Green Roofing on a Massive Scale

I have written about the benefits of Green Roofs before, especially for us in South Africa, with our extremely warm climate. The insulation and resulting cooling effects that it would bring are huge. They can be beautiful at the same time as functional.

The Vancouver Convention Centre is an amazing example of what can be done.

Getting Control Back From The Aliens

Getting control of Alien vegetation is an important subject for any gardener in South Africa. Our water resources and indigenous plants are under threat, and we all need to learn to identify and remove invasive plants whenever we find them. Fortunately, we have a little help that reminds me a bit of the plot from The War of the Worlds.

The other day, while driving, I spotted a very unhappy Opuntia growing on the side of the road. It looked as if its life had literally been sucked out of it - and looking closer, it had!

Thousands of tiny bugs called Cochineal insects had latched on and were pushing their little beaks into the plant. They were quite rapidly killing the plant by sucking the sap out of it.
This way of dealing with weeds is called biological control, and South Africa is one of the top three countries in the world when it comes to this method of invasive plant control. Since 1914, we have introduced over 80 species of biological agents in order to control or destroy the invasive plants that thrive in our ideal conditions.

The concept behind biological control, is that because invasive plants are in a very strong position in a new environment with no natural enemies, the playing fields need to be levelled. The best way to do this is to introduce their natural enemies from their countries of origin. this either destroys, or helps manage the burgeoning alien populations.

Biological control is an ideal way to get rid of invasive weeds, because:

1. it causes no pollution and affects only the targeted invasive plant
2. it is self-sustaining and as a result, permanent
3. it is very cost-effective
4. it won't disturb the soil or create barren areas where other invaders could establish, because it kills the targeted plants over time, and allows the natural vegetation of the area to recover gradually in the shelter of the dying weeds.

Obviously these biological agents need to be introduced extremely carefully, and there are very strict controls in place to make sure that there are no unforeseen results. It doesn't work in all situations, but there has been excellent results with Water Lettuce, Port Jackson Acacia, Red Sesbania, and of course Opuntia.

Something else to think about, is that this little Cochineal insect can also be harvested to make a crimson dye which is sometimes used in food colouring. Try not to think of that next time you're eating food thats been dyed red!

Common Trees with Aggressive Roots

This is a problem I've touched on previously, but I'm amazed at how often people plant or leave trees with strong roots to do their damage. The initial title for this post was going to be: Warning: Trees With Evil Roots. But I can't really call them bad can I? These trees have amazing roots, and as a result they are usually very fast growing, are often able to shrug off many diseases and pests, and are able to withstand drought easily. So really, they are incredibly well-designed plants.

But the problem comes in when they are planted near drains, walls, paving, or in small gardens. The following trees are just the most common trees that I see mistakenly planted:

1. Ficus (Fig tree)
   
2. Erythrina (Coral tree)
   
3. Cussonia (Cabbage Tree)
4. Schefflera (Common Cabbage Tree)
   
5. Caesalpinia ferrea (Leopard Tree)
   

These all have the tendency to damage pathways or drains if planted too near. A couple of restaurants in Durban (Manna Restaurant & Churchill's Coffee Shop) have planted groves of Leopard trees in their outside areas, and while they're great at the moment to sit under, they are doing huge damage to the drains below.

Leopard Trees - Soft and Aggressive

I also often see damage to walls by plants that expand outward, putting pressure on foundations and walls. They are planted when they are still small, but in time get much bigger than anticipated. Some of these are:

1. Chrysalidocarpus lutescens (Bamboo Palm)
2. Strelitzia reginae
3. Many palms are planted while still small, but get much thicker.

Are there any plants that you've noticed in your part of the world that need warning labels?

The Do's and Don'ts of Planning Your Front Garden

I don't believe that first impressions are always lasting impressions - If that were the case, I think my in-laws would have probably talked my wife out of marrying the long-haired, bare-footed mess that I was back then? Fortunately for me, they looked past my initial appearance.

Is this really the best decision? What a bleak first impression!

Unfortunately for most people though, the front garden is the first, and only impression people have of your home. Very often we pay so little attention to the front garden, and rather save our energies and efforts for the inside of the house, and maybe then we look at the back garden. Often the front garden is last on the list.

When my wife and I were looking for a place to buy, we would often pull up in front of a potential place, and make a decision whether to go in, entirely based on what it looked like from the road. We may have lost out on some gems by evaluating things this way, but we saved ourselves a lot of wasted time too.

The front garden doesn't have to (and probably shouldn't) require a lot of maintenance to keep it looking good. To achieve this though, a lot of thought and planning needs to go into it in order to save you work in the long run.

There is a definite move away from lawned verges - (a) because they need a lot of water, (b) because they're boring; and (c) because they constantly need to be cut.
A better solution would be to use groundcovers that need very little water to look their best, and don't need to be cut. Once established, they will even prevent weeds from establishing themselves.

I love this garden. Its simple, beautiful, and low maintenance!

Another option is to plant wild grasses. Just because they are 'wild' doesn't mean they have to look a mess. You would also be supporting an environment for all kinds of birds, that you wouldn't ordinarily see in your garden. I've written about them in a previous post, and used them in a front garden.

