Rodent problems can force harsh measures in a garden

Photo: Sigrie Kendrick

While leaving ornamental grasses and perennials in blossom and seed overwinter provides excellent habitat for wild creatures, sometimes that includes creatures such as voles, which are not as welcome in the garden as birds and bees. In this case, OXA volunteers have had to cut back plants in the demonstration garden to eliminate habitat for the destructive rodents.

What’s that old saying: Do as I say, not as I do?

If anyone has been by the Okanagan Xeriscape Association’s Xeriscape Demonstration Garden recently, they are probably thinking something along those lines about me.

“What is she going on about advising us to leave the garden clean-up until the spring to provide food and habitat for wild creatures, and yet the perennials and ornamental grasses in the garden have been cut back and there’s not a fallen leaf left?”

The garden does look pathetic and boring, bereft of any winter interest. It saddened me to instruct the volunteers to essentially raze the garden to the ground last Friday at our weekly Dig with Sig, but this was only done in desperation. It was an all-out effort to help get rid of four-legged pests in the garden.

We have a huge vole problem, which I became aware of this past spring when I started cleaning up after winter. I began by cutting back one of the Autumn Joy Sedums and the whole plant came away in my hands. The roots had been annihilated.

By morning’s end, I came to the heart-breaking realization we had lost a good portion of the plant material in our ornamental grass-themed garden. Nothing was left on the animals’ buffet table. Perennials, ornamental grasses, ground covers were all gone.

We are a not-for-profit organization and are constantly watching our finances, so I was trying to add up the cost of replacement as I worked. As I continued to clean away more plant debris, the little tunnels of destruction became obvious. What exactly were we dealing with and how should we approach the problem?

Even though I learned about rodent pests when I took my master gardener education, I have to admit that having three “slayer” cats at my home garden meant I probably didn’t pay as much attention as I should have to that module.

If you also have something nibbling at your garden, here are some clues to identify the culprit.

Voles are vegetarian and have short, stocky bodies covered with brown, reddish fur and short legs and tails. They eat plant roots and grass and make the surface runways which I encountered at the garden.

Voles will also make one-inch holes to access bulbs as well as cause damage at soil level to tree and shrub bark where you will notice side-by-side grooves from their teeth.

On the other hand, moles have large snouts and paws, perfect for digging in search of grubs, earthworms and insects, as they are meat eaters and not considered plant pests. They create closed tunnels with lots of mini volcano-like soil mounds, called mole hills, while in search of their food.

Whether you suffer from either or both, please do not resort to pesticides in an attempt to rid your outdoor space of these pests as that can have far-reaching implications and travel up the food chain. You could be poisoning the very predators that are so necessary to keep these populations in check.

Rumour has it neither voles nor moles are fond of castor oil, which is available in either liquid or granular form. So you know what’s next on the shopping list. We may set traps in the garden in an attempt to rid ourselves of the problem.

Like any rodent, both voles and moles are extremely reproductive, so we have a challenge ahead as only last week a vole ran between two of the volunteers.

We will keep you posted on our progress, or lack thereof, and hope that by making the garden less hospitable for rodents we have a start on solving the problem. If anyone has some success stories, please share them.

The Okanagan Xeriscape Association is grateful for the ongoing financial support of the Okanagan Basin Water Board and is proud to be collaborating with them on their Make Water Work campaign.

Sigrie Kendrick is a master gardener and executive-director of the non-profit Okanagan Xeriscape Association and can be reached at 778-363-8360 or by email at [email protected].

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.