Who says weeding is boring? The other day while I was weeding the side garden, I lifted up the sedum ground cover to get at the root of some stray grass. But instead of dirt, there was (surprise!) the big hole pictured here.
Size is hard to tell from a photo, but a baseball could easily fit in the hole. I thought for a moment that it might be an animal den but I didn’t see any evidence of activity– the hole was completely concealed by the plants– so I stuck my hand down the hole to see how deep it was. It swallowed my arm up to the elbow and kept going beyond where my arm could reach.
This hole is right over one of the large fissures in my poured concrete retaining wall. I suspected that the hole probably continued along the fault line in the wall all the way to the ground. Using a watering can, I flooded the hole and sure enough, water came running out of the cracks in the retaining wall. (Pardon the mess on my sidewalk– I was weeding, remember?)
What the heck made the hole? Maybe it used to be an animal den, or maybe the hole was caused by erosion behind the concrete retaining wall. Solid walls like this don’t manage water well; given enough time, the water usually wins. This wall is original to the house, so I’m betting on the erosion theory. Now that I’ve found it, I wonder just how big a cave I have behind my wall.