Bougainvillea and Lime Sulfur Application

I treated the dead wood on this bougainvillea, it’s still kind of yellow and hasn’t turned white yet? I thought this was suppose to happen?

I have not had that experience, nor have i used it on Bouganvillia. I would suspect one of the following possibilities.
How well shaken or mixed the product was before application. Older product with considerable evaporation may be more concentrated and darker yellow.
Dilution of the product. ( i have been in the practice of diluting to half strength and applying lighter coats at intervals after allowing time for thoroug drying between coats.
Humidity very high is another possibility!
The whitening is brighter as the product dries, how long after application were the pictures taken?
If the whitening does not occur shortly , i would just brush the surface with water to remove the color. Try to prevent the product from draining into the soil and roots if possible.

Picture was taken less than 12 hours after application. I did use full strength.

If you think it has been applied quite thickly then you might consider a rinse with water and light brushing, try to keep the lime sulphur off live material and from dripping into the soil. Then let it dry thoroughly. It should turn paler white as time goes by. If you wish a starker white look then repeated lighter coats over a period of time is better than a heavy coat. Good luck with the process.

I brushed and rinsed the line sulphur off of the tree. I watered the soil throughly to dilute and remove any lime sulphur that may have leached into the soil.