Question
About two months ago members of our HOA planted an ornamental tree, several shrubs and a few perennials in two garden plots on an open lot in our neighborhood.  The lot borders open space and is not fenced.  All of the flowering bushes/shrubs (butterfly, spirea, potentilla, sun rose) and the daylily perennial in one of the plots gradually lost their flowers within a couple weeks but their leaves are still green and alive.  I figured (and is was suggested) this was just normal transplant shock.   Last week I noticed that "something" has started digging holes under the planting area in that same plot.  Both plots are covered in rock; the animals are digging in from the edge just outside the border in several different areas.   I have never seen any rodents of any kind out there, they must be nocturnal.  I'm concerned they are eating the roots of everything we planted.  I flooded the largest hole with water (it must have taken 100+ gallons before it filled up), but am wondering if there is a better way to rid the area of these pests permanently.  I remember now that when we planted the pear tree, the hole we dug 2+ feet deep collapsed into a pretty good size tunnel/cave that was obviously formed by some animal.  We tried to "plug" it but still planted the tree right on top of it.  With the new digging we see, I wouldn't be surprised if these animals are working to restore and expand their tunnel/cave network - what should we do?

The tree is wilting a bit and a small percentage of the leaves are turning brown and appear "diseased".  Is this a sign of the roots being eaten or is this also normal transplant shock?

Answer
Hi,

I've seen similar that turned out to be moles first tunneling for worms. After the tunnels are established then voles and rats use them to access and eat the roots.  It is a difficult problem to control.  Poison peanuts will get the rats and voles but not the moles usually. I'm not too excited about poison since it can end up killing pets etc. Covered snap traps baited with peanut butter is what I have used and at least gets the voles which are the most damaging.  Dig out a tunnel area, set the trap, and cover with a board.

The tree is obviously stressed. Get rid of the tunnelers and keep it well watered with some soluable fertilizer such as "Rapid Grow".  If you mix some mint in with the water it may help discourage the voles as they hate it.