This article explains how to plant with the right positioning for a plant's above and below ground needs, and conserve water when you transplant. The last article dealt with water-wise planting arrangements and lawn replacements. The next article after this will be about mulching.
Before you choose the actual plant species to plant, consider your soil's nutrient status. Different Mediterranean climates may have similarities but their soils and geology are of course much more diverse. Choose plants for your soil rather than seeking to change your soil with additives and irrigation. The soil nutrients, soil type, drainage, subsoil water, rocks and walls and sunshine will help you decide how to plant and what to plant.
pH tests are relatively inexpensive and can be bought at nurseries and pet shops. You can do a soil-type test in a bottle of water. I described this previously and here is a pin at the bottom of the page. For the rest, operate according to your budget. Multi-mineral soil tests are expensive, for me that is a few thousand rands, or hundreds of Euros or dollars. A chat with neighbours who are farmers or keen gardeners may clear up questions on soil deficiencies in your area. Above all, do not add artificial fertilizers in dry gardens.
According to Gildemeister (1995:74) in Mediterranean Gardening: A Waterwise Approach, too much nitrogen encourages spindly growth and bulb decay. This is doubly true for Cape plants. Indeed Van Jaarsveld (2010) Waterwise Gardening in South Africa and Namibia advocates avoiding synthetic fertilizers in order to be water-wise. The alkaline calcareous soils of the Riviera also increase the soil concentrations of Potassium and Phosphorous and tax plants, so do not apply these minerals to your soil when growing South Africa plants which come from very leached soils. The connection with water saving is that the closer you meet the nutrient needs of plants, and that context informs you what and how to plant, the less water they require.
Drought tolerant plants require careful positioning for above and below ground conditions according to Gildemeister (1995:62). The more you exploit the garden microclimates the better you will meet their needs.
Inform yourself on the plant’s demands for light. If they need sunshine but not intense heat, this will help you decide how to plant them. This demand is best fulfilled by planting under tall moving shade supplied by big trees with high canopies and bare trunks, like palms or umbrella pines, or trees which have been shaped to produce high shade.
Afternoon sun is the most stressful sunshine, so plant sensitive plants to the east of barriers, or on south facing slopes and walls.
Reserve the hottest locations for Cape plants.
Use twig or branch wigwams to shade small new plantings. It is interesting that Gildemeister mentions wigwams. They are very effective during transplanting, as I learned when working for a master vegetable garden designer.
The soil depth should also tell you how to plant and which plants to choose. Match the soil depth to the plant’s preferred form of root structure. On rock or in shallow soil choose superficial rooters (Gildemeister 1995:64).
Many European Mediterranean plants survive with less stress if they have a cool root run, near a rock, or a wall.
Soil moisture is preserved in places protected from drying out like southern slopes, plant shaded places and hollows.
The underground parts of South African plants like a good bake during the dormant season, Gildemeister says, so make sure they don’t get damp during summer. I must add this is in the context of growing our plants in Europe. My mother found that many of our geophytes have mechanisms to protect themselves from too much heat, actually, which they may often experience in our climate. They may have retractable bulbs which burrow deeper during summer.
Always supply adequate drainage for drought tolerant plants that require it. Poor drainage shortens the life even of European Mediterranean plants like bay. Plant cushion plants or plants that love good drainage on terrace walls, and trees at the back of terraces where there are cool root runs.
Where water gathers plant those which like soggy winter roots.
Mediterranean plants grow roots in spring or autumn, therefore plant with the first winter rains. Also plant Mediterranean bulbs in autumn, for later summer baking. Spring is for planting out tropicals, be careful of their winter dormancy, which can cause roots to rot if the area is wet in winter.
You can save water by transplanting correctly because if you reduce root trauma you don’t need to overwater plants for them to survive while they are taking. Gildemeister (1995:64) advocates always digging a generous planting hole, and Van Jaarsveld (2010) a hole twice the size of the container.
My mother during her years of forest conservation activism, and the Parks Board with whom she had contact, found that the smallest possible hole that can accommodate the root ball actually works better. It is a new trend in tree planting called 'free root planting' and was featured some years back in the British Horticultural Journal. It is not well known and a google search will not produce hits. It involves minimal disturbance of the roots and minimal breakage. Rocks are packed around the seedling and these conserve water in the soil around the roots both through cooling the soil, and through their weight and the increased supply of accessible water this creates.
Gildemeister suggests that one water
in the holes before planting, which also allows one to assess the soil
drainage. If after an hour the soil is not fully drained, choose plants which
tolerate wet feet. I’ve found that this is a good idea. I water plants and the
soil they are going into thoroughly, transplant and firm the soil very very
gently to reduce root hair breakage and then don’t water after planting for 24
Dig the new hole before digging up the plant to be transplanted and
exposing it to dessication. To reduce transpiration from the leaves during the
shock phase when many root hairs are lost, shorten the branches by a third, and
conserve fine roots by being gentle. Gildemeister recommends firming the soil
around the plant and watering it in to make sure of root breakage.
You can foliar feed if roots have suffered. Gildemeister gives a good tip for wind resistance. Place the strongest root in direction of prevailing wind and stake young or top heavy plants in windy places. Plants can take one to two years to establish.
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