The epitome of gardening must be growing trees for without them the whole cycle of plant life would be under constant threat. They are the foundational pillars of any good garden design and dictate the landscape once they're planted and growing. For with their immense canopies they can reduce the garden to a shady retreat or open the yard up to winter sun.

Yet, what does one look for when they go to buy trees? They all look very similar when stockpiled throughout the nursery but how can you tell a good one from a bad one? Are there giveaway signs that the tree you just bought was, in fact, a 'lemon'? Sure there are, and here a few that may help you buy the best tree and leave the rubbish where it belongs.

• It's all about shape - isn't it always? The tree's structure is an important element when considering which tree to buy. It should have a main stem with 2-3 leaders branching off midway up the trunk. Some nurseries will sell them with just a single trunk and not reduce the leader at all. It's hard to tell, from a gardener's point of view, whether this is a good tree or not because it obviously hasn't suffered any pruning yet.

  My tip would be to leave these for the garden centre to deal with and buy the ones that have already proved they can survive cutting back. This will ensure that your new tree will have greater success when you plant it in your garden.

• Is it root-bound? - Check around the base of the container and look for any roots that are forcing their way through the pot. Also, you can try sticking your fingers down the edge of the container or a key, or other object, into the middle of it. If roots are showing at the base or the soil in the pot seems impenetrable then it's a sign that the tree is root-bound.

  This doesn't mean that the tree can't grow successfully but it does highlight the need for extra care and patience in trying to get it established. If you're looking for a easier alternative, bypass the trees with root congestion and find an alternative with a better root structure.

• Foliage telling you anything? - as foliage usually plays an important part in most trees growth success, listening to its leaves can save you heaps of time and money. Look for brown edges - a sign that water is lacking or there is some mineral deficiency in the soil; lumps on the leaves - exhibiting signs of pest infestations or even a myriad of other foliage issues.
• Price - trees seem to be one of those items that command very different prices in the market place. I've often found the same tree for a much cheaper price at a nursery in the same neighbourhood. Apart from the price there is no other apparent difference so for me I would much rather save the dollars.

While those were some general buying tips there are also many other factors that need to be considered. A tree isn't as flexible as your favourite garden shrub and it can't be moved, or removed, as easily as a container plant on your patio. Forethought is much better than hindsight.

Here are four more things for you to consider before you buy trees for your garden;

1. Small vs Tall - the problem with trees, like puppies, is that they grow up. While they may start life all cute and cuddly it's not long before you could have a monster on your hands wreaking everything that you once enjoyed about your garden.

   A small tree is one that will grow to about 5-8 feet. Medium sized trees usually don't exceed 15-20 feet and tall trees can break into the stratosphere like the sequoia - well almost.

   So, when you buy a tree, choose one that will fit within your surroundings in 10-15 years not just on the day you plant it.

2. Evergreen vs Deciduous - do you enjoy raking leaves? No? Then stick with an evergreen. For the novice, a deciduous tree is one that loses its leaves during winter while an evergreen...well...remains evergreen.

   I often get asked why would you buy a deciduous tree. For many reasons, really. Firstly, its shape and structure make a real impact in the winter garden, while the seasons either side produce spectacular displays as well. Then there's also the added advantage of planting them on the west side of your living areas to let sun in during winter and shade throughout the warmer months.

3. Exotic vs Native - There has certainly been a trend over the last decade to search out indigenous tree species rather than their exotic counterparts. The reason, I guess, is that natives take far less effort to maintain and if they're already growing in the region then there's probably more chance of success.

   Exotics - I'm using this term to describe trees that you won't find growing in your area - can often take longer to establish, are much more prone to local diseases and pests and are usually more expensive than natives. But then the rewards of growing exotics are that you can show off your own individual talents and produce a garden that is distinctly different from your neighbours.

4. Fruit vs Ornamental - an even greater trend is starting to develop in the tree buying arena than just the popularization of natives. It seems that more gardeners are planting fruit trees over ornamentals as their garden plots get smaller and as the desire to be more self-sufficient grows.

   Ornamental trees are wonderful, in that they provide beautiful aesthetics to the garden but enjoying the produce from your own fruit tree is hard to contend with.

Of course, once you've bought your tree you're going to want to know how to plant it. Fortunately, some tips on how to plant a tree already exist. Aren't I good to you?