Roots can extend outward about 2 to 3 times the distance from the trunk that the canopy does, it is said. So if your 15 foot specification is based on the septic tank distance, consider that. I believe I read an online article on a 'Thundercloud' purple-leaf plum chronicling a woman's experience with it, and I think it produced that sticky crud due to aphids on things underneath; might want to check whether that's a common problem. I'd almost be leery of most anything 'maple' near a septic tank. When you say a taller tree is okay if it doesn't get over 15' wide, are you walking radius (from the trunk) or diameter (of the whole canopy)? Richard.

Thanks for the suggestions! We don't like grasses in the yard, especially after helping our neighbor get rid of some really, really invasive grass that Urban Gardener planted in their yard this past year. We have a lot of shrubs in the area already, and are looking for something more low-lying (less than 2"-8" tall) to fill in. I've never really had a thing for mondo grasses, but we all have our loves :) Between the three spreaders/clumpers above (veronica, epimediums, partridgeberry) we should be able to work something out to cover at least 60-70% of the area in question, which would mean 60-70% less weeding, and something to keep the ferns company during the winter when many of the other things have died back. I don't mind spending $$, I'm totally fine with that, but ... I don't want something that is a tiny 6" clump at full size, else we will be seriously spending a thousand dollars buying 200+ plants to fill the bed. Are the three aforementioned species relatively safe to plant near perrenials that die back down to the ground every year and re-sprout, or will they choke those out? If it is not safe, what kind of spacing should I be trying to maintain between these and other plants? (i.e. would the average spread diameter + 6" buffer be adequate?) I am normally really wary of non-native species, seems like most of the common ones are too invasive for my liking, which is why I had to ask. Search was turning up a ton of results, but I couldn't seem to refine it enough to find meaty info. Thanks again for the advice! BTW - Epimedium warleyense and versicolor flowers both look amazing! (see pics halfway down page)

I don't think it's a good idea to plant any tree near a fence. The problem is that as it grows, it may end up actually hitting the fence, possibly causing damage to it. Also, you end up with part of the tree on the other side of the fence, so it's difficult to take care of it. And if you're planting fruit trees, your neighbor may not like the mess when it starts dropping fruit in the lawn (although the ability to pick fruit without needing to pay for the tree may mitigate that).

re stumps - in the woodland area, I wouldn't be in a big hurry to get rid of them, other than to cut them down as low as possible. It can get very dry in woodland conditions. Rotting wood will hold a lot of moisture so planting new things next to a rotting stump or log can really help with survival when planting in an area where you might not be able to get to with a hose. We had a dead pine and a sick pussy willow taken down last fall. When we planted a new 'Wolf Eyes' dogwood to replace the one that died last winter, we planted it next to the pine stump to give the dogwood a source of moisture and nutrients. We put some logs from the dead pine on a dry bank at the back fence so the logs can hold moisture for the things we try to grow in that area. We moved our 'Empress Wu' hosta to beside the willow stump for the same reason. There are other logs, a dead apple tree trunk, and a few dead branches scattered through the woodland beds as moisture and nutrient sources for the plants. So I'd only grind out or otherwise remove stumps from areas where you want to grow lawn but definitely leave them in the woodland area - and maybe even in 'garden' areas too depending on what you want to grow there and whether it would be useful to have a natural moisture sponge and nutrient source for them. There used to be a big old white spruce where our big front bed is. When we had the tree taken down the stump was left, cut off at ground level. It's rotted away completely now and the soil in that area is better than in the rest of the bed!