Anything is possible as long as you keep the clematis well watered. Maples are notorious for sucking moisture out of the ground but paying special attention to the clematis waterwise should counteract the maple's tendencies. You have to decide how meticulous and consistent you are as a gardener to determine if you want to plant the clematis there or somewhere else.

Thanks for the reply. I tried to dig there, the soil seems to be wet enough. It is our regular Maryland clay, so I will have to ammend it. I am afraid that the tree roots will suck nutriens also. Of course, I can water and feed my Clematis to keep them happy. I think I will give it a try. If they will not feel good there, I can replant them, right? I will have to restore lawn after that, but it sounds doable.

I haven't tried it but someone posted not long ago about combating roots by burying a 5 gallon bucket where they wanted the clematis, cutting the bottom out of the bucket and planting the clematis inside the bucket which keeps the tree roots outside. It sounds good to me but if I try it I will probably use a larger container.

Thanks Bob. The problem is that Maples' roots are very fine, so only solid pot will work this way probably. I am not an expert, but those damn roots look very fibrous. It seems that they will be able to get into any basket.

I'm thinking maybe one of those 15 gallon plastic nursery pots with the bottom cut out. The 5 gallon bucket may be large enough.

I personally don't see how planting a clematis in a bucket with the bottom cut out would solve anything. By putting water in the bucket to water your clematis, you would be enticing the roots of the maple to dive deep and then come up into the bucket to get to the water source. Then the clematis will really have to compete to get both water and nutrients.

I think I will dig the hole deeper and wider than usually, fill it with the good soil and plant my Clematis. By the time the Maple's roots will reclaim their space, the Clematis will be established and strong. I will also monitor it constantly. If it will suffer, I will replant it.

I hope this plan will work. What do you think? All my Clemmies are potted, so I do not have any experience of growing them in the garden.

Is anything else growing around the maple? Is there grass growing under the maple or are there shrubs within 10 feet of the maple?

Grass is growing right under this Maple, very close to the trunk. Nothing else is. We have these Maples planted along the street, same pattern: grass only. Maybe, people did not try to plant.

Red maple is not as bad as silver maple, but I still have visions of watching a hosta go from lush to barely alive in about 2 weeks, an azalea took about a week and a half to succomb, and lamium would grow, then parts of it would die almost over night. What will happen is the fine feeder roots will grow into the moist, amended soil, entwining with the roots of whatever plant is in it's way. The difference between the red and silver maple is the speed at which the roots grow, but I've heard of people having trouble growing other plants underneath japanese maples.

If you decide to try it, notice if there are a lot of roots that you dig out, if there are, they will surely grow back.