Q.Dahlia placement
I am considering planting dahlia tubers this coming spring and I wonder if my choice of placement is going to be okay. I have a stone wall that has large mature linden and maple trees on one side and the other side is cleared for the planting garden. The amount of light should not be a problem; however, I am concerned about the mat of fine roots. This root mat is just at the surface and is 5-10 cm thick. Under this, there is just soil. Will this root mat interfere with the growth of the dahlias? I am noticing that certain plants will grow without problem and others just don’t do well at all. Many thanks for any advice or recommendations!
Dahlias need full sunshine and warm, loamy, well draining soil.
If the soil is compacted with a net of roots it could be a drainage issue.
Ph should be between 6.5 and 7.0, slightly acidic.
You can add a small handful of Bone Meal in each planting hole and work in well before planting.
The soil could be amended with sand or peat moss or even steer manure.
https://www.gardeningknowhow.com/ornamental/bulbs/dahlia/tips-dahlia-planting.htm