Parasite and Partner: the leafless, rootless Dodder

As we put this parasite into our seed mixes, we remember regularly getting alarmed alerts from summer visitors to Somme Prairie Grove: "There's some kind of parasite taking over! Can anything be done?!?"

Be calm, friends. We plant it. 

It's a great partner in restoration of ecosystem health and biodiversity. 

At first we see just a few pale vines, searching around:

Then they start to encircle and cling:

And soon, it's clearly having an impact:

One of the common names for this species is "love vine." But it does not just embrace. It kills, or at least severely depletes.

Those coils are not strangling. They're sucking out nutrients.

It may cover large areas of prairie or savanna:

It thrives where there's heavy domination by one or a few aggressive species - tall goldenrod, woodland sunflower, saw-tooth sunflower, or mountain mint. It seems to be able to reduce their dominance enough that diverse species can then be seeded in. 

It's an amazing plant. When a seed falls to the ground, it waits until the following spring, and at just the right moment, it germinates. But it does not put down a root, and it never makes a leaf. Instead, it uses the energy packed inside that seed to reach out for the stem of a victim. 

Is "victim" the right word here? One night on Jimmy Kimmel's late-night show, Jimmie began with the words, "Hi! I'm Jimmy Kimmel. I'm the host, and you're the parasites." Botanical humor strikes again.

But indeed, perhaps "host" is the better and more objective word.  

Though, as you see the assault continue, it can be hard to be coolly objective.

We see two species of dodder at Somme. Most of the photos here are of Cuscuta gronovii, common dodder. We also see rope dodder, Cuscuta glomerata, shown below:

Below, the main victim of common dodder is saw-tooth sunflower:

Or below: on woodland sunflower and tall goldenrod: 

If a host invited me to something and I suspected to be treated this way, I don't think I'd go. 

And this is still early on. Soon the green will bleach out of the host's leaves. The dodder will start to make buds, then flowers, and then seeds. 

When they emerge, its flowers will look like this:

Dodder often leaves other species unaffected, but the aggressive species had been so dominant, that there's now mostly bare ground. 

We broadcast the seed of diverse species into these bare spots, and our impression is that they do pretty well. The monoculture of aggression is history. We should do more careful studies. Perhaps others could do so as well.

Acknowledgements:

Thanks to GoBotany for the close-up photo of dodder flowers. 

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