A Fabulous Cross-Generic Hybrid

Last week we had an amusing episode relating to a particularly interesting plant down the street from me. My friend/compadre/mentor Charmain Giuliani, who teaches Plant ID (among other subjects) in the Environmental Horticulture department at my Alma Mater, CCSF, wanted to get a cutting of this vine-like shrub for a discussion on unusual hybrids. On her way to school that day, she stopped by the house in question to ask if she could take a snippet, because no self-respecting gardener would take a cutting without asking (in broad daylight, ahem). Nobody was home, but a neighbor was outside and was kind enough to call them on her behalf. Basically, they told him to relay to the crazy lady to leave their damn plant alone. 🙂 But Charmain, being the persistent plant enthusiast that she is, left them a note. They were kind enough to call and she proved not to be some random crazy person, and was able to come back for the cutting she needed.

So what’s so interesting about this plant to make all that worthwhile? It’s a cross-generic hybrid, that’s what.

Huh? What’s that mean?


First, the basics of categorizing and nomenclature (naming things). The standard 7-tier scientific organizing that helps us understand how living things are related is Kingdom, Phylum, Class, Order, Family, Genus, Species. When it comes to horticulture, the greatest focus of understanding is built around the last three – Family/Genus/Species. All living things are categorized this way. People, for example, are in the primate family, and Homo sapiens is our genus and species. Right? Right.

When it comes to cross-breeding, generally it can only happen on the specific (species) level, within a genus. Meaning, you can take two different species of roses and make them bump nasties, and you’ll get baby roses. It’s “easy”, and it happens in nature all the time, as pollinators diddle one flower after another and leave pollen behind. You can cross, for example, Agave attenuata with Agave shawii. The resulting plant will have characteristics of both parents. That’s what hybridizing is all about, testing crosses to see what interesting thing results. Maybe you can create a smaller version of a huge plant so that it’s more suitable for pots, or something like that. In the case of the two agaves I mention, the A. attenuata is a large, soft, spineless agave that grows 3-4 feet across and develops a snaking “trunk”. The A. shawii is a smaller, rigid agave with dense, sawtooth-like edges. When you cross the two, you end up with progeny that are between the two in size, have very finely-toothed margins, and gorgeous blue-green leaves that undulate like graceful flames. To write the name of the new offspring scientifically, you’d write “Agave attenuata X A. shawii.” The X is pronounced “cross” and denotes that you crossed two species within one genus (Agave). In this case, the progeny is a gorgeous and desirable plant. Rather than go through that cumbersome nomenclature all the time, it has been given its own cultivar (cultivated variety) name: Agave ‘Blue Flame’.

So, that’s specific (species) hybridizing. It’s pretty much a given that you can cross just about anything within a genus. But, can you cross plants from two different genera (plural for genus)? Actually, sometimes you can!

It’s not that common that two different genera are similar enough that you can cross them, but there are common things we all know of that are cross-generic hybrids. A mule is the classic example. Horse nasty bumps donkey nasty and you get a mule. Camel + llama = cama. Lion + tiger = liger. Things like that. They don’t usually happen, but they can. More often than not, it’s because people made it happen. Socially in the wild, animals stick with their own kind and don’t go a-philanderin’ with other species. We’re usually the sicko’s behind making that happen. Not always, but often enough.

One thing that’s interesting to note, though, is that cross-generic (or intergeneric, as it’s called in the animal kingdom) creatures are sterile. They still have all the jiggly bits, but can’t reproduce. With plants, you’ll still see flowers, and the flowers will still produce nectar to attract pollinators, but the resulting fruiting bodies with produce non-functioning seeds or no seeds at all.

That’s a long buildup to this plant I’m nerding-out on, isn’t it?! Whew.

