

Incredible Hulk (Schefflera actinophylla)

First off, there are three commonly-grown Schefflera species, and this profile is only about one of them. I've profiled Schefflera elegantissima already, and it's hard to confuse for the other two, but the other two are mistaken for one another on-line a lot.

This makes no sense to me, because they're just as easy to tell apart: if the leaflets are longer than 4 or 5 inches (10-13 cm), it's a S. actinophylla, the subject of this profile. If the leaflets are shorter than 4 or 5 inches, it's S. arboricola, which is not. I mean, there are other differences, and there is some overlap when talking about very large arboricolas or very young actinophyllas, but that's generally enough to make the determination.1

Like, this one is pretty obviously an actinophylla. Photo credit: anonymous PATSP photo donor.

S. arboricola is not a dwarf variety of S. actinophylla, though a surprisingly large number of people seem to think it is.

Care for arboricola resembles that of actinophylla, but there are enough differences that I will profile them separately. I thought it was important to get this out of the way first, lest someone read through the whole profile thinking I'm talking about their plant, only to realize that they have an arboricola.

So.

I only remember watching "The Incredible Hulk" on TV once, at someone else's house, and I don't think I was paying very close attention at the time, because being at someone else's house was more interesting than watching TV. I know the basic story anyway, though: unassuming physicist Bruce Banner is exposed to a huge dose of gamma radiation, and shortly thereafter, when in the throes of strong emotions like rage, finds himself transforming into a large, muscular, inarticulate monster with terrible hair. (Sort of like a green Steven Seagal, but more handsome.)

Photo via Starts With a Bang; original source not identified.

In the TV show's credits, says Wikipedia, Bruce Banner is quoted as saying, "Don't make me angry. You wouldn't like me when I'm angry," which is a widespread enough quote that I knew of it for a long time before I had any idea where it came from.2 Schefflera actinophylla hasn't been irradiated, but it is huge and green, and you wouldn't like it when it's angry, either.

The common names for Schefflera actinophylla3 follow the plan [octopus or umbrella] + [tree or plant], with "umbrella plant" being the one most familiar to me personally. A lot of people apparently call them "Australian ivy-palm," of all things: I'd never heard that name before I started researching.

"Australian ivy-palm" is also only 33% correct. Schefflera actinophylla is from Australia and New Guinea, specifically the northern part of Queensland, Australia, north of the Tropic of Capricorn. This isn't an official, documented, scientific map, but it's the general neighborhood we're talking about, based on the descriptions I found of the range:

Image from the CIA Factbook (.pdf file), with modifications.

So it is Australian. It's not an ivy or a palm, though.4

Schefflera actinophylla was introduced to Hawaii in 1900 and Florida in 1927 as an ornamental. Its relative hardiness (in zone 10 and 11), quick growth, shiny foliage, and attractiveness to birds led to its being widely planted. The plants produce small red flowers, mostly in summer to early fall, in clusters shaped like the arms of an octopus or the ribs of an umbrella. Birds like to drink the nectar from the flowers.5 The fruit is inedible to humans but spread by birds.

Image credit: mauroguanandi, via Wikimedia Commons.

So we've got a fast-growing tree that produces large amounts of fruits that birds like eating. You maybe see where this is going.

Yup, it's another invasive species. It shades out native species by growing extremely fast; it can also begin life as an epiphyte and overgrow its host tree quickly enough to kill it.6 The bigger problem for people who plant them, though, is that the plants are extremely destructive on small scales too, and people who have umbrella trees planted in their yards often find themselves wishing they didn't. Not only do they (the trees) drop leaves more or less constantly, but they'll also shade out and kill anything planted near them, the roots tear up driveways, raise and break plumbing and gas lines, push over walls, smash tiled courtyards, crush foundations, ruin sprinkler systems, and just generally cause mayhem. ("HULK SMASH!") According to the commenters at davesgarden.com, this doesn't seem to be as big of a problem in California as it is in Hawaii or Florida. It could be that the Californian commenters at davesgarden.com are unobservant, but it could also be the case that humidity is an important factor in how quickly the roots grow. I don't have enough information to make that call; I just know that California doesn't appear to have a problem with invasive, rampaging Scheffleras.

The plants can also, of course, regenerate from roots. This doesn't have much application to indoor growing, or even large-scale production, but it very much applies if you have a 40-foot Schefflera7 trying to crack open your home's foundation and pump gas in. You do have to get all the roots.

