Trees: Solving Common Problems

A beautiful old native fig tree - showing evidence of getting a bit thin on top!

How many hats do you have?  On Saturday I had to put on one of the many I seem to juggle - this one was Di the arborist ( I also needed my thinking cap!).  Now, it's been a long time since I climbed a tree with a chainsaw hanging from my belt, but I can still tell a healthy tree from one under stress.  This one was definitely under stress.

Lisa and Marcus had called me up about their fig tree - we are talking about an over one hundred years old Moreton Bay Fig (Ficus macrophylla), a significant tree and one that they really love.  It is the focal point of their property, providing shade, branches to swing from and a sedate backdrop from the house.   Why did they call me - because it was dramatically shedding it's leaves i.e. the crown was thinning.

So what are they key things I look for when a tree is beginning to lose it's vigour?  This bit of detective work will help you solve the problem.  Here is a checklist that you can follow and WHAT TO DO TO REMEDY THE PROBLEM.

1.  How does the canopy look? This one was thinning - losing it's leaves.  Sudden decline, or death of a tree, is almost always a root problem - so think about what is going on there first.  Remember - the answer lies in the soil!

2.  How does the trunk look - any signs of splitting, cracking or insect attack (borers leave tell-tale holes , webbing and  sawdust). None of the above.  Splitting is usually a sign of excessive over or under watering (sometimes, but rarely, a lightening strike).

3.  Any recent disturbance to the roots or soil above the roots.  Yes, this had landscaping machinery running over it recently causing compaction.  Roots thrive on air and water.  If they are cut-off, disturbed, poisoned, compacted - THE TREE WILL NOT THRIVE.

Soil compaction all around the drip-line of the tree caused by heavy machinery

(It's amazing how many times I have been called out to a tree that is suddenly looking sick, only to find that the owners have; chopped through half the roots to build footings for a new building or swimming pool, had painters and builders in who have dumped their waste under the nearest tree, laid a new driveway or built a paved patio over the roots etc.etc.)
WHAT TO DO: The best way to remedy soil compaction problems is to aerate it.  Now you can do this by having a big garden party and asking everyone to wear high heels OR you can hire an aerator - a kind of roller with spikes on it.  NEXT you top-dress the area with a free-draining soil mix.  Most landscape suppliers will have a bulk top-dressing mix specifically for this purpose.

4.  Any signs of disease or insect attack to the leaves.  Yes, this had a common leaf sap sucker of figs - psyllid.

Evidence of sap-sucking fig psyllid

There are many different kinds of fig trees, and most of us are probably familiar with the delicious fruit from the edible fig-tree or the latex extracted from the tropical variety that goes to make rubber.  In our area we have nine figs that thrive in the rainforests - this is one of them - and they all have a tacky white sap.  Hence the sticky stuff left by this sap sucker as it munches into the leaf. It sticks to your shoes like chewing gum.  Under natural conditions psyllids are kept under control by birds and other insects that live in the leaf litter that accumulates under the tree.
WHAT TO DO: Think how the tree grows in it's natural environment and try to replicate it. 1.  Do not have grass growing right up to the trunk of trees - grass is thirsty - it competes with the tree for water and nutrients.  2.  Mulch under trees.  I saw this as a simple solution to solving a fig psyllid problem, some years ago, when I worked at the Royal Botanic Gardens in Sydney. Mulch also provides the right environment for natural predators of the psyllid. (Mulch had been put under part of the tree a year or so ago, but it needed to extend out further from the trunk and be replenished.

5.  Any environmental reasons for the tree to be under stress.  Yes, we have had a long, dry winter.
WHAT TO DO:  We are coming into out wet season so watering probably won't be necessary.  If, however, you have a long, dry period - make sure your large trees are mulched (this help to retain moisture) and that they are adequately watered.

6.  Check the pH levels of the soil around the tree.  This was about 7.5 - a little alkaline for a tree like this - probably due to recent building works and run-off from them.  In my experience, most soils around houses prove to be on the alkaline side - lime/alkaline products are a large component of concrete, mortar and other construction materials.

