The following is a quote from Sparck's thread: Double Gardening Overview
"Also, while it’s called Double Gardening, you can only get 1 seed in return. Crowns-only plants guarantee this seed return, but normal plants that are not Crowns-purchased may or may not drop a seed. It all depends on your gardening green thumb and some luck!"
END QUOTE
The problem is that this quote makes it seem as though harvesting a Jewel Blossom would be a bad idea. These five plants are supposed to always give back their seed and provide a chance of receiving one of the five Jewel Blossom seeds as a rare second seed from the harvest.
The fact that I have never received a second Jewel Blossom seed from a single harvested Jewel plant after the change in Double Harvest coding, coupled with the fact the second seed is a rare harvest and the fact that KingsIsle had to write code to prevent elder harvests from returning a second seed, leads me to believe that you cannot get the rare second Jewel Blossom seed during double gardening rewards.
