Hello,

Do check for vole feeding. Trace the browning branches back to the ground...do you see any chewing on the shrubs? If so, then the voles chewed during winter and the shrubs "crashed" as the plants woke up this spring.

Set out unbaited mouse traps, placed end to end, in active runs. Cover the traps with a piece of gutter or other tunnel. 

You can also try using Milorganite around your landscape. It's been found to have deterrent properties. Use 15-20 pounds/1000 square feet. Water in well. Reapply every 4-6 weeks. 

Hi John,

Yes, that's voles that have chewed the bark. They essentially girdle the branches by feeding--they might be looking for nutrients? Water? 

Set out unbaited mouse traps, placed end-to-end in their active areas. You don't need to use any bait, as they will run over the traps. Cover exposed traps with a piece of gutter.

For the junipers, your only option is to prune out those dead branches...they will not recover. Vole populations are cyclic, so hopefully they will crash soon?

Hi John,

I am working remotely and only get the office one or two days per week. Sorry I missed your call. 

Milorganite is readily available at stores in the Loveland area, if you drive down from Estes. I've seen it at Walmart, Bomgars, Ace Hardware, and Tractor Supply. It's an organic fertilizer that is from composted sewage sludge from Milwaukee. It's been used for decades. Here's a publication from Cornell that would be a good read: https://ecommons.cornell.edu/bitstream/handle/1813/2858/Milorganite.pdf;sequence=3

To answer your questions:

1. It's a known repellant. It will not kill the voles but will repel them. They will move elsewhere. It's also been found to be an effective repellant for rabbits and deer.

2. I have never made a bleach-soaked rag recommendation; if this was recommended by our office, it was not based on science or research.

3. No, mothballs will not be effective.

4. No, the cat litter will not work.

You can simply learn to live with the voles and the damage. Prune out the branches as they die back. Again, voles are cyclic and their populations will eventually crash. We have ebbs and flows of damage.

Good luck!

Hi John,

See the following articles from the U of NE:

https://digitalcommons.unl.edu/icwdm_wdmconfproc/182/

https://digitalcommons.unl.edu/icwdm_wdmconfproc/179/

We have suggested this as a repellent to people and they have confirmed that Milorganite does work. If you want to try the other methods, you can. I am simply recommending research-based recommendations. You would apply 15-20 pounds/1000 square feet and water it in. Reapply every 4-6 weeks, depending on how much water/irrigation the area gets.

But it sounds like you have extreme concerns using this product, so below is our CSU Extension fact sheet that lists other things you can try. The castor oil products have not been tested or proven to be effective. 

And the CSU Extension publication (which was last updated in 2015, prior to the U of NE research): https://extension.colostate.edu/topic-areas/natural-resources/managing-voles-in-colorado-6-507/

See the section under "Repellents" for additional options. 

The cycle depends on the populations...it may be high for 3 years and then slow. It all depends on predators and how successful the litters are. There are studies that show that the male voles become sterile once populations are high so reproduction slows. The problem is is that voles can have up to 12 litters per year.

And yes, while you have active vole populations, your junipers are at risk--they are a food source.