I was explaining to someone recently that flowering cherry trees absolutely require well-drained soil to succeed. “Well, that’s not a problem,” they responded, “I’m planting on a slope, so water drains right past it.”

“Sloping soil is usually poorly drained,” I replied. “Your cherry will be dead in a year if you plant it on that eroded clay bank.”

It is important to distinguish between surface drainage and soil drainage. Water inevitably flows down hill. That is surface drainage. Soil drainage, though, is what happens to moisture when it soaks through the earth around a plant’s roots. Roots must have oxygen around them. Clay and water in the soil cut off oxygen. Going back to my recipe for bed preparation above, notice the sand I added. It, plus the organic soil conditioner, helps water soak past roots underground. Once the water is gone, oxygen flows into the soil and roots take a happy breath of life.