Hydrangea : Greenhouse Plants
C – cool, minimum of 7°C (45°F)
The hardy speciesmacrophylla from the Himalayas and China is often used as a pot plant for cool house displays in early summer. This can be done by rooting in spring and growing them on outside during the summer. They should be allowed just to feel the frost in the autumn which ripens them up before being brought into the cool house where a minimum temperature of 7°C (45°F) is maintained until January, when they are ideally warmed up a little to 13°C (55°F). Larger plants can be grown by bringing the one-year-old plants into flower for a second year. This is much the same procedure except they should be potted after flowering and cut back after they lose their leaves outside in the autumn. Leave either one or two pairs of good buds on the stem and grow them as before. Only the blue flowered varieties need an acid as alkaline conditions are apt to turn them pink. Try growing some of the attractive Lacecaps.