I have an area where I want to plant an hydrangea. It stays moist due to a central air unit that drains. I know it can't be soggy soil but how do I tell if the soil is soggy vs moist. In my opinion it's moist because the soil is not squishy. What's yall's opinion?

Perhaps dig a hole approximately as deep as you plan to plant your hydrangea and see whether it collects water.

If you keep the area "mulched" with organic matter, renewed as needed, drainage won't be a problem and the consistent moisture should grow an amazing Hydrangea. But will plants block the airflow to/from the unit, &/or block access for maintenance? Is it a heat pump that blows hot air when the A/C is running? If so, Hydrangea might not like that part of the arrangement. But also if so, the water drainage from it could be directed toward a Hydrangea a little farther away, with rain-gutter type arrangement. I would just avoid doing it with concrete because that would raise the PH and could do it enough to turn a blue Hydrangea pink. Keeping the area where it is growing mulched will help keep the PH lower, as well as the moisture/drainage moderation.

Thanks. No, it won't affect maintenance. There's a slope and the the area where it stays moist is actually about 20' long. That's why I thought it would be an ideal location for the hydrangea.