invasive – Towards the Moon or To the Sun

Flying Dragon, Bitter Orange

It’s a common refrain: some horticulturist or botanist sees a wonderful potential in some plant and brings it across the ocean. An effort is made to establish said plant, so that their descendants could carry out a far greater effort to de-establish it.

I can begin so many essays this way. The subject today is trifoliate orange (Citrus trifoliata or Poncirus trifoliata), also known as bitter orange, hardy orange, or (in one cultivar) Flying Dragon.

The bitter orange is a shrub which can grow to nearly 30 feet tall. What gets your attention at first sight are the long (1-2”) rigid thorns arming the twisting green stems.

While the thorns are the main feature to my eyes, it gets its name from the fruit. It is flowering now (May), and in a couple of months small (around 2 ½ inches) green fruits will appear. These ripen to orange and are both very acidic and bitter (the latter from a chemical called poncirin). I’ve read that, with proper preparation, they can be turned into a marmalade or a bittersweet condiment. To me, that’s trying to make lemonade when given lemons.

It was brought over in the mid-nineteenth century to make livestock hedges. And they certainly work for that purpose, with their 2-inch thorns! The problem, as usual, is that the possible ramifications were not thought through – namely that this hardy plant will find its way to unwelcome places. Trifoliate orange has established itself in at least 17 states.

I’ve encountered it on several properties in Georgia Piedmont, but nowhere as extensively as a tract in Jackson County which, prior to mulching, was a solid thicket of bitter orange.

Why is this pest top of mind today? I was visiting my neighbor across the creek and came across several scattered hardy oranges. I already have callery pears, another noxious plant I have special antipathy towards, advancing on me. But then, our landscape has an overabundance of foreign species that have made themselves at home here. The more one learns, the more one finds.

Curse of the Starling

If I became governor of Hell I would reserve a special room for Eugene Schieffelin and his minions in the North American Acclimatization Society, the idiots who thought it would be nice for all the birds mentioned in Shakespeare’s works to be represented in America. In the 1890’s he released around 60 starlings into Central Park. Because of one single line in Henry IV, an estimated 200 million of the aggressive little bastards currently occupy North America, wreaking havoc on native bird populations.

Why such antipathy for these morons? Why not put in Etienne Trouvelot (who introduced Gypsy Moths) or whoever shipped the wood that contained the fungus that annihilated the American Chestnut? Because Schiefflin and his cronies went out of their way to perpetrate their crime, and for a silly reason.

Humans have been bringing pests from one land to another since they first commenced to roam, and many native species and a few ecosystems have paid the price. Many are completely unintentional, from fire ants to zebra mussels. Some seemed like a good idea at the time, like kudzu or cogon grass. But Schieffelin’s crowd were whimsically Anglophilic.

Dreamers are fine. But sometimes their dreams can become nightmares.

Rogue Pears

As I write this, white blossoms are popping out behind my house — an old nemesis sneers at me. The Rogue Pear.

The callery pear (Pyrus calleryana) is an Asian native brought to the US in the 1960s. Why? The pears are small, round, and inedible. The flowers fill the air with a sickly-sweet odor. The trees are densely limby and prone to splitting in bad weather. Like many fast-growing trees, the callery pear is short-lived, lasting only a couple of decades or so. So why has it turned up in every doctor’s office park and subdivision? Three things: beautiful foliage– deep green in summer, leaves turning blood-red or wine-dark in the autumn; an explosion of flowers late in winter; quick growth to a bushy, symmetrical silhouette.

Horticulturalists created a number of cultivars, the best-known being the ‘Bradford’. We removed the thorns, we straightened the forms. As a useful biproduct, these cultivars couldn’t reproduce. You plant Bradfords, and they stay where you put them.

But, in our great and unmatched wisdom, we kept tinkering. Each cultivar had slightly different properties. Different colors, stronger limbs. And then it happens. One cultivar is used to landscape a new strip mall, and a different one dresses up an office park down the street. Some local bees visit one and then the other. It turns out that different cultivars can fertilize each other. And these new seedlings exhibit the attributes of the original, wild pear: able to grow on a wild range of soils, able to seed prolifically, and armed with thorns that can punch through a truck tire. I call them rogue pears, when I don’t use stronger adjectives for them.

It’s a contagion the scope of which you aren’t likely to notice until late winter. Come February until April, these innocuous green trees suddenly blaze white in floral profusion. My corner of the county is pretty well infested; a mere 10 years after being fallow, the neighbor’s field is a young forest, with 8 out of 10 trees being pears. But I didn’t have any inking of realize how widespread the problem was until I was a couple of hours away, driving on a highway skirting the Fall Line. In the pine plantations on either side, the midstory was packed with pears bedecked with their white blossoms. Some quick research showed the rogue pear has popped up in most states east of the Mississippi, and it has a foothold in several western states as well.

Everyone knows about kudzu. You may have heard of Chinaberry or privet or tree-of-heaven. Now that pear is on your radar, maybe you’ll start seeing it come the end of winter.

Maybe, hopefully, you’ll choose native trees for your next landscaping project.