Yes, this year I feel like Bill Murray battling the groundhog at the country club in Caddyshack, minus the great Kenny Loggins soundtrack! With the increasing urbanization of our area, open spaces where groundhogs routinely reside are diminishing, driving them in mass to many private and public gardens. Their paths of destruction include: creating “condo-like” tunnels in garden beds, chewing newly planted tree trunks/irrigation drip lines, snacking on both annuals and perennials, and digging up new plants.
There appears no one solution to deterring this destructive garden creature. So let me share with you some of the approaches I have used over the past 3 years. Different methods have yielded varying levels of success. I suggest applying a combination of strategies at various times throughout the garden season.
If you discover tunnels indicating the groundhog has taken up residence in your beds, I have found the combination of soiled cat litter, Critter Fence TM. and stone as a way to drive them out of your garden and off to another condo construction site. When I find the tunnel, I drop a quantity of my cat’s soiled litter into the hole, wait a week, then return with a piece of critter fencing (or chicken wire alternative), add a layer of #1/2 stone and cover with the soil turned up from the tunneling. This worked for 2 years in the gardens at the Dance Museum. It drove the party creatures elsewhere. However this year I found them back to their old tricks in one garden, so I am repeating the process to eliminate the new hole.
If you have opted for professionally installed drip irrigation in your gardens, beware. When we get these incredibly hot and dry weeks, groundhogs will chew through the piping to access water. Over the years in certain environments, I have suggested avoidance of this style irrigation and installed smaller garden specific spray heads. The water drains better in this style system and the connecting pipes installed lower into the ground.
Selecting annuals and perennials that the groundhog will not disturb is another challenge. Early in the season after annual display planting I encountered weekly digging up of the new plants. I have always incorporated adding marigolds to the displays. My father and grandfather used this in their veggie gardens to deter wildlife, so I took up the practice. Apparently the scent is unpleasant to many so they avoid the area. But this year’s groundhog entourage did not appear bothered by my old practice. I use the perennial salvia in the same way. The salvia scent often deters wildlife. But not the groundhog. It feasted on my early blooms of this plant.
Using a scented material is a common approach to deterring wildlife in the garden. One of my customers swears by the use of dryer sheets. When groundhogs took up residence under his shed….he shoved lots of dryer sheets under the foundation. The critters migrated elsewhere!
This week in an open courtyard, I discovered chew marks on a newly planted blood good maple. 
This was a first for me. I am trying an environmentally friendly Deer Away product sprayed in the mulched area around the tree to deter further damage. If that does not work, I may be doing a trunk wrap for the remainder of the season. Will let you know. Have you had success with groundhog deterring strategies? Would love to hear from you!
If you are looking to try the Critter Fence material, I have found it useful for a number of wildlife problem garden applications. Here is their website for more information:http://www.critterfence.com
As always, applying common sense and sustainability to all my garden practices.
