GROWING HYDRANGEAS SUCCESSFULLY

Covered with clouds of delicate blooms and infused with old fashioned charm and elegance, Hydrangeas are a sight to look forward to every summer.  They are widely known as Christmas Roses for this is the time of the year when they are most gorgeous and lush.

Varieties of Hydrangea

Gardeners are spoiled for choice with so many Hydrangea varieties and colours available and new ones introduced into the market every year.  The most regularly available and also very popular Hydrangeas at Lifestyle Home Garden are Hydrangea macrophylla (Big leaf Hydrangea).  They are available either as “Mopheads” ( Hortensia), featuring rounded, full heads of flowers, or “Lacetops” with flatter flowerheads made up of delicate florets, surrounded by bigger flowers, giving the bloom a lacy appearance.    Colours range from cool blues and purples, viby pinks, sultry rose and shimmering reds, to crisp, clean whites.  A single bush may sometimes even offer blooms of multiple colours and hues.

Lifestyle also stocks Hydrangea quercifolia (Oak-leaved Hydrangea), a very attractive plant, with similar needs and applications to their big-leaved cousin.  Their white, conical flowerheads last longer and well into autumn at which time the foliage turns a rich, bronze-purple colour.

Using Hydrangeas in the Garden

The application of Hydrangeas in the garden is very diverse: they can be planted en masse in beds for a breath-taking display from mid-spring to early summer.  Some of the new varieties, like ‘Endless Summer’ will even bloom right through summer on old and new wood. Single bushes can also be planted as focal points and smaller varieties can be planted along the fronts of beds and borders. They also do very well filling pots and tubs in semi-shaded spots and on cooler patios.

PLANTING AND CARING FOR YOUR HYDRANGEAS

• Hydrangeas prefer a position in dappled shade or where they will get morning sun, but not the harsh afternoon sun.  They will not thrive in a fully shaded position either.
• The best time to plant Hydrangeas is spring to early summer, or autumn.  Plant them in rich, moist, well-draining soil and add generous amounts of compost when planting.  When you’re planting more than one shrub, plant them at least 60cm apart to allow for enough space in maturity.  If you wish to transplant a Hydrangea bush, do so when it is dormant in late autumn or early winter.
• When planting in pots, use a good quality potting soil to which water retention granules have been added.  Ensure that the pots have adequate drainage.  Hydrangeas in pots will need to be watered and fed more frequently than those planted in the garden.

• Water well after planting and ensure that plants stay moist, but not waterlogged (especially during hot, dry periods) for the first two years until well established.  Once established, a deep watering once a week should suffice.  Apply a thick layer of mulch around the shrub and top it up regularly throughout the year.
• Christmas Roses are gross feeders.  Start with an application of 5:1:5 or 8:1:5 early in spring to promote healthy new foliage.  Six weeks later and every six weeks until growth slows down in autumn, apply either a 3:1:5 fertiliser or one of the specially formulated, water-soluble Hydrangea feeds available on the shelves at Lifestyle Home Garden.  Be aware that some of these fertilisers are specially balanced to maintain the specific colour of your Hydrangea, while others are simply a general food for all Hydrangeas.

PRUNING YOUR HYDRANGEAS

Pruning your Hydrangeas is important to ensure even, large blooms in midsummer.  If left unpruned for a long time flowers will be plentiful,  but too small and there will also be too much old, gnarled wood and not enough new, fresh growth.

Hydrangeas form their flower buds on the previous season’s growth (old wood).  Pruning  them back heavily increases the chance of removing some or all of these buds, resulting in few or no flowers being produced  in the season. Therefore, Hydrangeas should only get a light pruning, preferably in late winter in areas that experience heavy frosts, when they have lost their leaves and the shape of the bush and new buds are clearly visible. 

In warmer areas pruning can be done straight after flowering in January or February.  Cut old flowerheads back about 20cm, to just above a strong bud or cluster of buds.  Do the same with stems from the previous season that have become woody.  New growth should not be cut back at all.  Old or dead and gnarled woody stems must be sawed right back to the base of the plant, taking care not to damage any new basal growth.   Remove all straggly and weak growth as well.

PLAYING WITH HYDRANGEA COLOUR

The colour of Hydrangeas are affected by the pH levels of the soil. The acidity of the soil will determine how much aluminium is available to the plant, which, in turn, will determine the colour of the flower.

 Blue Hydrangeas need an acidic soil (pH below 6.5) and the pink varieties need an alkaline or limy soil (pH above 7,5), while the white varieties are unaffected by the soil’s pH.

The advantage of Hydrangea macrophylla is that the colour of the blooms can be changed over time by changing the soil pH and the amount of aluminium available to the plant.  This change will not be instantaneous and can take a few weeks or even months.  It is best to wait a year or two after planting to allow the plant to settle in, before playing around with the colour.

To change flowers from blue to pink, i.e. inhibit the amount of aluminium available, dust agricultural lime, according to the recommended dosage, onto the soil around the shrub once a month from spring onwards.   Always water in well.   Do not exceed the dosage as this can lead to yellowing of the leaves.

To change flowers from pink to blue, i.e. make more aluminium available, add acid compost or peat moss and aluminium sulfate to you soil in spring.   Apply the acid compost as a mulch around the shrub and water well.  Adhering to the recommended dosage on the packaging, either sprinkle the Aluminium sulphate around the plant or dissolve it in water and drench or spray the shrubs with the mixture once a month.

It is far easier to control the colour of your Hydrangeas and the pH levels of your soil if the shrubs  are planted in containers, rather than the garden bed.  It is also easier to change blue flowers to pink than vice versa.

HYDRANGEAS FOR THE VASE

Hydrangeas are perfect cutfowers for the Christmas table.  Choose mature, full blooms and trim the stems under water.  Immerse the flowers, heads and all, in cold water in a large container for a few hours before arranging.

The flowers can also be dried – that way you can have your Christmas Roses and still enjoy their beauty throughout the winter!

To find out more about Hydrangea varieties available at Lifestyle Home Garden or to shop online for Hydrangea plants, please click HERE