Why Do Roses Change Color?

Q: One of my roses doesn’t look like it has in the past.  The color and size of the flowers is different and the leaves aren’t the same.  What’s going on?  Is it the weird winter/spring we’ve had?

A: It could be weather stress from our strange Colorado winter and spring, but when a rose suddenly changes flower color, bloom size, and leaf shape all at once, there’s a very common explanation: your original rose may have died back below the graft, and the rootstock is taking over.

Most hybrid tea, floribunda, and many shrub roses are grafted. That means the beautiful rose you bought is attached to a tougher root system underneath. After a hard winter, freeze damage, drought stress, or temperature swings, the top grafted portion can die — then the rootstock sends up its own canes.

This year’s freeze-thaw cycle absolutely stressed roses. Repeated warm spells followed by hard freezes can damage the graft union, especially on less hardy roses.  Look near the base of the plant.  If the new canes are coming from below the swollen graft area, it’s likely rootstock.  Your original rose variety above the graft is gone and will not return.

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Read our Q & As with Keith Funk answering common Colorado gardening questions here. See his website: gardenwiseguy.com and hear him on the