The hydrangea macrophylla or florist's hydrangea makes a popular gift, with its bright blue or bright pink blooms. According to Hydrangeas Hydrangeas, these plants have been fertilized and bred to put on a one-time display of elegant flowers. With care, gardeners can coax these hydrangeas into becoming long-term house plants, or they can enjoy the plants indoors during the autumn and winter months and transplant the hydrangea macrophylla into the garden when spring arrives.
Place your hydrangea macrophylla plant in a south-facing window or a similar location where it can receive bright light but not direct sun. Keep it in a cool room. If you want, move your hydrangea outdoors during summer months and bring it back indoors during the late autumn and winter.
Water your hydrangea macrophylla regularly whenever the soil becomes dry. To check the soil's moisture content, stick your finger down in the soil a couple of inches. If that soil feels wet, hold off on watering; if it feels dry, water. Each time you water, do so until the water flows out the drainage holes at the bottom of your pot.
Cut back stems that have flowered to have their height using scissors or anvil pruners. This will promote branching and allow the hydrangea to continue flowering.
Decrease your watering in the late autumn and early winter, as this is the hydrangea's dormant season. Allow the hydrangea to remain dry for several days in between watering.
During the mid-winter, move the hydrangea into a brightly lit room and increase the watering to standard level you provide in Step 2.