How likely is it that a gopher will eat all of the roots off of my 4.5't, 6-8'w, variegated American Agave?
It has already eaten the bottoms off of 3 out of 5 'pups'. I'm not complaining as I was going to have to move, or remove, them anyway. But, at this point I am wondering if the gopher is going to take care of the cutting the leaves off for me! (;
I know 2 men who removed a clump of them together once, and while one of them had no noticeable reaction, the other person had an extremely unpleasant reaction that lasted for some time, I guess to the sap, or the poison in the tips of the spines. So . . . I am hoping to be 'spared' having to work closely with this plant! (I read about the experiences of several others on 'DG's American agave page.)
Larger size and correspondingly larger root system makes it less likely for them to eat all the roots vs a smaller plant, but it's not impossible. They killed a 6 ft tall well established Anisodontea shrub in my garden this past spring by chewing off enough of its roots. It was something I'd planted when I first bought the house and didn't realize I had gophers yet--since I found out that the gophers will be all over the back yard I always plant everything I care about in wire baskets.
I have many large agaves (4-5 ft high) on the hill behind my house and the gophers eat at least three to four of them each year. They eat right up through the center and the plant just collapses into a pile of leaves. They are more active in the winter here when the ground is wet and easier to dig.
I have large Aloe veras that the gophers eat up through the center of, too. A few a year. They can be re-rooted, supposedly from even the leaves. I hadn't believed that they could re-root from the leaves, but one I re-rooted came out with a double center, and the only way I can fathom that it would do that, is if the leaves are re-rooting separately. . . I've never heard of Agaves re-rooting from the leaves, though.
I call an exterminator. You can buy stuff to do it yourself too but I've had better luck when the exterminator does it. (I don't like using poison bait because I wouldn't want my dogs or the neighbor's cats potentially finding a poisoned gopher and getting sick themselves--the stuff my exterminator uses is pellets that you stick in their tunnels and when it gets wet it releases a gas that kills them, but doesn't leave poison behind in their body like the baits would)
If you go over to the California Gardening forum, there is a huge long thread over there about gophers so you will find many other tips there.
We have a crazy gopher and mole problem at my house Northern CA because we live next to an open space. We tried everything to manage it ourselves and then had to call in a professional. I'm going to be doing a lot of xeriscaping of our yard and plan to put some type of cage around the roots of my larger/ more expensive plants so that the gophers cannot damage them.