We have suffered in the past with gritty fruit from touching the ground. Fixed it this year, using cheap plastic forks. Push the handle end into the soil and drape the fruit stem over the fork tines, keeping it high enough not to touch the ground. Works a treat.

This might be due to improper cultural practices or unfavorable environmental conditions. Cultural and environmental factors relate to moisture, light intensity, growing medium, pot size, temperature, humidity, fertilization, air circulation, and other factors. The best method of combating root problems is to prevent them. Avoid over-watering. The growing medium should be pasteurized if possible, well aerated, and easily drained. (Water should drain out the bottom of the pot after watering.) Know the needs of each of your houseplants. The amount of moisture required is dependent upon the type plant, the size of the pot, the type of growing medium, and other environmental factors. Also, avoid over-fertilization. If a root rot problem develops, try reducing the frequency of watering.

Thin the plants when you renovate your bed after the last harvest, improving airflow will really help. Next year make sure you have straw or some type of mulch between the plants to keep the berries off of the soil. When your strawberries start to form fruit next season, make sure to remove any of the lower leaves that die from being shaded out, they will rot and cause problems if your fruit is resting on them. The mystery animal taking one bite is probably birds, put some netting over the plants to protect them.

If you are going to amend, do not amend only the planting hole, especially in clay soil. You need to amend as large an area as possible, preferably the whole bed. That is because an amended hole in clay soil usually creates a “bathtub” where water from irrigation or rain fills the amended hole and then doesn’t drain away, causing the roots to rot. It is better to add amendments such as compost on top of clay soil if you cannot amend a really wide area. You can also plant a bit high and place the amendments mixed with native soil to create a bit of a mound around the upper part of the rootball that is higher than the soillevel. PH of 6.5 will make the plant happy. As others have said, keep your hydrangeas well mulched (though not directly against the stems) and the soil moist, not soggy for the first 1-3 years. After that, my panicled hydrangeas have needed no supplemental water, even in full sun and drought conditions. YMMV depending on your native soil and precipitation, but unlike your Bloomstruck, panicled hydrangeas like VS are happier on the drier side than wetter and don’t need a lot of extra moisture. Use the look of the foliage to decide if it is too dry once they have been there a few years. As a side note, your Bloomstruck may shift to a more blue tone to the blossoms once the roots have reached into the native soil beyond the potting soil since your pH is slightly on the acid side, as long as the soil has some aluminum. Also it may need some winter protection to get spring blooms in zone 5 since the shrub as a whole is hardier than the flower buds or even the branches. My bigleafed hydrangeas like Bloomstruck often die back to the snow line so I don’t get flowers until late summer or fall on the new growth.