I think the shade factor would be more important than the PH. Most pines are going to drop needles which are acidic. But I don't think roses wont growin acidic soil (otherwise they wouldn't grow in my yard).

Pines are also shallow rooted and I think the competition for water could be a problem.

I grow a few under or next to pine trees. There is a lot of root competition. As long as they get 6 hours of sun daily and lots of fertilizer they'll grow. The extra water and fertilizer will also cause the pine trees to grow.

I have a noisette that grows 30 feet up a slash pine. I just make sure, like Karl said, that she gets plenty of water and food. She blooms well up the tree where she has spread out on the branches. Our soil is very acidic and it's not been a problem for this one.

For the record, as your message states, these are Doug Fir trees not pines. The southeastern posters have never seen a doug fir before I'm sure. Not every conifer is a pine. Pines are rare around here actually. As one of my natural history books says, if you're in western WA or OR, and you're looking at a tree, 90% probability it's a doug fir. Pseudotsuga menziesii. Not Pinus. It does make a difference in how you garden under them.

The issues are, shade and root competition. Yes the soil and leaf litter under a doug fir will be acidic, but the soil is anyway. pH below 5 is not uncommon here. Hardly anything grows under doug firs and red cedars (Thuja plicata) because their roots take all the water, and their canopies shade out all the sun.

You're supposed to plant your tree climbing roses towards the edge of their branches and let them scramble up the branches, not the trunk. I once planted a Paul's Himalayan Musk under a small and scraggly doug fir, on the sunny side, and tried to keep it watered. It struggled for years until I moved and now it's probably dead without me there to haul water to it. It did grow, and bloom, some, but it kept reaching away from the tree.

What does grow under doug firs? Take a hike and see. Sword fern, deer fern, lady fern; red and evergreen huckleberries; snowberry; blackberries; red flowering currants; salal and creeping mahonia; rhododendrons and azaleas; vine maples; wild ginger; trillium, fairy lanterns, false solomon's seals. Oh, and the native roses: R. gymnocarpa mainly as it likes shade, and some R. nootkana and R. pisocarpa, but they need more sun.

My little greenbelt of 40 yr old doug firs is filled with salal, hazelnut, huckleberries, blackberries, indian plum, cascara, snowberry, serviceberry, cotoneaster, rosa gymnocarpa, mountain ash, big leaf maple, and english holly. It's pretty dense. The birds love it. I stuck a couple rhodies on the edge, and a rosa nootkana but they're struggling from too much root competition.

And in any case hardly anything chooses to grow directly under a doug fir, near the trunk, except ferns. And nothing needs a specific pH, or nothing would grow anywhere.

So, perhaps the original poster needs first to determine what sort of tree he/she is dealing with????

Jeri

So sorry. Me dummy. I do believe that these are fir trees and not pines. Thank you for all of your info. I am going to pass it along to my friend, just so he knows what he is up against. Obviously, I had a brain f@#t when I was typing the subject of the posting and the message. Thank you for pointing it out. It does make a difference. Best regards, CJ