The situation is mostly humid and cool zone 7 climate. Bud 9 apple rootstocks.
The Idea is to back fill the planting hole with 75% Large sharp gravel, 25% native soil. and possibly an extra layer of gravel as mulch. I will try some with more gravel, IE 5 gallons worth, and consecutively less until some are planted with 1 gallon worth in the ground.
The goal is to deter voles and field mice from making trails below the trunk area and eating the tree. Most mouse damage I have had is from below ground root access, not surface damage. So I want to stop them below ground with this approach.
I doubt there will be a issue of lack of water as irrigation and humid climate, also weeds will cover most of the surface before too long. I don’t think extreme cold is a issue in our climate. Most nutrients will come from beyond the gravel when the roots are farther reaching.
Is there anything I am overlooking?
A Image of what I think is just mulched gravel, but a similar end result I expect to see.
I seem to remember Michael Phillips recommending replacing gravel nearest trunk each year as a routine chore. I did the same but I don’t remember adding that much to the hole.
Here with my orchard in Western North Carolina, i have had persistent Pine Vole pressure. If your apple or other fruit trees are getting munched below ground it would be Pine Voles rather than mice or even Meadow Voles.
I have had to up my game from just hardware cloth wrapped a few inches below ground to a crushed rock/gravel layer under, around, and above the root ball in addition to hardware cloth a good 18 inches down. The voles here seem perfectly capable of digging fairly deep to get under just the hardware cloth so the rock layer is necessary to deter them.
In the photos you can see where I have used a can with the bottom cut out to use as a form to fillbthe gravel in around the hardware cloth. I then lift the can out leaving the layer of gravel between the root ball and the surrounding soil/vole zone. I have only been doing this for a few months but so far they seem to have made it through the winter…
Woah… I appreciate the dedication but am saddened by the amount of protection needed. Great photos to show the process. Thanks for sharing and keep us updated on how effective it is.
That is impressive, I have seen people doing this in germany with cardboard as the form, left in the ground and then small gravel filled in. I found that to be not good enough in theory because the small gravel can be managed pretty easily by the rodents as i have seen by filling their holes with it and compacting that in, they would just remove it as they wanted.
I think the large rocks like what you used is the best, I think to just invert that basically and put all the rocks up to the plant roots so there is really no place for the rodents to go. I have a hard time using metal mesh as I imagine a 5-10+ year old tree roots will get pinched or encompass that mesh which may not have a huge effect but i wont be able to really check it out in the future unless the tree dies. My wife used to do thin wire mesh cage around apple trees and some of those still had rodent root damage.
Generally the ratio is not too bad for rodent damage here, roughly 1/50 trees get killed. but I would like more insurance that the ratio stays low into the future.
Thanks for sharing those photos. I think that is a perfect addition to this thread!
I trap out the pine voles on my land in fall when they will come to the surface for food. I bait the traps with peanuts and cover them with heavy trays gradually moving the trays over the extent of my nursery keeping them about 4’ apart. When I’m lazy or just too busy I will use poison bait stations but worry about my hawks.
I learned the ropes in S. CA where gophers were everywhere but which I would also trap out. The alternative was rat wire baskets (hardware cloth) which would assure that roots would only get pruned and not be eliminated.
Field voles can be deterred with simple plastic wraps around the base of trees.
So I planted about 60 trees today in a stone compost mix. I ran down the row with a mold board plow to open it up. dug planted and added tree tubes and stakes, later am putting in irrigation, metal posts and wire. I will continue to add more stones and compost to fill the holes this spring. Similar to what Osprey showed above but without the cage. I just put in a few shovels of rocks at the bottom then made space by hand for the plant, put in compost and more rocks around and on top.
Cost me about $10 for a trailer and the extra work was not so bad as i expected. So roughly $0.50 per plant and x2 so $1 when I add further stones as i bring another trailer load…
Someone told me this today also right after I finished in the field and showed him the work. Some types of glass i would say no thanks… nightmare for kids and hand weeding, weed whacker O_O…
It is interesting if using tempered glass chunks. I wonder if there would be a risk of toxicity since i would want to use a lot of material.
In a large commercial apple orchard I worked at years ago,
One bad winter with heavy snow we had a lot of vole damage.
I bridge grafted many trees to save them.
The University recommendation at the time to prevent vole damage was to put round “PEA “ gravel in a 2 foot circle around the trunk several inches deep . And put out bait in the fall.
The theory being that the voles could not maintain a tunnel in pea gravel , as it would collapse.
We did most of the orchard this way ,with pea gravel.
Seamed to help a lot.at least protected the roots. Had some girdling above the gravel in following years with deep snow.
Towards the end of that project, the gravel yard ran out of PEA gravel.
So we used CRUSHED limestone instead to finish.
The trees were on MM 111 and MM106 rootstock.
The MM 111 with crushed limestone did well.
We did have A HIGH mortality rate with trees on MM106. Using CRUSHED limestone
The university said it was from collar rot .due to the MM106 being more susceptible to collar rot ,and presumably the sharp crushed limestone causeing wounds at the base of the tree as the wind blew.
MM 111 did fine with crushed stone ,as did all the trees with the small rounded PEA gravel.
So caution is advised.!
