Hydrangeas should be planted in spring or fall when the sun and heat do not overpower the plant, and because hydrangeas lay dormant during these periods of time. Hydrangeas are transplanted in early spring or late fall when the plant is inactive. Hydrangeas thrive with sun in the morning and shade in the afternoon.
Hydrangeas are placed 3 to 10 feet apart depending on how much they spread out as they grow. Gardeners dig a hole as deep as the root ball and three times as wide to give roots plenty of space to move. Landscapers fill the hole halfway with soil, and then add compost if the soil has poor quality. Homeowners water the soil thoroughly to ensure the roots start growing into wet soil.
Mulch at the base of hydrangeas keeps weeds away and soil hydrated. Regular watering during the summer, when there is less than 1 inch of rainfall per week, is recommended to keep the soil moist. In areas with hot summers, experts provide shade for hydrangeas such as taller plants, walls and trellises.
Hydrangeas bloom in summer and fall, with showy clusters of flowers including white, pink, blue and red. Blooms and leaves fall off in colder months. Shrubs can grow up to 10 feet tall, with hydrangea vines reaching 50 feet around trees, houses and walls.