Pennywort: A Plant Whose Time Has Come

It's official: my back yard looks like hell.  The trees and shrubs are bare, the berries have been eaten, the perennials have died back.  All that is left is pennywort.  Acres and acres of pennywort.

Okay, I exaggerate.  I don't have acres and acres.  But if I did, they would be covered with pennywort. 

From our elevated deck, the back yard looks like a sea of pennywort.

For those of you who haven't had the pleasure, pennywort (aka dollarweed or Hydrocotyle in Latin) is an invasive, low-growing riparian or aquatic plant that spreads by seeds and runners.  In other words, it's a weed that takes over wet areas.   

Pennywort forms a dense mat. You can rip off the top layer, but the roots will remain.

My pennywort invasion is relatively recent.  When we purchased the house in 2005, there was actual grass in the back yard. The previous owner had no garden, but he did have a lawn, and it wasn't half bad.  How he managed this feat is beyond me. The area directly behind our property is an officially designated wetland, and with the squish-squish-squish you make walking in our back yard, you would not be off base to wonder why our property escaped this designation. 

Of course, even under optimal conditions lawns require a ton of work, especially if you have no intention of hiring someone and no interest in using chemicals.  So I decided to let it go and carve out a pseudo rain garden instead.  I planted winterberry holly, clethra, hibiscus, and callicarpa; some cinnamon ferns and juncus; and loads of Louisiana iris, bee balm, and turtlehead.  The pennywort showed up on its own.

Most of the time it doesn't bother me.  After all, for nine months out of the year there are plenty of pretty things to distract the eye.  But in winter, when all that's left is that spongy sea of weeds, I loathe it.  

In the warmer months, the pennywort blends in with the rain garden theme.

The funny thing about my pennywort is that it almost looks intentional.  More than one person has asked about "that interesting groundcover," and I don't think they were being sarcastic. They may have mistaken it for dichondra, another weedy groundcover (or groundcovery weed, depending on your perspective).  The difference is that you can actually remove dichondra should you ever decide to reclaim your lawn.  In my perpetually wet back yard, the pennywort is here to stay.   

Pennywort is not without its fans.  It's native - hurray! Plant foragers and wild food aficionados tell us it's nutritious and delicious.  Louis the Plant Geek highlights a variegated version that is actually quite pretty and looks great spilling out of a container.  And the USDA, bless its heart, is worried about Hydrocotyle ranunculoides, which is endangered in Illinois, New York, and New Jersey.  Clearly this is a plant whose time has come. 

Maybe that's all I'm looking for - permission to call this invasive mess an eco-friendly groundcover.  Would I change my tune if pennywort became the new "it" plant?  Probably.  I'm as gullible as they come where plants are concerned.  Put it in a pot, give it a nice name, and stick a price tag on it.  I'm there.