A couple years ago I purchased a white coneflower and for the first 2 yrs it was white, now it's pink & white.?

There are two types of Echinacea that are considered to be Heirloom varieties; the common Purple Coneflower and White Swan (which is white with an orange center). These would probably be genetically stable. But other varieties such as White Lustre (white with a green center), Jade (white with green center) are newer hybrids and may revert to original colour over time. Their offspring would certainly be different from the parent if the seeds are viable.

Soil Ph sometimes affects flower colour in small amounts. Echinacea's natural habitat is a little on the alkaline side.

It' it's not a stable cross, that is all flowers will be pink, yes this might happen. Also differences in growing conditions.........maybe with warmer weather the flowers appear more white....also goes back to the stable cross.

The other thought is if this has occurred in the years following planting, you may be getting plants from seeds that fell to the ground and being hybrids, they are reverting back to original parents.

Deadheading not only keeps the plants from wasting energy producing seed when you don't want it, it also weakens the plants by energy loss. Might this be a problem that affects color? Hmmmmm?

The white ones may have been created by combining two or more other varieties and may be reverting back to one of the originals. Even if you deadhead it may continue to do this.

could it be the lime in the soil, like w/ hydrangeas? http://www.hydrangeashydrangeas.com/colorchange.ht...