Commercially available

• Blå Måndag
• Blue Monday
• Blue Moon
• Mainzer Fastnacht
• Mainzer Rad
• Navo-Rose
• Sissy
• TANnacht
• TANsi

224 favorite votes.  
Average rating: GOOD+.  

Bred by Mathias Tantau, Jr. (1912 - 2006) (Germany, before 1964).
Introduced in France by NIRP International in 1964 as 'Sissi'.
Introduced by Unknown (Australia) in 1965 as 'Blue Moon'.

Hybrid Tea.  

Lilac.  Strong, opinions vary fragrance.  up to 40 petals.  Average diameter 4".  Large, full (26-40 petals), classic hybrid tea, exhibition bloom form.  Blooms in flushes throughout the season.  Long, pointed buds.  

Medium, upright.  Glossy, dark green foliage.  

Height: 2' to 5' (60 to 150cm).  Width: 2' (60cm).

USDA zone 7b and warmer.  Can be used for cut flower, exhibition or garden.  Hardy.  prefers warmer sites.  Spring Pruning: Remove old canes and dead or diseased wood and cut back canes that cross. In warmer climates, cut back the remaining canes by about one-third. In colder areas, you'll probably find you'll have to prune a little more than that.  Requires spring freeze protection (see glossary - Spring freeze protection) .  Can be grown in the ground or in a container (container requires winter protection).  

'Blue Moon' is the registered name of the mauve Tantau Hybrid Tea which is sometimes improperly sold under the name of 'Blue Girl.'

Another rose known as BLUE GIRL is a Kordes rose registered under the name 'Cologne Carnival, according to Modern Roses 12.

According to HMF user The Old Rosarian, the Tantau rose 'Blue Moon' should have strong fragrance but is less "blue." The Kordes rose should have less fragrance, is blackspot susceptible but is a bluer shade of mauve.

Some question about parentage, see References.