In the USA, in some states there are subsidies available if you convert your front lawn into a more sustainable garden. And many people are even going so far as to convert their front gardens into edible gardens.

The things to keep in mind when planning your front garden, are:

Keep things simple - You're not likely to spend a lot of time out the front of your house, so there is no need to put in a lot of detailed planting - also most people will see it only as a blur as they drive past. I think most front gardens should be quite 2 dimensional (like a painting or snapshot), because they are generally only viewed from one angle. You should be able to look at it for just a second, and have a great impression in your minds eye. If you achieve this, I think you have succeeded. There are always exceptions to the rule though.

The less work, the better - Save your time and effort for the areas of the garden that you will use the most. Get rid of lawns, and high maintenance pruning work. Plant good low maintenance alternatives instead.

Keep watering needs to a minimum - again this will save you time and money, and will help the environment at the same time.

What is next door? - Look at your neighbours verges, and look at what you can repeat in your front garden. Try to steer clear of just doing your own thing - your garden and neighbourhood will look better if it blends in well with its neighbours. Look for next door trees or plants that you can bring into your garden, and I mean buy your own. Your neighbour might be suspicious if he sees a similar plant appear in your garden to the one that used to be in his.

If in doubt call an expert - Call a landscaper/garden designer if you need any help. You may have to pay a consultation fee, but you can often get very good ideas, and good guidance in the beginning, and you will reap the rewards in the long run.

There are all kinds of options and possible ideas for your front garden - so why not explore some of these? You might find that you want to spend more time admiring your house from the front along with the rest of us?

Earth Hour

I'm not sure if you've heard any of the hype around Earth Hour, but its an amazing initiative by the World Wide Fund, encouraging every individual, business and community to take a stand against Climate Change. To show your support, you need to sign up and commit to switching off your lights for one hour on Saturday, March 28th at 8:30pm.

It started in Sydney, in 2007, and had around 2 million people coming together to switch off their lights for one hour for this vital cause.

In 2008, that number grew to about 50 million. Global landmarks like Golden Gate Bridge in San Francisco, Rome’s Colosseum and the Coca Cola billboard in Times Square, all switched off in support of Earth Hour.

This year, 2009, Earth Hour will see the lights go out on some of the most recognised attractions on the planet, including Cape Town’s Table Mountain, Christ the Redeemer in Rio de Janeiro, Merlion in Singapore, Sydney Opera House, the iconic 6-star hotel, the Burj al Arab, in Dubai, Millennium Stadium in Cardiff and the world’s tallest constructed building, the Taipei 101.

Earth Hour 2009 has one major aim: to unite the citizens of the world in the fight against climate change in order to convince governments and world leaders that our planet cannot wait any longer. There simply isn’t enough time, and therefore 2009 is a colossally important, if not the most critical year, to take action on climate change.

Click here to join.

Indigenous Beauties : Leucosidea sericea

This is a small tree that I've been wanting to put the spotlight on for a while now. Its common name is Ouhout, which directly translates as 'old wood'. It probably gets this name from the way the trunk and specifically the bark looks old and wizened.

Leucosidea sericea
Ouhout

It is an extremely fast growing, evergreen tree that gets to about 5m in height, it loves full sun, and is often found near rivers or streams. It is best planted in groves and preferably where the bark can be truly appreciated. Even its soft and serrated leaves are beautiful, and release a strong aroma when crushed.

Its flowers are light green to yellow, and appear from Spring to Summer.

It will handle frost easily, but doesn't take well to dry conditions. It would normally grow at higher altitudes - it is quite common along rivers in the Drakensburg.

Behind The Scenes - Steeply Sloped Garden

We've just finished some landscaping for a wonderful couple in Durban North. They were very trusting in giving me quite a bit of freedom in the planting and design, but also had some good ideas that helped guide me in giving them what they wanted.

Their aim is to create as sustainable a home as is possible. They will be harvesting their natural run-off from their roof, to use in watering their garden. Solar panels on the roof help provide electricity. So the next project was the garden. We needed to create a balance between water-wise planting and still create a beautiful garden. Bearing in mind that the soil on the verge had been washed down the road in a previous thunderstorm, and therefore needed to be retained with strong plants.

The home was on a steeply sloped piece of land with magnificent sea views. The problem of the steep slope had been solved by creating a series of terraces with retaining blocks. The verge was still quite steep and the planting needed to be carefully chosen. The drawings below, show the level area near the house, with a patio, and water feature, that is positioned to make best use of the views.

The terraces drop away below, down to the verge, and the road. On the terraces, we decided to plant masses of the same plant on each level to create an impact when looked at from the top.

On the first terrace we planted Salvia leucantha, which has mauve and white spikes for flowers. The next level was a mass of grass - Melinis nerviglumis, with the start of a grove of Indigofera frutescens, and Grewia occidentalis.

This then carried through to the verge, which was a swathe of Aristida junciformis grasses, and Asystasia gangetica groundcover below. Both of these are great at holding soil, and also are fast growing. The grove of trees will help disguise the security fence, but neither the Grewia or Indigofera get high enough to block the views.

We piled in masses of compost, which would help bring nutrients back into the very sandy soil, as well as help speed up growth.