Welcome Autumn Leaves

March 20, 2015

Im excited.  You may think its because the school holidays are and Easter are just around the corner but that’s not the reason. I love autumn but that’s not it, nor is it the Cricket world cup.  Im excited because the Melbourne Flower and Garden Show is on again next week.  This year marks the 20th year of what has become the greatest garden show in the southern hemisphere.

MIFGS is staged in the wonderful heritage listed Royal Exhibition Building and the surrounding Carlton Gardens from 25th till 29th March.  As it’s the 20th year this year’s show promises to be pretty amazing.  If you have never take the opportunity to head along make a plan to attend this year’s show.

Autumn is colouring our towns beautifully as it does each year around this time.  We had some rain this week from some passing thunderstorms which greened up the lawns and gardens and encouraged the veggies.

Autumn also brings my favorite things.  Yep you guessed it – autumn leaves.  If you did year 9 science you will remember  photosynthesis.  This is the process that converts energy from the sun into food for plants.  Plants take carbon dioxide from the air, mix it with water and hey presto turn it into glucose (yep sugar) and oxygen which they breathe out.

When you think about it photosynthesis helps to create most things we use as a civilization.  Plants use the glucose produced to fuel the production of wood which we use to warm ourselves build with and mae paper from, tomatoes and other foods, cotton which clothes us.  Even miners use paper made from plants to draw maps and make notes.

Plants leaves are specially set up to do this of course.  They are generally flat and broad with a layer of cells only one cell thick on the outside.  These cells are called the epidermis and are clear so they let light in to the cells beneath that contain chloroplasts.  The chloroplasts contain a green pigment, called chlorophyll.  The chloroplasts are like little factories within each cell which pump out glucose.  Plants also contain accessory pigments which assist with photosynthesis.  Carotenoids are the most important group of accessory pigments.

Glucose made in the leaves can be made into cellulose for plant cell walls or stored as starch till it is needed.  All the oils and proteins and scents and colours made by plants begin this way.  We all know glucose.  It’s a white coloured sugar Mum used to stir in lemonade when we were sick when we were kids.  As for cellulose (the cell walls) well this paper you are reading now is made from cellulose.  How great is that!

In the plant leaves there is some amazing chemistry happening.  One plant leaf is made up of thousands of cells and each one contains 40 to 50 chloroplasts.  The water molecules are broken down to its components of hydrogen and oxygen.  It sounds simple when you just read it but consider this.   If we had to split water ourselves we would have to heat it up to 2000 degrees centigrade to make it happen.  Plants do it at room temperate with no fuss at all.

Ok so now some of the oxygen is breathed out as I said.  The hydrogen though is combined with carbon and some of the oxygen by enzymes in the chloroplasts.  The result is glucose.

Green leaves are green because of chlorophyll.  When autumn, shorter days and cooler temperatures signal changes.  Chlorophyll molecules start to break down and are not replaced.  With the green colour gone we see the other secondary pigments.  Carotenoids break down more slowly and can be  yellow, orange and red.   These colours have always been there, they were just masked by the green of chlorophyll.  Carotenes give carrots their orange colour and make tomatoes red!

To get the best display of autumn colours you need to make sure you provide these conditions.  Trees need good rainfall in the summer growing season, sunny autumn days which we’ve been having, cool nights (check), close to but not freezing which would kill the leaves, reasonable autumn moisture so leaves can still grow well into the season and calm days so the leaves remain on the trees.

So far this month we are down a bit on moisture but dew and hand watering counts.  The cool nights are starting to happen so all we need now is a tad more rain over the next month or so and we should still have a great show.

If you are looking for some autumn foliage trees have a wonder around and look for the ones you like.  Do some research and make sure of their final size and shape.   If you are in a new home consider planting some trees.  Contemporary gardens with grasses and foliage plants look great but you can incorporate some stunning autumn foliage trees which will give you great shade in summer, add proportion to your landscape and provide some wonderful autumn leaves which you can mulch to improve you soil.
A landscape with mature trees can add thousands of dollars to the value of your property.  All you have to do is plant a tree.  Give it some water to get it started and the plant will do the rest of the work for you.  Just think, every day the sun shines the plants in your garden perform their miracle and grow.  As your autumn tree gets bigger so does the value of your property.  So why not get the magic of chlorophyll and plant chemistry working for you in your garden.  Plant some autumn trees, then collect the leaves for your compost

If you need a hand to decide what to plant this autumn give me a call at TOP hEDGE.  Till next week, Happy Gardening!

At TOP hEDGE our Horticulturists and Green Gardeners know all this and mulch more ways to make you garden thrive in our conditions, so if you love your garden but never have enough time give us a call on 5330 1071.