Ecology Bum Experiment: Controlling Bush Honeysuckle with Salt

OK people, time for an Ecology Bum Experiment! As many of you know, controlling invasive species like bush honeysuckle (Lonicera maackii) can be difficult. Cut 'em, burn 'em, mulch 'em and they spring right back up from the stump! Most sources and professionals will tell you that treating the stump with herbicide (glyphosate or triclopyr) after cutting is the most effective method to keep honeysuckle and other woody species from regrowing. There is no doubt that this method works, but I was curious about alternatives for those who get a little nervous about using chemicals or don't have herbicides on hand.

After doing a little research I found some information about salting stumps to kill woody vegetation. So I gave it a try! I had one large bush honeysuckle plant that needed killing so I had a subject to put this salting method to the test. 

This bush honeysuckle specimen in my backyard avoided the mower by growing along the fence-line. The dense foliage of this plant prevented much of anything from growing within 3 feet of the trunk, creating a large patch of bare ground. This individual acted as my test subject. 

Here's what I did about two weeks ago:

1. Cut the stump

Ahhhh! Makes me feel better already! Taking your yard back is like scratching an itch on your back; it sometimes feels out of reach but sure is satisfying once you dig your nails in!

The stump of this mature bush honeysuckle shrub was ~8" in diameter at the time of cutting. 

2. Drill 8-10 holes in the cambium layer of the stump

Holes allow the salt to penetrate deeper into the stump, facilitating the spread through the root system and preventing it from being washed away during a heavy rain. 

I drilled several holes 5" deep into the stump to prepare for salting. 

3. Fill holes with rock salt

Once the holes were drilled, I filled them with salt. This shrub had a significant amount of rotten core so I decided to salt that area as well.  

4. Plant native plants 

Of course once I had the stump salted, I was still left with a large patch of bare ground from where the honeysuckle had been outcompeting all the other vegetation. What to do? Plant natives! I decided to add a second wildflower plot to my yard in this area. I raked away all the leaves, needles, and sticks and got out the hoe. The soil was fairly loose already so my hoe made quick work of the area. Once the first 2-3" of soil was cultivated, I packed it gently with my feet, broadcasted some leftover native forbs and grasses and pressed them into the ground. 

Now all I can do is wait to see how well salting the stump prevents regrowth. Stay tuned for an update! If it works, I think this could be a good option for landowners with only a limited honeysuckle problem and a fear of herbicides.