If you spend much time outdoors here in Southern New England, you might know a thing or two about invasive species. Bittersweet, common buckthorn, autumn olive, multiflora rose—they grow wild at the edges of lawns, on open roadsides, along woodland trails. They are not native to this part of the world, and they can grow almost unchecked, much to the chagrin of the gardeners and landscapers and conservationists among us.
 
There is another such species you likely have encountered (and if you haven’t, I have some fine specimens growing in my backyard!). It’s a scrubby green herb, about thigh-high, with small, white, cross-shaped flowers and triangular leaves whose peculiar, pungent aroma hints at this plant’s name:  garlic mustard.
 
Garlic mustard is appreciated by herbal medicine practitioners and enjoyed by edible plant enthusiasts. But most conservationists and gardeners can’t stand it, because it is one of the most unruly, uncooperative invasive species out there.
 
It grows faster than native species. It survives disturbance better. It produces substances that inhibit the growth of other plants nearby. It tastes bad to the herbivores that might otherwise munch on its foliage. A single garlic mustard plant can produce hundreds or even thousands of seeds annually, and those seeds stay viable in the soil for up to five years, waiting for the conditions to be right to spring forth between your carefully-laid flagstones or in the middle of your award-winning pumpkin patch.
 
All of which is to say, garlic mustard takes its invasive species label seriously.  Once it takes root, you will never get rid of it.  You can try pulling it up; you can try cutting it down; you can try spraying; you can try praying; but once it takes root, it is pretty much unstoppable.
 
Jesus said, “The kin-dom of heaven is like a mustard seed that someone took and sowed in his field; it is the smallest of all the seeds, but when it has grown it is the greatest of shrubs and becomes a tree, so that the birds of the air come and make nests in its branches.”
 
As a person with a degree in environmental studies, and as a frequent hiker, and as an amateur gardener, and as a lover of creation, I have some opinions about the problem of invasive species. But despite my ecological loyalties, I think garlic mustard is a pretty good metaphor for the divinely planted, inexorably growing, unstoppably spreading realm of God.
 
Of course, we humans can help it along. We can loosen the soil to make it easier for God’s realm to take root. We can fertilize it with mercy and generosity to help it grow. We can pull out the weeds of injustice and selfishness that sap its resources. What we do matters a great deal—and if you’ve looked at the world around us recently, then you know that God’s realm can use all the green thumbs it can get.
 
But even if we do no such thing, even if we turn our backs and throw up our hands, the kin-dom of God will grow nonetheless. Once that tiny mustard seed has been planted, you will never get rid of it. Not violence or hatred, not suffering or despair, not racism or misogyny or transphobia can keep that plant from growing. There is nothing—not even death itself—that can put an end to it. Once it takes root, it is pretty much unstoppable.