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Pruning Made Easy: how & when to prune absolutely everything

Topiary & Bonsai section written by Carol Bucknell | NZ Gardener Special Edition, April 2016

The ancient arts of topiary and bonsai take a little time and skill to master but the end result gives a definite garden wow factor. 

Who says you need loads of space to make a good garden?

For impatient topiarists wanting to create a wedding cake, buying a triple pompom topiary will give you a headstart of 5 years or more, suggests Rachael. "Then just flatten the balls, taking the curve off by levelling the top and bottom of each ball"

Q & A: I'd like to try my hand at topiary. Where do I start?


It's best to start your first topiary with a simple shape such as a cone or a ball. Plant choice is the key: the ideal species for topiary are those with dense growth and tiny leaves. Experts recommend one of the many Box cultivars for beginners as it is one of the most forgiving evergreen shrubs, being long-lived and hard to kill. You could, however, try corokia or pittosporum if you prefer native shrubs.


When selecting a suitable plant, make sure it is healthy, has a balanced branch structure and suits the shape you want. If you're after a standard or a lollipop shape, for example, you'll need a strong central trunk; whereas for a cone you'll need a specimen that has an upright growth habit.


Topiary expert Rachael Matthews of HEDGE Garden Design & Nursery in Wellington suggests using the shappe of your pot as a cutting guide - a round pot for a ball and a square pot for the base of a pyramid. Having the right tools is also essential: long handled shears for the first rought shape, plus shorter topiary shears for the fine finishing work.


Your mantra should be: the more you trim, the denser the plant will grow. The opposite happens if you leave it too long between cuts - plants get out of shape, resulting in gaps in the foliage. "It's better to trim a little and often," Rachael says. "This way, all the growth is going in the right direction, rather than cutting off a large amount of unwanted growth once a year, which is a waste."



Creating Topiary Shapes


Once you've learned how to design the simpler topiary forms, let your creativity soar with whimisical flights of fancy.



A Wedding Cake


1. Use the same method as a triple pompom, says Rachael Matthews. Choose a plant that you'd use for a standard topiary, one with a vertical form.Remember the bigger the leaves, the larger you need to make the topiary, otherwise you won't get a crisp definition.


2. Allow your plants to grow a single tall leader to full height, then cut the leader to force the side growth. These lateral branches will form your tiers.


3. Work out your finished proprtions and tiers. if you are not happy trimming by eye to guage whether your proportions are right, draw the topiary to scale and work out the thickness of each tier and gap. Then use a tape measure against the stem to work out which sections of the stem to clear.


4.You can also mark the stem dimensions with a permanent marker on bamboo cane and attach it to the stem. This means that you will always have your dimensions handyover the years and the cane will help keep the leader straight until it hardens off.


5. Cut back foliage to create the gaps between the tiers. Rachael recommends a 5-10cm gap or "negative space" on the stem between layers.


6. Work slowly and make sure you have the right perspective - step back to assess your progress often. 


7. Make the bottom layer slightly thicker and wider than the layer above to create a staggered tiered structure. This looks better and also allows light to the lower layers, which encourages better growth.


8. Layers will be short and sparse to start with but will gradually spread horizontally and will ultimately grow into a flat disk shape.

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