Advanced thinking

Advanced thinking


home gardening

If you want shade, privacy or a well-established look in a hurry, use advanced trees

By Diane Norris

The beauty and value of trees cannot be understated, especially in the home garden where trees provide shade, a feeling of tranquillity, a habitat for native wildlife and can even be planted as living memorials for future generations to appreciate. Trees improve air quality and are climate-controllers, moderating the effects of sun, wind or rain. Apart from these benefits, trees also are valued for their role in the design of a garden. They can be used to provide privacy, emphasise views, function as living screens or act as sculptural features that enhance the look of a garden and provide unique focal points.

In this article, we take a look at the use of advanced trees (sometimes referred to as mature trees). This doesn’t mean tube stock or the usual nursery stock in eight- to 10in pots, nor does it mean “old” trees. It means substantial trees: big, tall, ready-to-plant trees especially grown by specialist nurseries. Some of these trees are in 150-litre containers and have been progressively “potted-on” over a period of several years to attain their stature.

Why use advanced trees?
So when is a mature tree the better option? I asked Craig Rich, Operations Manager from Alpine Nurseries in Dural, New South Wales, about choosing, planting and caring for mature tree stock. Craig advised there are several reasons why selecting a mature tree could be the better option. Councils and developers have been using mature trees for years, as the likelihood of them getting vandalised is significantly lower and their rate of survival with minimal maintenance is higher. This can be applied to the home garden, especially in built-up and urban areas. Additionally, they provide an established look to a home garden that instantly adds value and creates a more positive impression.

Craig says that he is seeing an increase in the use of advanced trees in home gardens. This, he says, is because it is now common for large houses to be built on smaller blocks of land, so people are looking for ways to provide shade and privacy as quickly as possible. He adds: “Generally, today’s gardeners are impatient and don’t want to wait for a tree to grow, so would prefer to pay more to get a mature specimen and have an instant garden.”

Things to look out for
The first thing to look for when choosing an advanced tree is that it has a straight, clear trunk with a good calliper (good trunk width) and stem taper. Stem taper is the gradual and uniform narrowing of the trunk towards its top tip. The branches should be evenly spaced and well balanced, which means they sprout from the trunk at even intervals and are about the same comparable length as each other as you look up the stem. The lower branches should be longer with a nice, gradual shortening of size as you move your eye up to the top of the tree.

The tree should be firmly rooted into the potting mix. If the tree appears to be loose or wobbly in the pot or bag, do not purchase it — it should be firm. To test this, just gently hold the trunk of the tree and move it a little from side to side. You will quickly notice if the roots are well bedded.

It’s a good idea to purchase, as well as plant-out, mature tree stock during mild times of the year. Autumn and spring are ideal when the temperature variation is less. Of course, you can plant trees at any time of the year, but in extreme conditions extra attention and proper tendering are vital.

Which trees are best?
Nowadays, many species of specimen trees are readily available in very large sizes indeed. In Sydney, a memorable moving, by The Specimen Tree Nursery of Peats Ridge, saw the transport of 90 fig trees, in six barge trips, make their way to Homebush Bay. The largest of these was a Moreton Bay Fig (Ficus macrophylla), weighing some 280 tonnes. Although not quite for the average home garden, it shows what can be achieved.

Some trees need to be craned into their planting position, while others can be manoeuvred by hand. For the domestic market you will find an excellent range. There are the deciduous favourites such as Liquidambar styraciflua, Platanus acerifolia (Plane Tree) or Ulmus parvifolia (Chinese Elm). Natives haven’t been excluded and you will find mature Banksias, Blueberry Ash (Elaeocarpus reticulatus), Eucalyptus species and Lilly Pilly (Syzygium luehmannii) to name but a few.

For a special effect and dramatic landscape statement, tall palm trees such as Date Palms (Phoenix canariensis), Livistona Palms (Livistona australis) or the Kentia Palm (Howea forsteriana) are available. However, often these palms need special attention during transport and planting and it maybe wise to leave it in the capable hands of a landscape contractor, qualified horticulturalist or arborist.

