I have a major vole problem. I would like to grow as many caster bean plants as possible to see if they will help. The caster bean oil is not.
I don't care if they act like an annual. Their roots will still be in the ground and act like a repellent hopefully. I can grind, or chop the limbs and leaves and add to the soil also.
What variety will be best in zone 8a? We just changed from 7a to 8a here. Thank you in advance. I am pretty desperate.

Trinna

Not sure that growing castor beans makes any difference...
I've planted castor beans and still seen tunnels near the castor plants.
I've inserted the beans into the fresh tunnels, and the only difference I saw was when the beans grew.

I doubt that it's going to make a difference what castor beans you plant... Probably going for showy would be a good choice...

I have cats, they kill the voles.
Unfortunately, the cats kill everything that moves... so... maybe look into trapping the voles?
The thread "Daffodils as a Vole Repellent" in Ask a Question forum

Thank you so much for your quick reply. I have purchased the caster oil liquid to spray and have sprayed heavely several times, then followed with a bag of the caster dry mix. The voles don't care. I have put the flares in the ground. The voles don't care. I have put the traps in the tunnels on both sides on top of the vole exit holes with peanut butter and oats. They are not interested. I have bought the small rough rocks and poured them around the plants but I think they are using them to sharpen their teeth. I have tried several poison pellets and that has worked some but I am out numbered and cannot get ahead of them. I have bought a nice pitchfork and have been stabbing the tunnels. Now I am sure my neighbors think I have gone insane.
I have planted my garden plants that I love. Now that they care about, and love them also.
So nothing is working. I have been fighting them for 5 yrs. and my yard is still riddled with a tunnel freeway system.
I have contacted several snake removal services and hope I can buy some snakes from them. But the immediate problem and the voles are very active eating everything and making babies and the snakes are sleeping. So when they wake up and start scaring people, maybe I can be the proud 'owner' of some vole killers. I am having trouble finding info on how to introduce them to my yard and how many snakes can be in an area with each other. Right now I think I need about 6!
This is a horrible situation for a gardener to be in.

Its not the right time of year for Castor Bean to be growing, Its a Spring through fall plant, it seeds and dies back in the winter. You'd have to try it later in the year

Oh yes. I know that. I am not going to grow them. I don't think they will work. I was going to put the seeds in the tunnels this winter in hopes they would not like the smell, but since Stone said he did that and they grew into plants and did not bother the voles at all, I am not going to do that. So I am done with the caster oil. I will finish off the gallon jug I bought since it cost so much money, but I don't have much confidence in it.
Unless anyone has any ideas my only hops is the snakes. I am however going to keep the mouse traps set. Haven't caught anything as of yet.

Thank you!

Snakes are territorial. That means they might go back to where ever they came from.

How about a pack of terriers?

The cats are actually doing a good job for me...
When I see one with a lizard, snake, or bird, it makes me unhappy... but I am able to grow a lot of stuff that was impossible when I first started gardening here...

So... do you like cats?

Maybe encourage some feral cats to hang out...

When I was first here... a momma cat showed up with a couple children... she left one when she moved on... I really wanted them all to stay... but feral cats have lives of their own...

A pack of Terriers sounds terrifying! Lol I have no animals. Love dogs, but not the cost and responsibility. My neighbor's cat hangs out at my house. He is useless except for catching birds which is exactly what I do not want.
The snakes will be brought from people who remove them from other's property. That could be from other towns. I don't think they will leave if there is a good food source, which there is. But I do not know for sure. I will learn more about it however.

Thank you all so much.

Welcome to the critter world. For several years I battled the very same problem with gophers in east Texas. A couple times I actually got rid of all my gophers, but every one of my neighbors had them, so I could not clear the area.

I have watched gophers dig directly under my young castor plants and push them up on top of their tunnel. I have let castor plants grow "wild" for multiple years in places and had as many gophers there as everywhere else. I hooked up my mower's exhaust to tunnels, put juicy fruit gum in tunnels, put gopher bait in tunnels, trapped and killed many many of them, shot many of them with a gun, poured bleach into tunnels, put propane in tunnels and ignited it, and even talked ugly to them. All in vain. Your pitchfork might be the best option if you can't keep a cat.

MY terrifying terroir has never caught anything!

I lived in San Diego county and got really good at gopher hunting. I would pick them off from the house with a pellet gun. Then they put there little berms between them and the house. Smarter than I thought. Their tunnels are larger and easy to dig up and put traps in. I got really good at catching them. One of my last thoughts in driving away after selling the house was, I am really glad not to have to deal with the gophers anymore. I was free of the war. Then I bought this house and it is ten times worse. I guess there is no answer to this problem. I have done a lot of work in my yard. Invested in a lot of plants because at one time I thought I had solved this problem. I was wrong. Now I am not sure what to do. They have tunnels all over the yard. Cannot hardly make a step without collapsing a tunnel.
I am in NY now. Left 6 traps. I hope I come back to some dead voles.