Florida has, of course, put umbrella tree on its do-not-plant list, but nurseries in Florida were still selling it as of 2002, and when I worked at the garden center in 2007-09, we were getting our Scheffleras from suppliers in Florida. So one senses, perhaps, a less-than-sweeping commitment to evict scheffs from the state. One official, Dan Thayer (Director of the Vegetation Management Division of South Florida), made a tongue-in-cheek suggestion that perhaps the way to turn things around would be to spread rumors about the plant, specifically that it attracts encephalitis-carrying mosquitoes, and hope that public panic would do the rest. (Which is when I decided that I liked Dan Thayer, the Director of the Vegetation Management Division of South Florida.) Scheffleras in fact don't attract encephalitis-carrying mosquitoes, or any other kind of mosquitoes, but hey: if it'll help Florida ecosystems and homeowners, I'm willing to reinforce the association in people's minds.

Image: Tropical Plant Pictures.

Mother Nature is certainly not going to do anything about the situation. Fire will kill scheffs sometimes, but it's not a guaranteed fix. Hurricane Andrew produced wind speeds of 165 mph (265 kph) when it hit Florida in 1992, and about 85% of the Scheffleras survived just fine. Scheffs tolerate herbicides pretty well, and even when herbicides work, they generally have to be applied more than once. This is a strong plant.

Which is part of why they're so good indoors. Even with reduced light, low humidity, and confinement to a container, S. actinophylla is still vigorous, and generally pretty easy to care for, with just one major flaw.

My personal plant, October 2007. I think it's a 6-inch (15 cm) pot.

LIGHT: As a rule, more light is better, though I wouldn't put a scheff in a south or west window unless the window was partly obstructed or the placement absolutely necessary. (The reason will be explained in a few paragraphs.) My personal plant has been on shelves under fluorescent light for most of the time I've had it, which has been fine.

WATER: My experience has been that umbrella plants are very flexible about watering. Too much and the lowest leaves will yellow and drop; too little and the leaves wilt slightly,8 but they're less fussy about it than most other plants. I try to err on the side of dryness with mine, and water only when it's almost completely dry. I haven't seen it wilt, but I haven't been watching for that, either. Maybe it's subtle.

TEMPERATURE: The best situation indoors is to stay within 55-90F (13-32C), but S. actinophylla can manage temperatures outside that range under certain conditions. Established, large outdoor plants will lose their most exposed leaves at temperatures slightly above freezing (say around 37F/3C; different sources have different ideas about this), but the plant will still survive a light, brief freeze, regrowing what it's lost in short order. Whether a container-grown indoor plant could do the same, I couldn't say. I don't recommend trying to find out.

Hot temperatures may cause some temporary wilting, but scheffs can cope fine if they have enough water, and will pop back up once it cools off again.

My personal plant, July 2010. I think the pot here was 8 inches (20 cm) in diameter.

HUMIDITY: Not ordinarily a huge issue, though more moisture in the air is better.

PESTS: The main reason more moisture in the air is preferred is that spider mites loooooooove Scheffleras. Scheffs don't seem especially prone to other pests, but mites and scheffs go together like Ke$ha and autotune. This is the single biggest drawback to what would otherwise be a nearly-ideal indoor plant. Some varieties are supposed to be more mite-impervious than the species, which I'll talk about in a few paragraphs.

The best way to deal with spider mites on a Schefflera is to not buy plants that have them, and then keep the plant in a moist environment with good air circulation. I've had mites on my plant once in the three years I've had it, but it was one of those long, drawn-out infestations that never really got out of control or went away. (It might not have gone away still; I sprayed it with neem oil last summer, and didn't have problems with mites during the winter, but I don't expect to be completely mite-free, ever, because if there are mites in the house, they'll find it eventually.)

It was worse at work, because at work the heat was provided by gas heaters under the tables, so the plants were getting this constant flow of hot, dry air from underneath. Also it was a greenhouse, so there was hot sun at least some of the time as well, and if there's anything spider mites like more than Scheffleras, it's hot sun. (Which is why I wouldn't put one in a west or south window if there are other options.)

PROPAGATION: Commercial production is mostly by seed, which will germinate with about 80% success after three weeks barely covered in a moist, peaty medium. Several places on-line sell the seeds, if you want to go that route. Tissue culture is used for some cultivars.

Home propagation is generally by cuttings or air-layering. I haven't done either one for this plant, so I can't describe how to do it.

