| Hydrangea | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Scientific classification | ||||||||||||
| ||||||||||||
| Species | ||||||||||||
|
Hydrangea arborescens - Smooth or wild hydrangea Hydrangea cinerea - Small, ashy hydrangea Hydrangea macrophylla - French hydrangea Hydrangea paniculata - Panicled hydrangea Hydrangea quercifolia - Oakleaf hydrangea Hydrangea radiata - Silverleaf hydrangea | ||||||||||||
|
Sources: saxifrag ITS 24194 2003-06-29 |
Hydrangeas (scientific name: Hydrangea) are large soft-stemmed leafy deciduous shrubs which flower prolifically.
The flowers are carried in large showy bunches at the ends of the stems, but the actual 'flowers' are tiny - the display of colour is created by a ring of modified bracts around each flower.
The colour of a hydrangea's flowers is influenced by the acidity or alkalinity of the soil. Gardeners can control the display by adding lime or potash to alter the alkalinity level around the plant. Acid soils produce blue flowers , neutral soils produce very pale cream petals, and alkalinity creates pink or purple. Hydrangeas are one of very few plants that accumulate aluminum. Aluminum is released from acidic soils, and forms complexes in the hydrangea flower giving them their blue color.
Hydrangeas are deciduous. Some varieties should be pruned on an annual basis when the new leaf buds begin to appear. If not pruned regularly, the bush will become very 'leggy', growing upwards until the weight of the stems is greater than their strength, at which point the stems will sag down to the ground and possibly break.
Other varieties only flower on 'old wood.' Thus new wood resulting from prunning will not produce blooms the following season.