A guide to growing and planting trees

A guide containing tips, advice and observations drawn from the experience gained by Trevor Blamire over the past twenty-five years whilst propagating, planting and growing indigenous trees in the Southern Cape of South Africa.

 

A few misconceptions regarding indigenous trees

Indigenous trees are slow growing

A correct choice of species, planting methods and appropriate aftercare enable indigenous trees to attain surprisingly rapid growth rates from 1 metre to 1,5 metres per year.

Indigenous trees are robust and may be planted anywhere, in any location

As robust as indigenous trees are, individual species can be pretty fussy about their choice of habitat and may either languish on for many years or soon wither and die if planted in an unsuitable position.  Indigenous trees may be planted without any soil preparation and left to fend for themselves. 

Indigenous trees respond positively to the correct soil preparation and reward the initial investment with rapid and vigorous growth if treated well thereafter.

Indigenous trees do not require watering after planting

They require regular watering during their settling down phase over the first year or two – thereafter far less. During times of drought even established trees, if they are not adequately mulched, require watering.

As long as its indigenous, it’s OK

The operative term should be “locally indigenous”. Thorn trees from the Karoo are indigenous but do not belong on this side of the mountain and can become invasive under certain conditions.

The lush green growth of our natural forests indicates that our local soils are rich in nutrients

Most of the nutrients contained within our indigenous forests are tied up in the trees themselves and in the compost layer on the forest floor. Our Southern Cape soils are shallow and generally poor in structure, nutrients and trace elements. For good growth results our soils need nutrient and trace element supplementation, preferably of organic origin

“He who plants a tree believes in the future.” — Old Chinese proverb

Background to planting

It is important to select the correct species of tree for a particular planting location in the garden so that it may adequately perform the future function required of it.

No guarantee about looks

Tree clients often approach me with a pretty picture in a glossy tree book showing a mature specimen of just the right size and shape that meets their needs. This is a difficult, if not impossible, requirement to meet as there are many variables which come into play during the growing life of the tree which will determine the final outcome of its shape and size.

I have observed trees growing in the Karoo mountains which barely resemble their counterparts near the coast. Unfortunately trees do not come with a technical specification with which they comply. 

The problem that many a gardener is faced with is that they normally wish for their tree to grow as rapidly as possible to a certain size and shape and then stop. This is not possible, nature just doesn’t work like that.

With the exception of the pioneer “Keurboom”, the general rule of thumb to apply would be – “The faster they grow, the bigger they get”.

Tree “living conditions”

After planting, indigenous trees tend to direct their energies more towards lateral growth in order to stake their claim on as much of the available light gathering area as possible. They take kindly to pruning.

From the form and layout of our natural forests it can be gathered that indigenous trees are gregarious and like to keep diverse company. The strength of the natural forest lies in its species diversity and the mutually beneficial relationship which each different species gains from its neighbour and the slightly different contribution that each individual is able to make towards the “whole”, namely the the forest. Only a few species may be judged to be content to grow in isolation and these tend to be the hardier ones.

It is recommended that consideration be given to planting indigenous trees in groups, close together (1.5m to 2.5m apart), with the hardier species planted on the Northern and Western sides of the group. This provides for a quicker impact in the garden and enables the trees to establish their own micro ecosystem whereby they provide some degree of shelter and protection for each other.

Study your local environment and research which species occur there naturally – i.e. those that are “locally indigenous”. We have a responsibility towards the environment, which is threatened by most of our activities, to do what we can to preserve and honour the integrity of its specie’s distribution.

Soil characterisitics

Examine the characteristics of your soil to determine whether it is rocky, sandy, loamy, saline, has a high clay content, is pure clay or whether it is well or poorly drained. A number of different strategies may to be applied to cater for these different conditions.

When in doubt take a soil sample and have it analyzed. The soil pH plays a major role in controlling the uptake of nutrients by plants and a pH of approx 5,5 is recommended. Do not be tempted to radically alter the soil conditions at the tree’s planting locality in order to attempt to suit it. Sooner or later the tree will outgrow the confines of the planting hole and then be forced to cope with the soil conditions around it.

The condition of the tree

Carefully examine the tree before buying. Lush crowns may well be the result of excessive Nitrogen based chemical fertilizer feeding without any thought having been given to the health of the tree’s root system. Keep in mind that the tree’s foundation lies in its root system which may be more than twice the size of that which is visible above ground.

Take note if the tree seems to be excessively tied to a stake. Undo the ties and check whether the tree is able to stand upright on its own. The chemical growth stimulants used by some commercial growers are directed towards pushing the tree to a saleable height in as short a time as possible. Such trees often turn out to be rather “slap” (limp) and are sweet and juicy in sap and soft and weak in structure. They are adversely effected by strong winds and when newly planted out in your garden are particularly vulnerable to a variety of unwelcome plant pests and other such suckers of sap.

Pesticides

Be wary of the perfect specimen with not a bug or insect damaged leaf in sight. These leaves are usually the result of a particular nursery employing a pre-emptive pesticide spraying programmes, which are often unavoidable due to the intensive growing conditions that commercial nursery plants are subjected to. Unfortunately such spraying programmes, besides protecting the tree from all the bad bugs, indiscriminately kill off all the good ones as well and results in the plant’s immune systems becoming weakened. Trees grown in this fashion are vulnerable to many pests and diseases once leaving the protective confines of the nursery, forcing the gardener to continue to apply pesticides. 

When planted out, such trees can suffer a setback when being subjected to a belated “natural selection” process. Nature does not cater for the weak and infirm, nor does the “natural selection” process stop at some point along the way.

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