Name: hydrangea (Hydrangea macrophylla cvs).
Plant type: small to large deciduous shrub.
Height: variable, range from 0.5–2m.
Foliage: large (10–20cm long × 10cm wide), oval-shaped but variable, serrated edges, deep to bright green.
Climate: all but arid zones.
Soil: moist, rich, well-drained soil.
Position: part shade or dappled light under trees.
Flowering: November to February. Shades of pinks, blues and white.
Feeding: gross feeder. Requires annual fertilising and mulching with compost or composted manures.
Watering: requires reliable moisture, especially while actively growing and flowering.
The hydrangea is dormant across winter and bursts back into life come spring. Most plants will naturally form a dome-shaped shrub, meaning flowers are borne clear of the foliage. A plant that’s performing well can be almost entirely covered in blooms.
The hydrangea is notorious for changing flower colours. This all relates to soil pH. The simple rule is this: acid for blue, alkaline for pink, and white will always be white. Colour is genetically limited, so a blue will only be able to get to a certain intensity of blue, for example. You may be happy whatever the flower colour, but changing it is reasonably simple:
Required pH levels for the various colours are as follows:
Hydrangea is a bold shrub that adds real “wow” to shady areas. The foliage provides an excellent filler and backdrop for other smaller plants. The hydrangea is unsurpassed for its flowering display in shady spots, and the flowers are excellent for cutting and displaying in a vase. Hydrangea is a great problem solver, as it’s happy in shade and moist spots.
Your hydrangea will generally require part shade or dappled light. In some circumstances, some forms will tolerate full shade or even full sun. Soil must be of good quality with good drainage.
Hydrangea is classed as a “gross feeder”, which simply means it is very hungry, so add extra organic matter if required.
Protect your plant from strong winds, as their stems are brittle, and ensure it has reliable moisture, especially during peak growing times.
Watering appropriately is critical for best performance. During warm weather and peak growth times, make sure soil remains moist, or both flowering and foliage will suffer. Consider installing a suitable computerised drip irrigation system at planting time to make correct and efficient watering a set-and-forget task.
Hydrangeas like rich soil with plenty of organic matter and nutrients. This is easy to achieve. Mulch in spring with compost or manure, then add organic mulch over the top. Lucerne or pea straw are excellent, as they break down quickly, adding extra organic matter to the soil. Pruning hydrangeas
Hydrangeas flower on the previous year’s new growth, so pruning is essential for best flowering. Follow these tips for best results:
Scale insects may occasionally attack hydrangeas. These are easily treated with a suitable horticultural or pest oil. Powdery mildew may appear on leaves as a grey/white powdery dusting. Remove infected leaves, seal in a plastic bag and dispose of them. You can also spray with a suitable safe fungicide such as Eco-Fungicide.
There are a number of easy techniques for growing a hydrangea from cuttings, including:
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