I have some questions about landscaping around a sand mound.
We live in Central-PA and bought a house with a sand-mound in the back-yard about 9 years ago. Original owners had landscaped the front of the sand-mound (which faces the house). Planted various bushes and three pines. Two of the pines were Red Pines, not sure what the third is (has long needles).
Over the last few years, we planted some weigelas and lilacs in this same area, not knowing this was a big no-no.
The pines are planted about half-way down the side of the mound, on the front (end) of the mound. I have read that some trees can be planted on the toe of a sand-mound. But have also read that trees should be kept at least 20' away from a sand-mound. Should these trees be removed? Mound and trees have been in place for about 15 years.
Second question is re. the bushes. Are Weigelas and Lilacs known to have aggressive root systems? These are planted closer to the top of the mound, also at the front end. Would they be okay if we moved them further down on the slope? I really want to avoid a costly problem with the mound.