Sunday, August 12, 2007

Invasion Alert!

The Wanted posters above were on display at the Farmer's Market last year; I've been holding the photo (taken on one of those glaring Arizona days) 'til I had a couple of pictures of the culprits. Enemy plants listed above: Scotch thistle, hoary cress, Russian knapweed and...

...Dalmatian toadflax, aka butter-and-eggs, scientifically known as linaria vulgaris. It's a pretty thing that you see around town; little wonder it was imported as an ornamental from the Old Country back in the 1600s. Today, the dang plant is found in all the states -- from Florida to Alaska; that's real adaptability for you. I too thought this first cousin to the penstemon and snapdragon was pretty, so I uprooted one or two and planted them in my yard. Now I know why they're such a problem. They seed prolifically -- and also spread via underground runners. Almost impossible to get rid of. Flagstaff has a much worse problem than Prescott, BTW; there are roadside embankments that are totally covered by Dalmation toadflax, instead of such high country natives as red gilia or purple Rocky mountain penstemon, which is too bad!

Again, a pretty plant! Not a major problem on the local radar, but a big one along streams at lower elevations -- salt cedar or tamarisk. How come? These trees and shrubs provide shade and are excellent providers of nectar, which is very important in the production of honey . Because of their tolerance to alkaline and saline conditions, they are valuable as shade and ornamental plants. However, in many regions they have become a serious problem because they have formed extensive stands and cause great water losses. These trees take in so much more water than the native plants they displace that they have desiccated southwestern and Californian desert wetlands. So says the US Army Corps of Engineers, whose mission is to worry about waterways. Just in passing, I should mention that I took the picture above in June in a creek bed next to the road to Granite Basin Lake.

A Thousand Pardons! Speaking of invasives, I had, of course, meant to bring up the subject of kudzu, but it completely left my mind when I sat down to type. Here is an account of how the mile-a-minute plant came to the USA; here are many pictures of familiar objects (i.e., cranes, abandoned factories) that have been covered by the infernal vine. When I was in grammar school in the 30s, I heard the virtues of kudzu extolled as a new means of controlling erosion in the southern red clay country. Dotter -- you might ask your DH which government agency sponsored kudzu...

9 comments:

  1. Anonymous5:35 AM

    These I haven't heard about. Kuduz is one I have. Seems it grows and grows and is almost impossible to get rid of.

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  2. Such pretty pests! I had the impression the Forest Service was spraying Scotch Thistle by mistake. Should have known better! I do love Scotch Thistle..
    Are they still after Russian Thistle?

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  3. Steve -- I recalled some remarkable kudzu pix & consulted The Google. The URLs have been added to the post. Fortunately, the SW is not the perfect climate for the vine that ate the south.

    Brain -- Aren't they pretty, tho? I'm pretty sure that Russian thistle is also on the fecal roster...

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  4. Anonymous10:12 AM

    Thanks for the update. Interesting story and pictures. If you visit my blog and see little there, not to worry. I've reduced it to a basic one and will close it down shortly. I want to start a new one, but have to think about it. I'm not going anywhere, just don't want to feel obligated to visiting the sites of folks that stopped in. You are not included in that category. Always a pleasure visiting here.

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  5. Isn't it a shame that such pretty things, can be so bad for so much.

    -sigh- I remember Butter-and-Eggs. Never knew it was so invastive.

    Around our plot of land, it's the ding-dang Binder Vine which has us at the end of our rope. Grrrrrrrrrrr....

    Mari-Nanci

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  6. Anonymous9:38 PM

    Mamasan--Har. DH claimed, oh, no, it wasn't his agency. Har!

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  7. Steve -- I'm looking forward to your new blog. Are you continuing with your picture posts?

    SnS -- I don't recall butter and eggs being a big problem in Illinois, tho it was a common roadside plant. Is the binder vine the same as our bind weed, a sort of morning glory?

    Dotter -- I wondered what he would say. I know, his agency turned over a new leaf when it changed names.

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  8. Anonymous6:42 AM

    Interesting post.

    A major problem here in Florida (south of the "frost line") is the Meleleuca, a member of the myrtle family originally from Australia. It was imported in the early 20th Century for the explicit purpose of drying out wetlands.

    It turns out that they were not only highly effective in that role, but also extremely prolific. It is estimated that there are now at least a billion Melaleuca trees in the Everglades. It's no longer legal to plant them. However...

    Melaleuca are incredibly aggressive here, where they have no natural enemies. In Australia they grow in small clumps, and are kept in check by several natural enemies, among them a beetle that was tried here, until it was found that they enjoy other myrtle species as well. Here, they grow in dense forests with only inches between the trunks, which can reach three feet in diameter. Further, they exude a natural herbicide from their roots that keeps competition in check until they are established. Nothing can grow in the clumps -- not even baby Melaleuca. That's not a problem, though, as they propagate via tiny seeds that are easily spread.

    I've taken folks from Down Under along I-75 in Miami-Dade county and they have looked at mile after mile of densly-packed trees and wondered aloud what they were. They were astounded to learn that they were the "Punk" trees common across the Antipodes. They aren't out of control there.

    It doesn't pay to fool with Mother Nature.

    Nice blog.

    Bill Webb
    http://flwetlands.wordpress.com

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  9. Welcome, Bill. And thanks for a bit of education. I was aware of the drainage problem in the Everglades -- but not aware that Oz had taken its revenge for the prickly pear cactus! Your blog's an interesting read, esp. for a one-time Florida resident (Jax).

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