Where to purchase trees
Some plant nurseries carry trees in larger pot or bag sizes, from 40cm pots, 45-litre containers right up to 100-litre bags. But if you want a truly huge specimen you will need to seek out a specialist advanced-tree nursery. You may like to speak to a licensed landscape contractor or qualified horticulturalist for sound advice.

Good specialist advanced tree nurseries take pride in every aspect of producing advanced specimen trees and they are well placed to provide advice on tree selection, planting and care. Some formulate their special potting mix blend to assure optimum growing medium for their charges. In-house propagation also maintains the quality of tree.

Nurseries specialising in advanced trees are located in every state of Australia and can be found via the internet or by asking at your local nursery or good garden centre. Many supply and transport Australia-wide but, of course, this can be a very expensive exercise.

Planting and care of trees
The primary goal when planting an advanced tree is to inflict the minimum amount of stress on the plant. All trees must be thoroughly watered while still in their pot, container or bag on the day of planting.

Dig a hole — not too much deeper than the depth of the tree’s root-ball, and at least two, if not three, times wider than those roots. It could be a good idea to test the soil, with a pH testing kit, to make sure the soil is the optimum growing medium for the tree. Improve the excavated soil with composts, lime or slowrelease fertiliser, depending on the pH results, and mix in well.

Trees must be planted immediately after they have been removed from their container. You may need several pairs of hands as some of the pots are big. If enormous, landscapers will use machinery to lift and lower the mature tree into place.

Once in the hole, make sure the top of the root-ball is level with the surrounding ground level. Backfill the hole with the newly improved soil dug from the hole and firm into place as you gradually backfill to squash out any air pockets.

Next, form a circular “dish”, or well, of soil around the top of the root-ball. Make sure the radius is large enough to hold good amounts of water as it is purposely created to carry water directly down into the roots.

Finally, staking may not be necessary but you should do so if the trunk needs support from prevailing winds. Drive a stake into the ground on either side of the root ball but well away from the trunk. Tree-ties, usually two are enough, should be loose enough to allow the trunk to move. Tie these in a figure of eight and use something soft, such as pantyhose.

Your gorgeous new specimen tree now needs a thorough watering. Gently fill the soil-dish with water, making sure you don’t wash away the formed walls. You must water regularly during the first few months following planting and don’t let the soil dry out.

Mulching, about 50–75mm deep, will also help to retain moisture but do not let the mulch sit right up onto the trunk as it could cause rotting.

And a final word
Trees are a lifetime investment and become an important part of a garden’s structure. You want to choose a tree suitable for your locale, one that will look good, grow well and be suitable for the size and design of your yard. And remember, size doesn’t just refer to the height of the plant. You also need to consider the width of the canopy and the spread of the tree’s root structure. In short, when selecting a tree look for the perfect tree and you will be rewarded with a valuable enhancement to your garden to be enjoyed for many years to come.

Pruning Trees
• Trees do not need a lot of pruning but you can remove any dead or damaged branches, stubs • and badly placed branches, such as those that are crossing and rubbing against each other.
• Remove any thin, weak side-shoots on the trunk of established trees, cutting flush with the • trunk using sharp secateurs.
• If you use a pruning saw on the thicker branches, ensure the cut is clean and smooth. Trim • the surface and jagged edges with a sharp knife. Large cuts should be sealed with a tree-wound dressing to prevent disease entering the wood.
• Cut back to just above a bud or joint to the parent branch, ideally at a point where there is • a side shoot growing in the same direction.
• Most deciduous trees should be pruned in winter while they are dormant. Take care not to • cut out old wood that will bear flowers the following spring or early summer. To avoid this, flowering ornamental trees such as peach and cherry should be pruned immediately after they have finished flowering.
• Evergreen trees need minimal pruning, but where this is necessary it is best done in early • spring or after flowering.