Asked August 08, 2016, 11:42 AM EDT
Knox County Tennessee
As long as you have been watering (about 1.5" every 7-10 days or so), it shouldn't be that it's too dry. Newly transplanted bushes go through transplant shock which can be an 18 month period of time. It's your responsibility during that time to water -- deeply and infrequently.
The only way to know is to dig down and see if soil is moist around the roots.
The other side of that coin is too much water which will manifest itself as wilting. Again, the only way to know is to dig down and see.
However, I have seen forsythia go down due to phytophthora root rot. The plants wilt due to non-functioning roots. If one of your plants is going down, dig it up before it's completely dead and take it (plant with roots and all) to your local Extension office for a diagnosis. Do not take them a dead plant.
Hope this helps.