Prevent hop roots from spreading around

[Suicid]

Hi folks,

There are second year hops I have here in my garden and I am a bit concerning about roots.

How do you guys usually constrain those?

 

[Yooper]

I don't/can't. My 8 year old cascades are popping up under my deck, and trying to spread. I just mow the grass around them, and pull them out from under my deck. You can trim the crowns, and that is recommended, but they still will be invasive overall.

I grow 8 varieties, and I have them far apart to keep them from mixing.

 

[GilaMinumBeer]

When I grew them, I built large 48"x48"x18" above ground cubes for each crown. 13 in all.

I still found roots popping up outside the cubes.

Only way to contain the root system is to grow in containers.

 

[B-Hoppy]

You really don't have to concern yourself with the roots as they can't produce new growth (under normal circumstances). The rhizomes are what you have to keep in check and they are what you purchase from a supplier to start your plant with. They're a specialized underground structure (different from the roots) that contain vegetative buds and are generally found growing horizontally away from the crown and are usually within the upper 5 or 6 inches of the soil as opposed to the roots which pretty much grow straight downward. If you stand directly above your plant/crown and look down at it, the rhizomes will grow outward from that point like the spokes on a bicycle. As long as the plants are growing out in the open and not up against some sort of barrier and you can dig the entire 360 degrees around them, you can remove any unwanted growth on a yearly basis and keep them from spreading. If, after you do your annual spring thinning, you happen to see some new shoots coming up in the vicinity, it's usually just a part of a rhizome that you didn't get. If you pay attention and dig these up as soon as you see them starting to sprout, you can keep them in check. If left unattended, they may be able to get established and will be that much more difficult to get rid of in the future.

This doesn't pertain exclusively to hops but is a good place to start: http://www.biology-resources.com/plants-vegetative-reproduction-01.html

Here's some more info on hops in general: http://faculty.agron.iastate.edu/fehr/HOCP/27HOCP.pdf

 

[coneal]

I've never grown hops but I do have mint plants and they spread like crazy if unchecked. What I did for my mint was built a square out of 1"x6" (or 8" - don't remember now) cedar planks and planted the mint inside that. I buried that "bottomless box" so that only an inch or so was sticking out of the ground. What I always thought were the roots have to go over the wall of the box for the mint to spread. As soon as I see one, I cut it back. And then I toss it back in as a warning to any other plants thinking of trying to escape, but you probably could skip that.

I do get mint popping outside the mint garden occasionally, especially after vacations and such. When it happens, those plants are weeds by definition, and get treated accordingly.

I'm not sure if that would work for the hops, but it seems like it would. Try searching the internets for "controlling invasive plants" or something like that to get a better recap of what I did.

 

[GVH_Dan]

Similar to coneal's "bottomless box", I have taken the largest plastic garbage can I could find, cut the bottom out and put the hop inside that. I would have a few inches sticking out of the soil and at least a foot below. It seemed to contain them but you still have to clear the rhizomes out because it gets quite crowded in there.

I do like coneal's idea of tossing the clippings back as a warning, except they would probably sprout.

I've also hear that four speed limit signs welded at the joints does a really good job of containing them. I've only heard...never tried.

 

[damdaman]

You can buy rhizome barrier, usually used for containing invasive bamboo, and install it prior to planting. The stuff is expensive and it's hard work digging a trench for it, but it's very effective.

 

[Suicid]

Thanks, guys, for all your advises.

And then I toss it back in as a warning to any other plants thinking of trying to escape,

I've also hear that four speed limit signs welded at the joints does a really good job of containing them. I've only heard...never tried.

Need to tell this to my neighbour who is planting mint

I am most likely going for bottomless box/can then.
What the minimum dimensions should it have for lets say 1 vine grows ok? From your replies I've got impression ehat 1 foot depth might be enough , but what about diameter (or w/h if it is rect)?

 

[GVH_Dan]

I would go at least 2 feet down. Once the rhizome hits a wall, it doesn't just stop. Just to be on the safe side.

Width: go as wide as you can. I've grown hops in 2 foot diameter pots that were pretty tall and they were definitely stunted. If you can get to 3 foot diameter with a bottomless box, you shouldn't see any effects on its production, but this is somewhat a guess. I've never really studied the productivity of my backyard hops. Just try to get rid of the rhizomes every 3 years or so.

 

[sumbrewindude]

I tried to contain them above ground last season - 1st year plants.

I used 55gal blue drums cut in half, (ended up being just over 2'), and drilled small drain holes in the bottom, and lined the barrel end with weed block before putting the dirt/rhizome in it. I then placed it on the ground directly next to my support system so it could drain normally.

Over the course of the season things went great, had good drainage, etc. When I went to pull the half drums at the end of the season and get them up by the sheltered garage, I couldn't move the barrels. The tap roots(?) or something had penetrated the weed barrier and gone down in at least a good two foot into the ground and were promptly ripped out when I got some help to move the barrels.

I was VERY surprised at the size of the tap root (?) for certain varieties vs others - for example Chinook only had 1, maybe two but they were easily as thick as my thumb. Cascade on the other hand was a disaster with roots out everywhere through the drain holes and they had no interest in going down so much as spreading outward from the barrel.

All said and done, I dug out almost a 5gal bucket full of these roots from under the barrel spots as the last thing I want running down my fence line are six different varieties of hops. I'm sure I didn't get them all, but I'm not overly concerned considering the size of the roots that I couldn't get out (less than an eighth of an inch diameter).

I like the barrel idea because I can move them when it's cold or move them along should I get tired of it. I need to figure out how to deal with the penetration of the weed guard issue.

* I say tap root because I'm not sure what the heck they were - they were definite roots, and didn't look anything like the rhizome that was initially planted.

Garbage can minus bottom is a solid idea, but digging the plant/rhizome out later could be a challenge.

IMO.

 

[sablesurfer]

Yep, containers here too and second year, when I went to move them up against house at least three had found the drain holes and established some decent roots down.

I am thinking about a raised bed this year and considering the whole dig the crown out thing once in a while. <shrug>

 

[Brewer Gerard]

From a plant health point of view, is there any benefit from stopping rhizome spread?

 

[damdaman]

From a plant health point of view, is there any benefit from stopping rhizome spread?

No. The plant actually needs to spread to continuously create new underground growth, which is healthy. So if you contain it in any way, you should dig it up and prune the roots back every 2-3 years so that the roots have room to grow again.