Green, green, green

One of the main advantages of living in a residential estate is that – usually – you are surrounded by significant tracts of open land. And very often that land will be left in a relatively natural state. This is a good thing for a whole lot of reasons.

All plants are good

Firstly, many recent studies have shown a direct correlation between mental health and easy access to natural open spaces. The only surprising thing about this is that it needed to be researched in the first place. It’s something we all know intuitively. And, secondly, we are rapidly becoming more and more aware of global climate change and that green plants, which flourish in natural open space, are effective carbon sinks. So they are essential for our continued existence on this planet.

But spekboom is more than good

But we live in an unequal world, and not all plants are equal. While expansive tracts of landscaped lawns, rose gardens and exotic flowerbeds look pretty, and are undeniably green in colour, they use vast amounts of water and – quite honestly – do not really pull their weight in the carbon sequestration game. So most estates are now concentrating on restoring natural vegetation as far as possible, and planting mostly indigenous water-wise plants. And one of the plants that is getting lots of attention lately is the humble, unassuming but truly remarkable spekboom (Portulacaria afra).

Spekboom grows in many parts of South Africa, including the very arid areas, but it is most at home in the valley thicket biome of the Eastern Cape. It’s the dominant plant in the Greater Addo Elephant National Park, where it is a favourite food for the large herds of elephant. One of the reasons it can produce enough biomass to feed these huge animals is that it is particularly drought-resistant, and particularly skilled at converting atmospheric CO₂ into sugars. ‘Big fat hairy deal,’ you may say. ‘All plants do that.’

What makes spekboom so special?

True, but, without getting too technical, spekboom has elevated photosynthesis to a fine art. All plants photosynthesise during the day when the sun is shining, there is plenty of water about and conditions are good. But when it’s dark and dry, and doom and gloom hover, they tend to curl up their little leaves, retreat into themselves and hope for better days.

Not spekboom. This cheerful, bright green plant can photosynthesise in the usual, very efficient way when times are good, but when there is very little water – I promised I would not get too technical – it changes to photosynthesising at night, using a different chemical process and thereby conserving water but continuing to create food for animals (and people) and to suck CO₂ out of the atmosphere.

It gets better, though. In nature, spekboom grows into a slightly untidy bush that spreads laterally, slowly covering all the ground with a succulent green ‘skirt’. And, underneath that skirt, dead leaves and stalks create a mulch that slowly returns the carbon the earth. And – how cool is this? – it doesn’t burn. And, as branches break off near the edges of the skirt, they take root and become new plants – spreading further and further. In fact, it grows exceptionally well from cuttings. Just break off a small twig, strip the leaves from the bottom, plant it and water it – and that’s how it spreads in nature. Most wild animals, including kudus and elephants, browse spekboom from the top, leaving the skirt to develop. And, even better, as they reach across, they break off a few branches that fall to the ground and – within the shelter of their mothers’ skirts – form new baby plants.

Interestingly, one of the main reasons spekboom has died out in many parts of its natural range is because of the introduction of domestic animals, especially goats. Goats – and to a lesser extent cattle – graze spekboom from the bottom. This destroys the skirt, and causes it to grow into a tree, rather than a shrub. And, because it does not have a skirt spreading out, it can’t form new plants. And the leaf litter, instead of forming a carbon-soaking mulch, just blows away in the wind. So, instead of a thicket, you get large trees separated by barren, dry earth. And when the trees die, they leave no heirs to continue their work.

But those trees, while they are not a good sign in nature, are rather beautiful – rather like giant bonsais. So – not surprisingly – spekboom is a very popular bonsai tree. Again – you’re not going to save the world by having a few bonsai spekbooms, but they’re beautiful and worth having – especially if they have lots of cousins growing wild along the jogging paths and MTB trails of the estate, and  especially if you have a few kudu or other antelope wandering about.

In order to reap all the benefits of this amazing plant, it’s best left to its own devices to form a skirt, and to spread laterally. But even neatly trimmed spekboom has some advantage in that it is extremely water-wise, and – even in severely dry conditions – will continue to photosynthesise and stay green.

How to make spekboom work for you

So, let’s recap. We have a plant that needs very little water, fireproofs the land, is an excellent feed for game, is a pretty bright green with delicate lilac flowers, and – tadaa! – will save the world by sucking up carbon. In fact, if you plant enough of it, you can sell carbon credits. So you should really consider spekboom for your open landscaped areas, and encourage residents to plant them in their gardens.

You can buy spekboom plants from most nurseries, but there are some, like the Spekboom Foundation, that specialise – perhaps proselytise would be a better word – in spekboom. www.spekboomfoundation.co.za

Caveat emptor

Before you run off and buy a whole lot of spekboom plants, take into account what the natural vegetation is in the area you plan to develop, or where your estate is situated. The local – as in local to the area, not just indigenous to South Africa – vegetation is almost always the best bet. But, even then, a neat hedge of spekboom can be a great, water-wise, carbon-sinking addition to your landscaped areas.