Hello!
We encountered a bug that prevented Seedbloom from being rewarded through the completion of the weekly Blooming Dreamseeds quest.
We have now hotfixed the issue and it should reward 1 Seedbloom going forward.
Additionally, if you completed the quest before our hotfix went out, go to the Emerald Dream and then check your mail. The local postmaster should be sending out replacement Seedblooms.
Thank you.