I would say "NO" because that looks like primarily wood chips (high carbon) that will create a nitrogen deficiency if you mix it in the planting soil. Rake this mulch aside. Then get some good potting soil(at least a 3-5 gal pail's worth) & back fill around the rose. Now rake the mulch back around the rose & add more, if needed, to get a 3-4" deep mulch layer around the rose but keep it back 3-6" from the rose (keep the mulch on top of the soil, do NOT mix it into the soil). Water it in good & you're all set.

I re-read your post & you said >>> 6' X 33" hole

Wirosarian,
The rose is currently about 3' tall x 6' wide, but it is still pretty young. I expect it to get atleast 10' - 12'
wide with severe pruning when it's mature.

I have pure white sugar sand for "soil" (which is full of root knot nematodes)so I had a huge hole dug, and need to fill it with something that doesn't cost too much. Just a regular rose takes about 6 bags of
soil at about $7.00 a bag.
Do you think I could add something to the chopped wood mulch to compensate for the Nitrogen problem?
I have started using about 30% of this mulch mixed in with Jungle Growth in my pots as I move them out of bands.
So I hope there is something I can add.

If you add bloodmeal, that should compensate for the nitrogen loss from the mulch breaking down. I don't remember the ratios off-hand, but if you look up "green to brown" ratios for composting, you can use that as a guide. The mulch is "brown" and the blood meal is "green." When the mulch has broken down, nitrogen taken up from the soil will be re-released into the soil. I remember an Ashdown video about layering compost and mulch each year and mentioning how using a nitrogen-rich compost or soil amendment will compensate for nitrogen loss from mulch breakdown.

It would probably be great if you could find a horse ranch nearby. Mixing manure with that planting medium would probably work well.

:-)

~Christopher

Thanks, Christopher. I have a friend with a horse.
Now that I have a plan, I go to sleep and stop worrying. :>)

Gracin

This is a really bad approach. Wood chips and bark are not soil and won't become soil for years. In the process of rotting down, they will lose 80% or 90% of their volume. OM buried deep will decay anaerobically and stink like sewage, releasing toxic stuff like hydrogen sulfide. I'd suggest a mixture of 4 parts sand to 1 part clay (in the form of plain cat litter) with 3-4" of decayed organic matter added to the upper 12". OM could be leaf compost, composted manure, or bagged "soil" from the garden center.