Although they are usually grown as shrubs, hydrangeas can be successfully grown in pots. Potted hydrangeas require a modest amount of care and attention to produce healthy blossom clusters. You need a pot, soil, a root ball, fertilizer, water and shears.
Fill the pot with soil
Use a rich, damp soil enriched with compost. Use well-draining soil to prevent overhydration and rot.
Dig a hole
The hole should be two to three times as wide as the root ball and equally as deep.
Plant the root ball
Place the root ball into the hole. Add enough soil to cover the root ball completely. Water the root ball, then fill the rest of the hole with soil when the water is done draining.
Provide appropriate sunlight and shade
Some varieties do well in partial shade, but most thrive with full sun in the morning and shade throughout the afternoon.
Water when the soil is dry to the touch. If the plant is wilting, water it immediately. Water the hydrangeas until water leaks out of the drainage holes.
Fertilize the plant
SFGate recommends using an all-purpose, controlled-release fertilizer once per year in the spring.
Trim and deadhead
Use your shears to shape the hydrangeas in the midsummer when blooming has ceased. Remove dead blooms to encourage continued blooming.