The proper way to grow rhododendrons

Three years ago, I planted a rhododendron which I have covered carefully each winter. I?ve improved the soil annually with triple mix and used aluminum sulfate according to the directions. Buds set each year, but rot in the spring instead of opening. The bed is surrounded by lawn on the north side of the house and gets full sun. Would it help if I dug up the plant and raised the bed?

?Gail Browne, Uxbridge, ON

That situation is terrible for rhodos. These are forest-edge plants and like a dappled shade, so it is being overexposed. Good drainage is also important; I suggest you take it out and plant it away from the grass on a slight rise or mound composed of humusy soil mixed with small bark chips. Rhodo roots are fine and silky and don?t compete well with something as dense as grass. Add a layer of compost every year and mulch with pine needles or shredded oak leaves if you can get them to keep the soil acidic. Rhodos take about four years to acclimatize so persistence will pay off.

?Marjorie Harris, Editor at Large