The bloom may have dried out or may have been spent. Those from tiny plants do not last as long as others from 3 gallon pots plants. I surmise they do not yet have an extensive root system that can supply with the amt of water needed so they dry out earlier. If they turn from blue to brown directly with little color shifts to greens and pinks then it is drying out as normally the blooms should go from blue to shades of greens and/or shades or pinks.

The shrub looks great now but try to detect dryness by inserting a moisture meter or by inserting a finger into the soil to a depth of 2". These methods can help avoid over-watering too, something that crossed my mind when I saw water not draining in Picture #2. The potting soil type should be well draining and acidic; soil from the garden usually does not drain well in pots. Also, make sure the pot has unobstructed holes at the bottom. Otherwise, it looks good.

As for whether it will bloom again this season, it may if it is a rebloomer hydrangea but reblooming happens later, around July or August in your area. If this is not a rebloomer then it will bloom again in 2019.

Luis

Great information Luis! Thank you so much! I had no idea about the moisture method, will try it out! This container has holes for drainage, but I will make sure they're not obstructed. I just went outside and took a photo of it today to see how it's doing, so far looks good.. I hope it will bloom this year, but if not looking forward to it next year.