Here in Texas, Big Leaf Hydrangea cultivars require in the summer only morning sun exposure until 11am or earlier: no 12pm summer sun, no afternoon summer sun and no evening summer sun. The soil has to be kept acidic and always evenly moist at a depth of 2-3" in pots. Keep the pot away from windy spots. Water only the soil and never the leaves to minimize leaf spots due to fungal spores germinating. Aim for evenly moist soil in the summer so test it daily in the morning. Do not water if already wet. Discard/reuse any water in the saucer. If the soil at the bottom is often wet, consider drilling more water drainage holes. Feel free to use any general purpose, slow release fertilizer with a NPK ratio of 10-10-10 or a fertilizer like Holly-tone. You should get one flush of spring 2023 blooms from dormant flower buds that develop inside the ends of the stems in July 2022. You should get a second flush of blooms as soon as the new 2023 spring stems get tall enough to bloom in the summer of 2023. But that is it. The plant typically produces only one bloom per stem ending per year. A fungicide like Bonide Liquid Copper Fungicide can help control leaf spots provided you never water leaves and use clean sanitation practices. Discard the worst leaves by clipping the string that attaches each leaf to the stem.
