read the link for more information, and maybe plant accordingly. though a bee will go where a bee will go, it isn't going to hurt, surely.http://en.wikipedia.org/wiki/Northern_nectar_sources_for_honey_bees
"The nectar source in a given area depends on the type of vegetation present and the length of their bloom period. What type of vegetation will grow in an area depends on soil texture, soil pH, soil drainage, daily maximum and minimum temperatures, precipitation, extreme minimum winter temperature, and growing degree days. The plants listed below are plants that grow in USDA Hardiness zone 5. A good predictor for when a plant will bloom and produce nectar is a calculation of the growing degree days. Hopkins' Bioclimatic Law states that in North America east of the Rockies, a 130 m (400-foot) increase in elevation, a 4° change in latitude north (444.48 km), or a 10° change in longitude east (two thirdth of a time zone) will cause any given biological event to occur four days later in the spring or four days earlier in the fall. In botany, the term phenology refers to the timing of flower emergence, sequence of bloom, fruiting, and leaf drop in autumn."