Best choice for back row of north facing foundation bed
Hello, I have amended and extended the foundation beds of the home we recently purchased that previously grew only hostas and tulips. It was heavy with clay and maple roots. I’ve tilled, incorporated shredded pine bark, peat moss, coarse perlite & sand, elemental sulfur and gypsum. I currently have some low growing phlox and candytuft in the front row, ~3’ ft hydrangeas in the middle and an assortment of Ericaceous evergreens in the back. I’d like to have a uniform back row, though, and and wondering which of my current cultivars would do best in this north facing 5b bed. I planted the back row in late summer/early fall, so I have yet to see for myself how they bloom in the spring and I’m looking for recommendations. This row would receive the least amount of sun obviously, direct sunlight in the morning only and some radiant light the rest of the day. My current plantings are Pieris Japonica ‘temple bells’, rhododendron ‘boule de neige’, and kalmia latifolia ‘pristine.’ I also have a couple ‘gomer’s waterers’ rhodos I could bring into the the mix - they are currently overwintering in my garage. Of these, which will bloom best with the least amount of light? Which should I consider moving up or transplanting to my side garden for more sunlight? Thank you!
This is a difficult question to answer, particularly without the ability to see the bed. It is more of a judgement call than anything, your judgement. The plants that you like. Evergreens of various types and sizes would anchor the back row effectively while aesthetically pleasing. Rhodos will flower nicely in deep shade but can become quite tall if happy. The most important thing for rhodos that I'm not reading is your soil pH. They need acidic soils to flourish. They also are not deep rooted plants and survive best when when undisturbed, with some protection from drying winter winds. For all of your soil improvements you still do not know pH and nutrient levels. For that you need a soil test, the only way to accurately determine soil makeup, pH, nutrient levels, etc. https://homesoiltest.msu.edu/
A soil test is always recommended when beginning new gardens, as well as every three years or so going forward because soils and nutrient levels can change. There is simply no other way to know your soils fertility, however nice it may look and feel to you.
As for plant placement, the tried and true method of tallest plants to the rear is usually the most effective and pleasing aesthetically, as well as functional so that nothing is starved for sunlight. Pay attention also to mature plant size, as estimated on plant tags. The right plant for the right place is the mission.