GROOMING: Actual grooming is mostly limited to removing the occasional dead leaf and dusting. They may eventually get too tall for the house, which is a problem you don't have with some plants, but I'm not actually sure what you're supposed to do about that.9 They do tend to get rootbound faster than you think they will, so it's important to keep up with repotting and check the roots at least once a year. The roots also have a tendency to shape themselves tightly to any irregularities in the pot surface, so if you plant yours in a fancy-shaped container, that curves in at the top or has lots of embossed designs, you may have to cut it apart or break it in order to repot, if you wait too long. (If you wait even longer than that, the plant may decide HULK SMASH and break the pot on its own.)

My personal plant, March 2011. 10-inch (25 cm) pot.

FEEDING: My plant grew okay when I wasn't feeding it at all, suddenly grew much larger and darker-green leaves when I started using the Osmocote (14-14-14 without trace elements), and didn't appear to change any when I switched to the Miracle Gro (which I think was 15-30-15 with trace elements). This more or less matches up with what Griffith says in Tropical Foliage Plants: A Grower's Guide.10

There are a few cultivars.

'Nova' is distinguished by the shape of the leaflets: instead of being rounded ovals, they're jagged and pointy. To my eye they look more like oak leaves, or like Schefflera elegantissima. (There's some question about whether 'Nova' is even S. actinophylla. From what I've seen, it's generally sold as such, though.) I couldn't find a free photo to use, but you can see a picture from Caldwell Nursery in Houston,11 or check the page at davesgarden.com. I'm pretty sure someone commented about 'Nova' on PATSP at some point, but I couldn't locate the comment: I think they said something about 'Nova' being more cold-sensitive than other varieties of umbrella tree. And I assume there must be other problems with them as well, because I have yet to see one for sale around here, nor were they ever offered from our supplier when I worked at the garden center.

Variegated S. actinophyllas are rare, but they do exist. They have cream and green leaves, with reddish petioles. (Davesgarden.com has pictures.) One rarely sees them for sale because, according to Griffith, they're very prone to revert to green.

'Soleil' has chartreuse foliage and is said to prefer lower light than the other cultivars; I didn't find much information about it, though.

'Renegade,' 'Alpine' and 'Amate' are similar -- all have large, dark green, glossy leaves. However, 'Amate' has a wider habit; 'Renegade' is more columnar. I couldn't figure out what the big deal was about 'Alpine.' I've never seen a plant identified as 'Renegade,' but I have seen 'Amate;' this is probably because 'Amate' is supposed to be more resistant to fungal and bacterial leaf-spot diseases. (Plants with spotless leaves are obviously more sellable, and therefore more appealing to growers.) 'Amate' is also supposed to be more resistant to spider mites; the experience I had with it at work suggests that this claim may be overstated a bit, but maybe the plant just caught us at a bad moment.

Larger plant from the ex-job; this is probably a healthy 'Amate.'

Whatever variety you have, Schefflera actinophylla is easy to please under most indoor circumstances. They're long-lived indoors (30 years is not unheard of), and they're one of those plants that provides clear feedback about how it's doing: either it's getting huge, or it isn't. Just don't get it angry: watch for spider mites, and check it regularly to see if it needs to be repotted.

-

Photo credits: Mine, except as otherwise noted in main text. You can tell the ones that aren't mine by the way they're not crappy. (Tough plant to photograph.)

REFERENCES:

General, outdoor, ecological:
USDA Forest Service
Plant of the Week
Missouri Botanical Garden
Center for Aquatic and Invasive Plants
Miami-Dade County, Florida
The Lazy Gardener (Houston Chronicle)
Hawaiian Plants and Tropical Flowers
Master Gardener
Davesgarden.com
Wikipedia
Floridata.com
University of Florida Extension
Exploring the World of Trees
.Pdf about Schefflera in South Florida, written by Dan Thayer

Care:
Plant Care Guru (warning: bad spelling)
Denver Plants ('Amate' specifically)

Cultivars:
Tropical Gardens ('Renegade,' 'Alpine,' and 'Amate' photos)
Oglesby Plants International (description of 'Soleil,' 'Alpine')
Davesgarden.com ('Nova')
Davesgarden.com (variegated)

Propagation:
Success With Seed (Park Seed Co.)

