This cultivar is listed as diploid in the paper 'UNDERSTANDING AND MANIPULATING POLYPLOIDY IN GARDEN ROSES'

Maryland 7a
I bought this last year from Burlington rose as a band. It is small, as it should be. It is in a pot. Right now, in june, it has about 8 flowers and more buds on it. The flowers are really pretty. The color is a peachy pink. The leaves look good. Edit- a few weeks later and the leaves have really succumbed to blackspot pressure. It is quite defoliated now unfortunately.
I was planning on buying more of this because I liked the flowers so much, but I will see how this recovers from our hot/humid spell.
update- did not survive it's second winter.