Free roots will grow outwards as far as their branches, and often more than the area covered by their branches (called the canopy). With Fir trees this is not likely to be very far, but with Saman trees the spread of roots will be enormous because the head of the tree is enormous. As you stand in the garden under an umbrella in the pouring rain, or make your way along one of the city streets in a deluge, consider this sentence and look at the trees that surround you. In my home we have a variety of umbrellas of different sizes to give protection from the elements. So it is with trees, which act in much the same way as umbrellas. In Georgetown many of the trees form such large heads that they have to be pruned regularly to keep them balanced. In other words, they have the spread of their canopy reduced. This means that they do not have to send their roots out so far. Now it is a fact that the ground area under the canopy becomes dryer than the surrounding area because the main volume of water is shed outside the ‘circle’ formed by the branch system and leaves in the same way as the umbrella, but with trees their root growth has to match and exceed the growth of their branches to make sure that the tree gets sufficient water to sustain growth. If it doesn’t, it will die out.
You will all have seen gardens which have large trees with their roots coming to the surface of the lawns. This again is because they have to go searching for water in more open ground. Look at the ground under a Saman tree. You will find it as hard as a rock throughout the year, and the root spread just as enormous as the spread of the canopy. At the moment I am talking about most of the trees we find in Guyana’s towns and cities. Now in Europe, where the vast majority of trees are deciduous, for the winter months the rain which falls during wintertime falls onto the ground right up to the main trunk of the tree because there are no leaves to bounce it well away from the tree. Consequently bulbs such as snowdrops, bluebells and so on are able to get to a water supply in the late winter in order to start off their growing season, and they are able to flower in profusion in the spring under trees before the canopies become too dense. During the summertime the woods of deciduous trees in Europe suffer from the same shortage of water as do trees here, and have to send out more roots in search of it.
Under large trees in Guyana we find that different kinds of grasses become established. Not the fine-leaved grasses we find so desirable for our lawns, but coarser varieties able to stand drier conditions and reduced lights levels. They compensate for lack of light by longer and darker green leaves to get as much light as they can. With trees having light foliage like the Jacaranda, for example, their roots are not so invasive because the foliage is not so dense to prevent water going through it. If you have a smallish garden it is important then to choose only those types of tree that will not develop a massive root system in order to survive. Leave the Saman and the Flamboyant trees to those that have the space.
Is there anyone out there who has a plant of Tillandsia cyanea? This blue-flowered bromeliad is a marvellous addition for a collection. Perfect for this climate. I remember seeing it at a nursery some years ago for just $600. One final word, dear readers. Don’t take any risks with seedlings which sometimes have the alarming habit of’ ‘damping off.’ Patches of seedling suddenly dying are often affected by fungus diseases at soil level and sometimes whole trays full of youngsters will keel over and die. Use sterilized soil, don’t over water, and water on one of the copper sulphate mixtures tailor-made for the job. Enjoy your garden and may your God go with you.