There’s a nifty shrub that grows very well around these parts, called Fatsia japonica (Japanese aralia, it’s commonly called, or just “fatsia”). It grows up to about ten or twelve feet tall, likes a bit of sun but can handle full shade, is reasonably thrifty in its water usage, and grows fine in a large pot. It’s got tall, straight trunks, and grows many of them from the base. The leaves are generally “maple-like”, soft to bright green, glossy, and huge like dinner plates. It’s a great background plant in a garden: its form and color make a nice foil for other plants and it’s a soothing presence in a garden. The shiny leaves pick up light and brighten dark corners nicely.

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Another plant that’s all-too-common around here is ivy. It’s such a pain in the ass, ivy is. It’s everywhere. It’s prolific. It seeds easily because it flowers and fruits and the birds eat it and disperse the seeds and it quickly takes over any space where you’re not diligent about it. Its roots are difficult to dig out, and any piece left behind will sprout anew. Also, any piece of stem left on the ground will root and grow. The botanical name of the basic ivy is Hedera helix. It’s a love-hate plant. Mostly just hate, actually, but it’s pretty when it’s contained and in the right spot. And, it can be useful for erosion control and that sort of thing. I love the smell of it when it’s cut, actually (and not because it’s the smell of victory).

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So, here’s the nifty part. Fatsia can be crossed with Hedera, and the resulting plant is called Fatshedera. Properly, it’s written as X Fatshedera lizei (“cross fats-header-uh lizzy-eye”). Note here that the X is before the generic epithet (the genus name), which indicates that the cross was between two genera. Ooh, how I do love nerding on this stuff. 🙂 The lizei part of the name comes from Lizé Frères, which is the nursery in Nantes, France, where said nasties were made to bump in 1912.

The reason they can be crossed is that they’re within the same family, the next tier up on the 7-layer bean dip that is scientific categorization. The family in this case is the aralia family: Araliaceae. But that doesn’t mean that all critters within a family can be made to create these sterile hybrids. Roses and apples are both in the Rosaceae family, but try as they might, no nursery breeder has ever been able to come up with a Rapple.

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The fatshedera, or aralia ivy, really is a splendid plant, showing the best qualities of both the parent plants. The leaves are the same glossy, soft green of both the ivy and the fatsia. They’re much larger than the ivy, though, and significantly smaller than the fatsia. If you look closely, you can easily see how the leaves are descended from their parents. The flowering parts of all three plants are nearly identical in appearance and form, too. The best part, though, is that it grows sorta vine-like, but without getting out of control! The stems will grow ten or twelve feet (sound familiar, like with the fatsia?) but do not grow the structures that make it cling to buildings. That means that it will only grow up whatever structure you train it onto, but it also means it’s not going to latch on and pull off your shingles or send roots under the siding and pull your house apart. It can easily be trained up a trellis or fence, and can be trimmed and shaped like a shrub. And it won’t completely smother your house like regular ivy will if you neglect to trim it before and after every meal.

The one down the street from me is truly the most spectacular specimen of this plant I’ve ever imagined. This is one of these houses where you have a gate from the street into a covered courtyard. There’s usually open ground for planting on either side of a walkway, and you have to cross to the far end of the courtyard to get to the staircase that leads up to the front door in the center of the house. If you’ve been around San Francisco, this is the standard architectural style of the Outside Lands (the Sunset and Richmond districts). This fatshedera is planted inside the gate, in their courtyard, and is trained out through the gate, where it’s cabled to suspend on the front of the house. Passing casually by, all you can see is a shrub against a house. But on closer inspection, you see that they’ve left the narrowest of openings in the front of the plant, and actually have to part their way into the plant to get to their gate. I mean, how frickin’ awesome is that?! Charmain and I have both been noted for making plants the purpose of the garden, to the detriment of people trying to make actual use of the garden (as opposed to plants being the framework around the people-spaces). This particular fatshedera really floats our collective boat.

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Thank you to the homeowners who decided to call back the crazy lady who wanted to cut their plant. 🙂 Because of you she was able to bring to her class samples of Fatsia, Hedera, and Fatshedera, and share the joy of cross-generic hybrids. Hopefully her current students will be as enthusiastic to learn about it as I obviously was!

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