WHAT TO DO:  To correct the pH and give the tree a boost it would help to feed it.  Correcting any nutrient imbalance will also help to make it more resistant to pest and disease attack  Most of the feeder roots of the tree are around the drip-line so this is where you fertilize a tree. Going in a rough circle under the drip-line - dig holes, roughly the size a tennis ball canister, 1-2 m apart (depending on the size of the tree) and pack them full of an organic fertilizer.  Like this, they act as a slow-release fertilizer and keep feeding the tree over a long period of time.

Click on this link for CARE OF CITRUS TREES

Recipe: Mango Chutney

Thoughtful friends who know exactly what to give me for Christmas - a big bag of cow poo!

A hopeful, healthy and Happy New Year to the amazing 35,000 people who read this blog in 2012.  All I aspire is to is to give your heart some hope, your taste buds extra zing and more power to your green thumb!

I have been feeling sad - hence the quietness.  I lost my Dad in November - it's hard to lose people you love and you know who truly loved you.  Then, just when I returned to Australia, my dear friend lost her 19 year old son in a tragic car accident. A time for reflection.

However, it's hard to be sad with six grandchildren around.  There has been very little gardening done over the festive season, but lots of cooking, cooking, cooking!  Finally, they have all gone home and I can think about the coming year.  I am aiming for a little more 'me' time in 2013.  We'll see.

Mango tree with fruit about to ripen

One of the benefits of a long, dry winter has been the amazing display of all the tropical flowering trees - and this includes the mango.  It flowers around October and we hope for no big storms then as they knock the flowers off - and this means no fruit.  Not this year.  Shortly we will all be woken up to the sounds of mangos dropping on tin roofs - it sounds like a thunderclap.  These gorgeous trees are just laden with ripening fruit - happy days.

This is a recipe I have been making for many years to give as Christmas gifts.  When I lived in Sydney my dear friend, Sheila and I, would toil happily over a big bubbling pot of mango chutney.  Peeling and dicing mangoes is a messy business and it's always better shared over a cup of tea and a chat.  This works best when the mangoes are slightly green and you end up with some some residual chunks - instead of a kind of jam (which still tastes good!)


Mango Chutney
So, since it is very easy to make, here is a recipe which includes large luscious chunks of mango. It is really good served with cold ham, poultry or game – or, of course, any kind of curry.

This is, honestly, the best mango chutney I have ever tasted!  I have been tweeking it for about twenty years to perfect the consistency and flavour.

2.5 kilos of slightly under-ripe mangoes

700g soft light brown sugar

1 level teaspoon cumin seeds

2 heaped teaspoons coriander seeds

12 cardamom pods, bruised in a mortar and pestle to expose the seed

1 level teaspoon ground red chilli

1 level teaspoon ground turmeric

110g fresh root ginger, peeled and grated

1 level teaspoon ground cloves

350 ml malt vinegar

8 cloves garlic, peeled and crushed

2 heaped teaspoons sea salt

2 brown onions, peeled and finely chopped.

To sterilise jars, they should be washed, dried and heated in a moderate oven for 5 minutes.
You will also need a preserving pan or large wide saucepan.

My Mango Chutney

Begin this recipe a day ahead by preparing the mangoes. The easiest way to do this is to cut the two cheeks away from the stone with the skin on.  Segment the flesh of each cheek with a paring knife in a criss-cross fashion into bite size pieces.  Scoop out the flesh with a spoon.

Peel the skin off the remaining flesh on the stone and slice off the flesh.

Then sprinkle the sugar over the fruit in the bowl, turning it lightly to distribute the sugar evenly, cover and leave it in a cool place overnight (or a couple of hours if you are in a hurry)

This chutney really works best if the cumin, cloves and coriander  are freshly ground.  I have bought an electric spice grinder just for this purpose and the difference really is in the taste!  It explodes in your mouth.

Add the freshly ground spices, leaving the cardamom whole but slightly bruised, and add all the other ingredients.

Heat it until it begins to bubble and let it simmer for about 2 hours, stirring from time to time, until the mango becomes translucent and the liquid has almost evaporated, leaving behind a thick syrup.

You will need to do a bit more stirring from time to time at the end to prevent it catching.

After that remove the chutney from the heat, let it cool for 15 minutes then ladle it into warm sterilized jars. Seal whilst the chutney is still hot and label when cold. Best if left to mature for a few weeks, but you can eat it straight away.