Knolls are great for growing fruit primarily because they are less prone to frost than low pockets. Cold air is dense and slides off knolls and slopes while puddling up in low pockets.
The downside of knolls is wind. Even species and varieties that are generally considered hardy can take a pounding during winter winds. Another issue is that graft unions can break. A third issue is that a strong wind can discourage pollinators even if the day is warm and sunny.
The answer, of course is to plant a windbreak. It does not need to be very tall as my trees top out at about 12' in height.
|If you are counting on your windbreak to jump-start your bee population then be sure to plant the pollen/nectar plants on the lee-ward side of the windbreak.|
I really don't have a lot of room to shoe-horn in a multi-row windbreak and I want to get extra utility out of the windbreak. For instance, it would be grand if there were species that bloomed through-out April to boot up the native pollinator populations before the apples bloomed in early May. I also value plants that have persistent fruit or produce hard mast.
|Photo taken July 28. Apple cultivar is Novaspy. Lesions are Cedar-Apple rust.|
|And here is Typhoid Mary (a Red Cedar), just across the fence on the neighbor's property...immediately upwind of my orchard.|
You also won't see sumac. I like sumac. It grows well and produces fruit that sustains birds on their spring, northbound migration. The problem with sumac is that it is too coarse. The stems are large and sparse. You can look right through a sumac thicket. It will not provide much resistance to the wind.