1 If it was sold as a bonsai, or variegated, it's most likely an arboricola. Actinophylla are virtually always solid green, and although it's theoretically possible for any tree to be grown as a bonsai, actinophylla's not grown that way often enough to show up in a google search. (I did find one person claiming that they grew actinophylla as a bonsai, but I'm inclined to think that they were mistaken about the species name.) When I decided that I wanted to get a S. actinophylla, it took me a long time to locate one that wasn't already a six-foot tall floor specimen, but we sold arboricolas in four-inch pots pretty much year-round.
Other differences: arboricola has thicker, more substantial leaflets, and the veins show up poorly or not at all when leaflets are held up to a strong light. Usually arboricola has more leaflets at a small size than actinophylla does, too: actinophylla tends not to have more than 5-6 leaflets per leaf until it gets really big, while arboricola can have 7-8 easy when it's still small enough to fit in a 4-inch (10 cm) pot. Actinophylla leaflets are also larger but thinner, more like a Dieffenbachia leaf in weight, and veins show up very clearly against a bright light.
Schefflera actinophylla venation.

2 For some reason, I was thinking Dirty Harry.
3 There's another botanical name I should probably mention, too: one still sees the botanical name Brassaia actinophylla. Brassaia has sometimes even been the correct name, but it is presently obsolete, and doesn't look likely to come back. As "schefflera" is gaining ground as a common name, you'll probably never need to know Brassaia, but I include it for the sake of completeness.
4 It's closer (barely) to being an ivy: it's in the Araliaceae, the family that includes English ivy (Hedera helix) and Algerian ivy (Hedera canariensis). Anybody who could look at a Schefflera and think Oh! Ivy! is pretty messed up, though.
5 I even found interesting pictures of this, and sent a message asking to reuse them for PATSP, and the next time I tried to view the page, I either got error messages telling me I didn't have permission to look at the page, or the page loaded, but without any pictures. Could have just said no, we'd prefer that you didn't. Fucking bird ecology people. So the page is here. Perhaps you'll be able to see the images.
6 This is something we see with some other houseplant species: both Ficus benjamina and Philodendron bipinnatifidum can start out epiphytically and become terrestrial once they manage to drop roots to the soil. Schefflera has more in common with Ficus, in that it can grow fast enough to overrun the host. Philodendron climbs the host until it pulls it over sideways, but doesn't smother the host, at least not as I understand it. Staghorn ferns (Platycerium spp.) don't drop roots to the soil to become terrestrial, but they're also epiphytes, and will sometimes grow large enough to pull their host tree over sideways. Epiphytes are rude.
7 The height varies a lot depending on which source you're reading: I found sources saying everything from 20 feet (6 m) to 100 feet (30 m). I went with 40 feet (12 m) here because it was the median value, but be aware that the plant may be capable of getting taller than that.
Though probably not in your home.
Unless you have 40-foot ceilings.
8 Slight wilting during the hottest part of the day is pretty common on outdoor plants, whether they have adequate water or not, because transpiration increases dramatically when it's hot. Indoors, it's less common, because the plant is much less likely to need that much water to transpire. In some growing conditions (not sure which ones those would be), plants look somewhat wilted all the time, so check the soil too, before you water, to make sure the plant actually needs it: don't go only by how it looks.
9 S. arboricola can be cut back pretty much where- and whenever, and resprouts easily; I've done that myself. I've never cut back an actinophylla, though, and couldn't actually locate anybody on-line saying they'd done it for one grown indoors. Since outdoor plants are supposed to resprout okay when cut back, I assume it's fine inside too, but I make no promises. As a result, I recommend air-layering for too-tall S. actinophyllas, because I know that way you at least get one acceptable plant when it's over. If anybody has experience with cutting one back indoors, I'd appreciate hearing about it in the comments.
10 He says they do best with lots of N-P-K fertilizer, heavy on the N, but that he "generally [does] not recommend incorporating minor [trace] elements into the potting medium for scheffleras." I don't get the impression that he thinks it'll hurt the plant, just that it's sort of a waste to give the plant nutrients it doesn't have any use for. He does say, though, that magnesium deficiency happens occasionally, and that it manifests as yellowing along the margins of the oldest leaves. So if you see that, you might try watering with a bit of Epsom salts dissolved in the water for a while, gradually increasing the amount if nothing seems to happen after a few waterings.
11 Who make a nice first impression: not only did they have the plant photo I was looking for, but their availability page has plants listed in alphabetical order by botanical name. (♥ ♥ ♥!) Sadly, they don't sell plants by mail-order, but they still have lots of cool pictures. (Check out Drimiopsis saundersiae 'Sunny-Smile'.)


18 comments:

Liza said...

Well, I guess it's a Schefflera kind of day. What's that they say about great minds?

I've pruned back Amates, and they resprout really easily.

Sentient Meat said...

I enjoyed this profile...

Four years ago I nearly lost a lush, beautiful Schefflera actinophylla to spider mites. Back then I didn't realize how susceptible and delicious this plant is to mites. Three out of 5 canes died.

