I loved the blooms on my Margo Koster but she wasn't very vigorous and didn't winter for me.

I also have a beautiful red one, Zenaitta, that is a real bloom machine! Even more than my Verdun which has remained rather small for me. Zenaitta is about 4 X 4 and in constant bloom while Verdun blooms in rather slow repeating flushes.

My parents' house had a Margo Koster by the back door. She was there when we moved in and lived another 30 years. When I moved in here, I planned oine by my back door. She's doing fine.

Faves:

Baby Faurax

Excellenz von Schubert

Leonie Lamesch

Lullaby

I have several Margo Kosters, all rooted from an ancient one (at least 70-80 yrs old) that is growing under a giant barberry bush. I dug up the original and moved it twice, but it came right back in the same place!

Mine sport continuously (by which I mean at least once a year) to a very pretty very dark pink - the Koster family of roses is evidently famous for that (which is why it is a "family").

Another one I really like is 'Lauren' - hybridized by Kim. It is the same color as 'Veilchenblau' (perhaps a little redder). I planted it a year ago, and so far it is about 2 1/2 feet high and has been blooming continuously since April. HMF says it is hardy to zone 2.

Polyanthas are wonderful - plant several!

Jackie

Consider some of these:

Perle d'Or
Lady Ann Kidwell
Blue Mist
Opal Brunner
Leonie Lamesh
Marie Pavie

(I did not vet them for zone hardiness....sorry)