Roses all came back the same color, but why?

[mahsmaj]

My grandmother has about 5 large rose bushes. One white one, one pink one, one red one, and two yellow ones. During the spring of 2009 all of the rose bushes except the white one bloomed with a bright reddish-marroon colored roses. We have no idea why and wish someone knew why this happened but so far nobody knows... The white rosebush is the only one that blooms with the same white roses every year, the others all come back with the reddish-marroon colored roses. Sorry for the long post but i didnt really know how to word my thoughts. I hope you understood the post and thanks for looking!

 

[ranchhand]

Perhaps a change in soil chemistry? Water quality? fertilizers?

I know that hydrangeas in acid soil bloom blue, and if the soil is adjusted to more alkaline conditions they will bloom pink.

 

[Liana]

Fancy roses are typically sold as grafts onto hardy rootstock. If the grafts fail (hard winter, disease) or the bush is pruned back to below where the graft was, new growth will be from the rootstock.

 

[mahsmaj]

Ranchhand, That is the first thing that came to my mind but they have been there for at least 5 years then just came back a different color one spring... we never water them unless we dont have rain for more than two weeks but that rarely happens and we have never fertilized them. Its just got me stumped.

Liana, that makes perfect sense! we have pretty hard winters here sometimes and that also would explain them all coming back that way the same year!

 

[pbjmaker]

This happened to me too. It was a harsh winter that killed the grafts back to the original root stock which is general your basic hardy red rose.