But I relocated the plant from indoors to outdoors in a bright, shady spot, and it has grown vigorous and happy outdoors ever since -- albeit a bit lopsided with just 2 trunks instead of the 5 it started with at Home Depot.

It grows okay without much feeding but responds quickly and favorably to well balanced fertilizer.

Anonymous said...

Not sure if my Scheffs count as indoors (indoor tropical rainforest at our local zoo) but I cut em back fairly regularly, no prob.

Liza said...

I meant to also comment on what a thoughtful, informative post this was. So much great information. I can't even imagine the amount of time and effort that goes into one of your profiles, but I sure do appreciate it.

Also, it made me laugh how old fashioned the Hulk looks in those high-waisted jeans.

bjfrancis said...

Excellent info. I am in process of deciding what to do with my 7', Y trunk S. actinophylla. It is at least 35 years old and I quit repotting it about 12 years ago. It is intent on gowing taller than I can provide for it. But we are very old friends. The bonsai guy suggests just hacking it back and it will sprout new leaves. I am doubtful. The trunks are quite woody and why would they not have sprouted leaves when I cut off the tops? I have tried starting new plants from cuttings and was unsuccessful with first try - cut off too many of the very large leaves and potted it up too soon. Up side is it (so far) sprouts beautiful tender new leaders. I am now brave enough to cut these off and try rooting them in water (for a very long time). Your post is wonderful, gives me hope.

Bruce Haizlett said...

Schefflera actinophylla is a plant that I would not have in my yard in South Florida. It's fast growing. gets very large and extremely messy, dropping lots of big waxy leaves year round. The roots are near the surface and can push up sidewalks building foundations and get into sewer lines. It is considered an invasive species in the State of Florida. It can spread in no time. They should be outlawed in Florida.

mr_subjunctive said...

Bruce Haizlett:

Well, and then there are the encephalitis-bearing mosquitoes.

Gra said...

Hi there, great post. I have an Arboricola I keep outdoors in a shady bright spot in my yard. I got it last year and was dormant for most of the winter so I didn't really bother with it but by the end of Summer it doubled it's size. I never used fertilizer and water it only when it's dry.

I would like to prune it and bring it indoors but it's such a shame to cut off those stems. I think if you want to keep it indoors regular pruning is a must in spring and summer to keep it in check.

You can see some before and afters here:
http://green-patches.blogspot.com

Sarah SSM said...

Aha! Thank you for doing an article on this. I'm living in Haiti, and we have one in our front yard that's over two stories tall. I've been wondering what it was. Might link to this on my blog when I get around to writing my own blog post on it.

Anonymous said...

Re footnote #5. Yep, the photos are still visible for me - 5 years later. Still not positive about which schefflera I'm growing. I think probably S arboricola 'Gold Capella', but on Google pictures there was S. brassaia actinophylla that looked indistinguishable. I have a smaller green schefflera, but both were funeral plants without identification. The variegated job has been repotted into a container as large as I can handle and I think it's going to have to be cut back just to fit inside this winter. Hate to chop on it, but at the rate it's growing there won't be any choice.

Texas Anon

Anonymous said...

The schef is has buds. If they make to bloom, will it help id the plant with a Google search?

Texas Anon

mr_subjunctive said...

Texas Anon:

?

Anonymous said...

Yeah. And I wasn't even drinking or anything interesting like that. In short, the schef is growing buds and I'm hoping that if they make it to the bloom stage, a Google search will help id the plant.

Texas Anon

mr_subjunctive said...

Texas Anon:

Well, it's possible, but I'd be surprised, frankly. Google is already not wholly reliable for species searches, cultivar searches are even less reliable, and I don't know that the flowers are even different from variety to variety. More information never hurts, when it comes to IDing things, but in this particular case I don't know that I'd be counting on it to help much.

Ahmed Yousif said...

I bought mine 5 months ago and since then nothing changed, still the same height! anything to do to make it grow a bit longer?

mr_subjunctive said...

Ahmed Yousif:

That would be an easier question to ask if I knew what conditions your plant has been in, and what kind of care it's been receiving, since you've had it.

Jean said...

I have had an Umbrella Tree in a pot for 30 yrs, I have re-potted it several times, but have now given up, of course its roots are growing out like a bonsai, there are plenty of leaves and quite suddenly after all these years green buds have appeared on one of the branches, what a suprise. Can I prune this tree or will it die. I am in a moderate climate (Australia) and it has always been outdoors. regards Jean

mr_subjunctive said...

Jean:

You can prune.