In a message dated 4/19/2010 10:04:32 AM Mountain Daylight Time, firstname.lastname@example.org writes:
The first few AB's I received as gifts to try, in 2001. I planted them on the sunny west side of my shed slightly under the eaves, on the south side of my property, in soil that was already sandy and gravelly; some TB's & SDB's were doing well there. A few miles to the east, most of the area is that type of sandy soil, but only a bit of my south side has that type of soil. The rest of my property is the "regular" Manitoba clay, so I mostly garden in raised beds or beds that have had the soil amended and raised slightly. My 3 main raised nursery beds are in full sun.
Most arilbredmedians have one median parent and one arilbred parent so their cultural requirements are more like that of their median ancestors than their TB or aril ancestors. This is the type I normally recommend for someone who has been successful with medians but has not tried arilbreds before -- because they can be grown alongside the medians.
Most arilbreds with one TB parent have an arilbred as the other parent so are predominantly TB and thus have cultural requirements more like their TB ancestors than their aril ones. This is the type I normally recommend for someone who has been successful with TBs but has not tried arilbreds before -- because they can be grown alongside the TBs.
I see examples of both types on your list, so choice of cultivars does not appear to be the problem.
One significant challenge faced by northern gardeners, however, is getting arilbred rhizomes in time for planting a full six weeks before the first killing frost. If they don't have the chance to get established during the fall growing season, they may not have the strength to make it through the winter or if they make it through one winter they are weakened so much that they then dwindle away.
I started growing arilbreds in the red clay of Oklahoma. Our landscape beds were slightly raised, bordered with a slight trench that separated them from the lawn, and served as a moat during a heavy rain. TBs and ABs were planted in the same beds. It sounds like your main beds are similarly raised.
I also experimented with planting iris next to the house, and learned the hard way that the west side of a structure was the worst place to plant arilbreds. It shortened the spring growing season by hastening summer dormancy, resulting in weaker clumps than those in the open beds, and led to the highest percentage of winter losses I ever experienced.