Wednesday, July 13, 2005

Invasion of the Aliens

The tsunami did more than kill people and suck up large amounts of graft and corruption. It also created an alien invasion of plant species that moved further inland:

Nearly six months after the disaster that killed more than 31,000 people in Sri Lanka, studies have found that the tsunami waves have pushed seeds of so-called alien invasive species from their coasts farther inland on the tropical island, the United Nations Environment Program said.

“In some areas, including important national parks, the wave has encouraged the spread of alien invasive species, such as prickly pears and salt-tolerant mesquite,'' the agency said in a statement.

Neither species is native to Sri Lanka, but they existed in small numbers in limited coastal areas, said Gehan de Silva Wijeyeratne, the country's best-known nature expert. He did not say how the species first arrived in Sri Lanka.
Notice they just mention in passing the fact that the plants were already on the coast, evidently put there by the Plant Fairy (i.e, somebody thought "hey, let's get something different. Everyone else has palms and fronds. Let's do mesquite." And so they did. And along comes Mr. Tsunami, who airmails this bright idea further inland).

“Now they can pose a threat to our ecosystem,'' he said. “Our local plants and animals have not co-evolved with these alien plants so when alien plants dominate in the ecosystem they will reduce the diversity of the local fauna and flora.''
I'll say. Where we live, the Japanese kudzu and honeysuckle threaten the life and limb of many a tree. But the special scourge in our yard is this:

The mimosa tree

Beautiful,no? But invasive doesn't begin to describe the torture of being owned by such a beast. Normally, mimosas live about fifteen years or so. Some plant biologists even term them a shrub rather than a tree. Well, this monster is going on thirty years old now. It's at least forty feet high and perhaps fifty feet wide. To give some perspective on its size, the small red area under the tree is the bench and begonia pictured in a previous post.

All those beautiful flowers are going to turn into seed pods. And because the mimosa is in the legume famly, all those pods will have at least six seeds. And most of those seeds will be viable. Imagine the thousands and thousands of mimosas that have been exterminated in the last thirty years on this patch of land.

"Get rid of it," you say, and we will, as soon as it dies. But its beauty, though brief, is quite enthralling, and so it lives on, spilling its wretched seed each Autumn, all the season long. And the following summer is spent eradicating its spawn.

I do wonder sometimes why kudzu, blackberry vines, black locusts, honeysuckle, and oh -- especially-- mimosas haven't taken over the world.

Such a brazen bunch. Invasive aliens, all.

Hat tip: Hyscience


At 1:22 PM, Blogger Baron Bodissey said...

I estimate 1,200,000 mimosa seedlings are in the yard each year. That's based on a guesstimate average of 3 per square foot, which, as you know, is a gross underestimate for some parts of the yard.

At 3:39 PM, Blogger Dymphna said...

Hmmm... the thing is, some of them get raked up and are put in large leaf piles which gradually over the years becomes quite wonderful looking leaf mold. So if you unwittingly take that nice leaf mold for flower beds, some of those ten year old seeds sprout. In fact, most of them will!

I wonder how long they remain viable. Longer than anything radioactive, I'll bet.

At 4:18 PM, Blogger Headmistress, zookeeper said...


I've heard, btw, that Kudzu (or whatever it is) is edible. I read that in some article about natural ways to get rid of invasive plants. Just eat it up.

I've also been told that about our own invasive plant problem, one not nearly so attractive as yours. Garlic mustard. And it does have a pleasantish garlic flavor, but I can only eat so much garlic mustard in sandwhiches and lasagna.

At 4:26 PM, Blogger Baron Bodissey said...

You might want to cite this poem...

At 8:41 AM, Blogger Always On Watch said...

A native Virginian, I grew up with a stand of mimosa trees on the west side of our yard. The pods were a pain, but the trees themselves were lovely. On the really negative side, when the trees got older, the trunks tended to split. My father tried to save the mimosa trees by using bracing rods. Over time, however, those wayward trunks continued to lean and posed a danger to the house, so my father had to cut them down.

As to honeysuckle, it has taken over portions of my yard. I had knee surgery in 2000 and, for two years, was unable to tend to the annual trimming. Once honeysuckle takes over, it's nearly impossible to tame it. Right now, the heavy vines are pulling over my chainlink fence!

But here's a funny story about honeysuckle....One of my neighbors, city bred, fell in love with the scent of the honeysuckle blossoms and actually came over to dig up a starter vine. Each to her own, I guess.

I will admit that there's nothing like the smell of night air scented by honeysuckle, wisteria, and black-locust blossoms.

At 12:44 PM, Blogger Dymphna said...

Yes, those are lovely smells. We have honeysuckle and black locust, too...
Black locusts are containable since they only send out runners and it's easy to clip or pull them.
Next to all of that, honeysuckle is easy. Easier than greenbrier, I think.

The fragrance of pawlonia trees is beautiful, too. The Baron has shaped one over the last twenty years that is something to see. I will try to get a scan of his painting of it up on the blog. It has pods also, but he's able to clip those in early summer so we don't have any infestations. I hear some people grow them for's what traditional Japaanese shoes are made of.

For the last two years I've not been able to park under it as some caterpillar is eating it and leaves droppings all over my car.

I can see what you mean about mimosa trunks splitting. There are splits in the big one but I thought they were old scars from having those spinning wheel fireworks affixed to them...maybe not.

Sometimes I get on garden web sites and read of others pulling their hair out over the mimosa plague in their yard. I've learned a few mimosas are pullable by hand if they're under a foot tall. There is a grim humor in that thought.

I do wish deciduous magnolia was a weed tree.

At 6:04 PM, Blogger Unknown said...

Don't get Empress Pawlownia...get this one instead; as it is non-invasive and sterile...and produces better wood. Same thing otherwise without the invasiveness.

At 5:55 PM, Blogger Doc Conjure said...

I adore Mimosa. The first tree I ever climbed as a kid was one.

But I can assure you they can grow to have tree-trunks so big you can't hug and touch your hands around.

The only bad things about them is the seedlings and the leaves and twigs they constantly shed.


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