Restoring Bottomland Prairie, April 2016, Part 2: The Vetch Stretch! (1)

Crown Vetch dominates the understory in
the buffer along McDowell Creek.

I've been spending every day since mid-March digging up Crown Vetch.  

As long as we've had a creek buffer (since 1999), we've been plagued by Crown Vetch (Coronilla varia), a horrible non-native invasive plant that was brought to this country with the best of intentions.   (What harm has been done over the centuries by well-intentioned people?)

Crown Vetch changes soil chemistry to the detriment of native plants.  It forms tangled mats that eventually become a monoculture.    

I sit under the plums on the ground and dig up the vetch
with a trowel.  Sometimes it's hard to find a place to sit!

Crown Vetch forms a
monoculture.

While restoration opens the door to biodiversity, Crown Vetch slams it shut.  

Above all, we want to keep Crown Vetch out of the prairie restoration in the Creek Field.

But every year, it comes back to the buffer that adjoins the Creek Field.  We've mowed it in the open areas and spot-sprayed it where we could.  

Reducing the size of
the "apron"

But in the plum thickets, the vetch climbs up on the plums, completely covering them.  (How diabolical is that?  --to use a shrub's own structure to rob it of its sunlight!?!) There is no way to spray it while sparing the plums.   So almost all the wild plums are surrounded by a circular apron of vetch.   That apron grows and grows and covers more and more--until vast stretches of understory are nothing but vetch.  

This spring I decided to go after that robber's den.  If the invaders stayed under the plums, it would be one thing.   But they continually venture out to steal the life from more and more land.    Three times they started small patches in the Creek Field!  

Deci is in a cleared patch., and I
am in another.  I am slowly pulling
up the last fingers of vetch that
separate the two.
That's my tool bucket in the foreground.

Two, three, four, sometimes six hours a day I've been spending at this task.  

This isn't the half of it.

I use a trowel to get under the plant,
snips to cut off rhizomes or roots that
won't come up, and a jar of biodegradable
stump killer for  the cut ends.  

Sprout with "beard" of roots

Multiple sprouts on one rhizome

I am learning why Crown Vetch is so hard to remove completely.   There may be a tiny sprout of three or four leaves but underground that sprout can be connected to multiple hairy beards of roots, as well as an entire network of pale, tan rhizomes.   And somewhere nearby is at least one caudex--a bouquet of stems, at or just beneath the soil surface, that has become woody and hardened into a bumpy knot.   

Woody caudex with spidery
rhizomes & roots.  When dug up,
the spider-legs hang down like a mop-head 

That knot appears lifeless, but it isn't.   You can see new shoots springing up out of it, as well as a mop of stringy rhizomes & roots  hanging down from it.   

Caudex with new shoots
and mop-head of rhizomes
and roots.  

Meanwhile, the leaves piled on top of each other in a mat may spring from separate rhizomes and root systems underground.  Herbicide will claim the surface layer and its underground support system for sure, but the other layers and their support systems will survive.   This is a plant with many survival strategies.   It's got a Plan A, B, C, and even D, which is the production of pods and the easy germination of its seeds.  

Last-year's tendrils (which
Crown Vetch used to clamber
over the plums) can make it
hard to reach this-year's vetch.

Absolutely thrilling, after the Crown Vetch has been dug up, is the reappearance of native plants!

More on that in the next post.