Larry Smith and the Riverside Gardens team talk all things pots, plants and pruning in their weekly gardening column.
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A few weeks back we had a customer chasing after a some Acmena Fire Screen to complete a hedge, being a variety we don’t normally carry, we offered to order them in for him.
It was during this discussion that it came to light that he had been misinformed by a prominent plant retailer that he could trim these down to form a 30 to 40cm border hedge around his rose garden.
This variety of lilly pilly usually grows to 3 to 4m high and 2m wide.
The concept of his design was good, but the plant selection for the low hedge was never going to work.
The choice of any hedging plant, no matter what height you are trimming it off to, can be a bit tricky, as not all plants lend themselves to being treated this way when growing.
Some plants will continue to push out long spindly growth when pruned, while others can be reluctant to push out new growth at all when cut back hard and others just have the wrong structural habit and shape to do the job.
In this case, however, it was not just that the plants were going to grow way too large for the proposed use but, they were also probably the wrong style and had different growing requirements compared to the surrounding plants.
For a low border hedge in this situation, a more practical choice would be euonymus Tom Thumb.
It is well suited to this style of planting and performs better than the similar option of Buxus sempervirens the English Box in our region.
Tom Thumb copes well with our weather extremes, establishes quickly, recovers readily from damage and, with proper care, maintains a consistent dark green colour.
It also lacks the strong smell that English box can produce when flowering.
It can be clipped tightly for a traditional formal hedge or left to form a softer, flowing border.
For a more traditional low box hedge, my choice would be Buxus Microphylla the Korean Box.
Its fine, glossy foliage is softer than that of English box, and its naturally dense, compact habit allows it to be kept low and narrow with less maintenance.
Korean boxes grow quicker, has that softer appearance and produces a far less pungent smell when flowering than English box.
Escallonia ‘Pink Pixie’ and escallonia ‘Newport Dwarf’ are also suitable for a low clipped hedge, with the added benefit of small, attractive pink flowers appearing intermittently throughout the year.
Both have fine, glossy leaves on attractive red stems and grow quickly.
If left untrimmed, they form low, rounded shrubs to about 50cm high and wide but can be trimmed to form a tight hedge 30 to 40cm high.
They perform best in a full sun position with good ventilation and drainage; in damp cool soil they can be susceptible to escallonia leaf spot which will disfigure the foliage and require treatment.
Gardenia radicans could be another option well worth considering, although they would look best as a soft flowing low border rather than a tight clipped low hedge.
Gardenia radicans will grow happily in a full sun position with good drainage.
Gardenia radicans have a prostrate spreading habit if left unclipped. But with the occasional light prune they will form an informal dense border with glossy green foliage topped with small semi double white fragrant flowers from late spring and throughout summer.
Another gardenia that could work well is Gardenia Buttons with its neat upright rounded habit.
It could be used as either an informal border or a formal tightly clipped hedge.
If not trimmed, it would reach 60 to 90cm high, but it could be easily hedged as low as 40 to 50cm.
Gardenia Buttons gets its name from its abundant semi double highly fragrant white flowers that have a button-like appearance in the centre.
Loropetalum Little China Ruby, a dwarf form of the purple leafed Chinese Fringe Flower, can be clipped to form an exceptional low border to about 50cm high.
It has deep plum coloured foliage all-year-round, and in late winter, spring, and autumn it can flush over with vibrant, bright magenta-pink tassel flowers.
Left untrimmed, it would form a low shrub 80 to 100cm high.
If you are looking at using a lilly pilly as a low border hedge there are a few very good options available.
Acmena Allyns Magic is a naturally growing dwarf form of lilly pilly that grows to around 50 to 70cm high, so it can easily be hedged down to 40cm high.
The new growth comes out a shiny bronze to pink colour before fading to a glossy green leaf and they are resistant to psyllid damage which can affect a lot of lilly pillies.
Acmena Little Ruby is a similar lilly pilly which has much of the same characteristics, but the new growth is a bright red to deep burgundy before turning glossy green.
These are only a few examples of the different types and styles of plants that could be used to form a low border along a garden edge.
Each has its own appeal, growing requirements and suitable styles they could work in with.
So, considering the time and effort that you are going to invest in establishing a garden border it pays to get it right the first time.
If you are unsure, be sure to ask the questions.
Furthermore, be sure you are asking the right people the questions.