You could put a root barrier of some sort (they make them for running bamboo) along your fence line, though this would be a lot of work and the barrier is not cheap. A cookie sheet would not be large enough--the roots would just go around it.

The other option would be as you said, submerge large pots into the ground, and check them yearly to ensure that tree roots are not growing up and into the pot. Do not go too small on the pots, so that the roses have room. Also the pots must have holes in them, for good drainage. I think that would work. We did that at the old house near a pine tree.

You might consider root control bags. They have a copper lining, which repels tree roots. The tree roots will not grow through the material. You would basically be planting the roses inside the bags, which would limit how big the roses' root systems could get, but at least they wouldn't be fighting the tree roots.

I don't think pots are the best option. Been there, done that. Aggressive tree roots will grow into the pot holes in less than a season.

Deanna

Here is a link that might be useful: Root Control Bags

By the way, I meant to mention that a raised bed will not prevent the roots either. The roots will grow up into the raised bed. Additionally, tiny little feeder roots will find their way through the tiniest crack in any barrier you try to erect. They manage to grow into the sewer pipes that go from my house out to the main sewer line, causing backups in my basement every few years.

I have a lot of experience with this! I live in a neighborhood with lots of large, mature trees.

Deanna

Dear Deanna,

Thanks so much for suggestion of root control bags! Today I collected 7 gallon, 10 gallon, and 15 gallon plastic squat pots from local nurseries and realized I would have to dig huge holes for them. Plus, as you pointed out, tree roots can still grow into the drainage openings. A Home Depot manager suggested laying a subterranean wall of concrete along the property line, but this solution is truly beyond my means at this time.
The root bags sound promising. Even though the bags can limit the size of the root system, I think they will be fine for my smaller hybrid teas such as Velvet Fragrance and large minis (Liberty bell, Ambiance). Hot Cocoa will probably be restricted, but at least it will stand a chance of living and blooming.

Question: when using these bags do the rose roots need any additional protection to prevent the bags from tearing? Would planting a bagged rose in a submerged pot be a good idea? Or, can I simply put the bagged roots into the rose hole, and the bag will expand underground as the roots system grows? I hope it is the latter!
Have you had good results with these bags?
Thanks,
jmac

Rent a Ditch Witch and dig a trench right on the lot line as deep as you can but a minimum if 3 feet. Then get a roll of plastic like that used around above ground pools. It's thick and if there are no holes in it, the roots won't penetrate. Allow a few inches to stick out above ground so roots don't travel over the top.
Any portion of a tree or shrub that grows over the lot line is fair game and you can remove it. This includes overhanging branches and roots.
Metal sheets will rust and if they are not one long continuous sheet, tiny roots will grow through where they overlap.

Just forget about the pots and plant them in the bags. Dig your hole, put the bag in it and spread it out and backfill with dirt and your rose (and compost if you normally use that) like you would if you were planting in a normal hole. Leave about one inch of the bag above ground to make sure there's no place for the tree roots to get in. Since you're planting roses, I'd get the biggest size bags that website sells.

I haven't used them, but Esther Opal on the hosta forum raves about them.

Deanna

Thanks everyone for these suggestions! I'll probably take a combination approach of root control bags for new plants to provide immediate relief and and some type of barrier perimeter as another line of protection, especially where bags are not feasible.

Regarding the root control bags, I'm going to the manufacturer's website to track down a larger size. The 10-gallon size is probably fine for my large minis, but it will be too narrow for large normal roses (considering the lateral spread of their root systems).
Thanks again everyone!

Jmac, I feel for you. I have invasive roots where I am, too. huge elm tree directly across the street from my front yard that sends roots all the way across the street. And 2 big elms behind my house at the property line with the neighbor. My first thought was what Karl preposed. But if that is still too big a project, you could opt for what I do. Grow everything in pots above ground. The down-sides are frequent watering, the "look" of pots, and you're more limited as to varieties that will be happy confined. But most minis do great in large pots. On the plus side, you can much more easily defend them against invasive roots, its much easier to transplant and move them around, which I like to do, and some roses actually establish better in the protected confines of a pot for the first couple years, anyway. It's one option to think about.

I'm not familiar with the copper bag thing. How does one manage drainage with that? Roses certainly need unimpeded drainage! Can someone clue me in? (scratching confused head)

Mike

Hi Mike,
I've learned some more details about the root control bags since my original posting. They are air and water permeable and were created for commercial tree growers who need to keep tree roots neatly in bags. Gardners who want to protect plants from invading roots can turn the bags inside out. The copper-infused resin surface is just on one side.
This link will take you to bag specifications:
http://www.texel.ca/imports/pdf/en/agrotextiles/TEX_Fiche_Agroliner_BR.pdf

Because I'm planting in clay, I have to amend the soil around the bag somewhat to enhance the flow of water out of the bag. Also, filling the bag with the type of soil or potting mix that promotes drainage will help water escape from the bag.

Horticulture Specialties in Michigan carries the 20-gallon size which is deep enough for a full-size rose. It's probably a bit too deep, but the 15-gallon bag may be too short at 15", considering you want to keep an inch of the bag above ground. I think the 20-gallon size will be wide enough for the root system. You can shorten the bag by folding its top down or cutting it off at the top. These bags can be used as a submergeable pot. You can pull them out of ground, which is convenient if you want to relocate a rose.

Horticulture Specialties in Michigan carries all the different sizes.
http://horticulturespecialties.com
Jay Adcock is extremely helpful.

The root control bags are also called root grow bags. Look for the Tex-R brand.

Interesting. Seems that would confine the rose roots to the same space as a large pot, the main advantage being all the heat insulative quality of the ground around it. I still think I'd avoid super large rose varieties.