So we (and a working party of long-suffering family and friends) got rid of them. Nine trailer loads of agapanthus, enough branches and prunings to keep an industrial-sized mulcher going for an afternoon, a broken clothesline and many hours of weeding regrowth later, it's now time to build actual, permanent garden beds for our attempt to grow our own food. I've had a couple of temporary plots with zuchini, lettuce, leeks and peas going, but this is, like, actual landscaping, yo.
The soil under this former bed of agapanthus has been dug over for weeds, gypsumed, zoo-dooed, homemade composted and cultivated to bits. And it gets great sun - now that all the foliage has gone from the north side, light can get through. A victory.
* Only the clothesline was hurt in the making of this post.