Kudzu has been spreading in the southern US at the rate of 150,000 acres a year. It outpaces herbicide spraying and mowing. It is sometimes referred to as “the vine that ate the south.” I have seen entire houses, abandoned in years past, totally covered in kudzu so thick that you would have to chop your way in with a machete or a bush axe.
The second parable (v.30-32) is even more remarkable. Jesus says, "what can we compare the Kingdom of God to? It's like a mustard seed...." He goes on to describe it as "putting forth large branches, so that the birds of the air can make nests in its shade." Many, if not most, of Jesus' listeners would have heard this language before. It is from Ezekiel 17:23 when God promises to plant a "a sprig from the lofty top of a cedar" on the mountain height of Israel" "in order that it may produce boughs and bear fruit, and become a noble cedar. Under it every kind of bird will live; in the shade of its branches will nest winged creatures of every kind." But now Jesus is talking, not about a tall, stately, noble tree, but a shrub. A mustard plant.
While some varieties of mustard were used as spice and others medicinally, in general they were considered at the very least pesky and often somewhat dangerous. Because wild mustard is incredibly hard to control and once it takes root it can take over a whole planting area. which is why mustard would only occasionally be found in a garden in the ancient world. More likely you would look for it over taking the side of an open hill or abandoned field. "The greatest of all herbs" is a comment about a plant just short of a weed. Besides, who says "behold the mighty herb?"
Using this image might have felt like a slap in the face to some of Jesus' listeners. The Kingdom of God (which they'd been promised was going to come through Israel) was going to come like an invasive plant pest? They weren't going to know how it was happening? What's going on?
Jesus often told parables that appear to be the answer to the "why did you do that?" question. It may well be that these parables are an answer to "why aren't you more focused? How come you're telling everybody and their brother about the Kingdom? Don't you have some secret teaching for a select group of special people?" And Jesus says, "I'm scattering seeds of the Kingdom. You won't believe it, but they're gonna grow like wildfire. The Kingdom is going to come and you're not going to know how it got here. But trust me, it's going to happen. And when it comes, you won't be able to chop it down like a single tree; it will be impossible to stop. It will be like mustard.".....or Bittersweet; or Virginia Creeper; or Kudzu.