I think your friend's explanation is the only one which makes sense. Roses generally have very deep roots, and you seem to be doing all the right things.

I think the top foot of so of almost any soil is where most of the oxygen, the water and the mineral nutrients are concentrated and that's where most plants, not just roses, have most of their roots. For example, one widely quoted statement is that all trees grown by homeowners have 90% of their roots located in the top 12 to 18 inches of soil. Roses and other plants do have heavier roots which can go very deep in the soil. I'm convinced these deeper roots serve mainly to anchor the plant.

In most garden soils, the deeper you dig, the drier the soil. I think a self-sufficient rose would be one with a more extensive and more concentrated system of shallow roots, not one with deeper roots.

Don't you think this has something to do with soil type, climate and water supply, and rootstock? And with everyone's idea of shallow vs. deep?

I've dug up roses from excellent, well-drained loamy soil, and the roots were not concentrated in the top 18 inches of soil. But then those roots didn't need to stick near the surface to seek oxygen in the wet season or water in the dry season. I could see roses that survive in very cold climates adapting by having very deep roots that are freeze-protected by soil.

I've also dug up seedlings. They as a rule have a long carrot root-shank, which is why they are used and excel as rootstocks. A tiny rose six inches high can produce a prodigious carrot root that goes straight down with a shank six inches before it even branches. They survived 6 months of no water in our annual drought precisely because they had that ability to seek water in the deeper soils that are heavy and hold water longer.

Last, I've been collecting native species, and they definitely live in the top 6 inches of the earth's surface. California species are largely thicket-forming, spreading by suckering. The rhizomes live in the litter and mulch, barely in contact with the soil, dropping a few rootlets here and there. It's like one large field of Bermuda grass, all one plant spreading out from the center in the mulch, seeking soil.

Melissa, are your roses on laxa or multiflora? Laxa may be the deepest-rooting rootstock, from what I've heard.

Different rootstocks have different patterns-- it's easy to tell Manettii from multiflora from Dr. Huey bareroots by their different structures. Soil texture and irrigation will also make a difference, and age of the plant. However, I've seen old Manettii roots that were not irrigated (a park) and that were adequately drained stay mostly very shallow. My own roses are shallow rooted because there is no deep soil. They do OK.

The roots are probably in proportion to the size of the bush. If they need to go farther to seek more water and nutrients then they will. But also the mycorrhizae fungus will attach to the roots and extend their effective nutrient and water gathering. Genetics probably plays more importance than anything as to how large the roots get. Some prairie roses are said to put out roots 20 ft. But i think most cultivated roses are relatively shallow in comparison.

Probably a third to half my roses are on their own roots; I believe the rest are grafted on laxa. The own root roses are a mixture of Teas and Chinas, Hybrid Musks, English roses, once-blooming old roses. The soil is either clay or rocky and poor, in the latter the roses don't do that well. It's all sloping. In the clay they can hold on forever, and I'm pretty sure that there's water below the surface there.

Thanks to all for the input. Berndoodle, thanks for the excellent discussion.

Melissa

I moved earlier this year and dug up a dozen (only; of 250-300 established plants) to take with me. All of them are own root. It was very difficult digging, and I lost at least half of them anyway, precisely because roses are NOT shallow rooted plants. You should have seen the roots on my Crepuscule (gone) and Climbing Shot Silk (also gone).

I guess deep and shallow are relative terms. By contrast to roses, azaleas and rhododendrons have classic shallow roots and thus can be transplanted just about any time. Nothing deeper than 6"; and very wide spreading. They rarely blow over, as roses do when young, because they have that nice wide root base to sit on. Not so with roses. I won't deny there are feeder roots up higher, but the overwhelming mass of rose roots head more or less straight down.