Barbara, you may be confusing MTB's with MDB's. MTB's are a median and can be treated like all other medians. MDB's are not medians but dwarfs. I find they need a cold period during the winter to thrive.
Just remember that the tallest and the smallest bearded irises are not medians.
The beautiful red iris of Lucy's is an MTB, a median, and I think it's name may be Billy the Brownie. Lucy?
Just another thought, MTB's are often used in florists arrangements because of the long sturdy stalks, the bloom size does not overwhelm other flowers and its cut blooms are long lasting. It was once referred to as the 'table top iris'' as they are ideal in bouquets. They remind me in the garden of butterflies as the blooms are well above the foliage and appear from a distance as if they are hovering over the plant.
