Growing Clethra

I purchased several Summersweet over the Memorial Day weekend. Unfortunately, the 3 bushes are not doing very well. I planted them in heavy to part shade. I fertilized but they are not responding.

Summersweet (Clethra alnifolia) is a beauty that provides year round interest in the garden and is hardy in zones 4 to 9. They perform best in full sun or partial shade and moist even wet soils. I find them a bit difficult to establish in the clay soils. Adding organic matter to the planting bed, not just the planting hole, improves drainage while encouraging roots to grow far beyond the initial planting area.

Keep the soil moist and mulch to conserve moisture and reduce competition from weeds and grass.

Wait a year to fertilize. Research has shown better results and less root damage on new tree and shrub plantings when we fertilize a year after planting. If you can’t wait, consider using a low nitrogen slow release fertilizer.

Provide winter protection or plant new summersweet shrubs in a protected location free from winter winds. Though hardy to zone 4, a little extra winter care especially the first few years, will help increase success and speed establishment.  

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