Gum Trees - and their root systems

[Mondo Grass]

Hi Folks,

I am considering planting some gum trees in my front yard. I will have quite a bit of convincing to do with my wife, as they caused some issues at her parents place in Lithgow NSW. Their root systems apparently went down the drains, etc and they had to be removed... Am I right to say that if they are planted too close to the house they can cause issues with the foundations? We are on stumps.

I was thinking of planting some with the beautiful white bark (I think they're called lemon scented....") They would be approx 7 - 10 metres from the house so I'm thinking they would be OK. They would be fairly close to a footpath.

Why I like them:

- Fast growers (we are desperate for shade on that side of the house)
- Nice trunk
- I like natives
- Great for the birds?

Appreciate some advice and comments, thanks in advance.

Cheers

Richard

[sara]

The only experience I had with a gum (sugar gum) was in my last house and that it was a) a nightmare for the sewage system - cost thousands to keep out of the system and b) it was as dangerous as hell because of the falling branches - one day I watched it drop a 10 metre branch not a metre away from two women and a pram ...

I won't have one again, but I am sure that some are safer than others.

[Mondo Grass]

Thanks,

I was speaking with a guy who is part of the team that looks after Werribee Zoo the other day - he also mentioned them being notorious for dropping limbs.

Cheers

Richard

[Longy]

Hey Mondo, lemon scented gums are notorious limb droppers and are a huge tree. Not ideal for a close to the house planting or anywhere else on a suburban block IMHO.
I'd say there are more negatives than positives re gums near houses. Apart from the rootsystem, the amount of leaf drop into gutters is quite staggering. Also there is the fire factor. They can be explosive in a fire.
I'd reconsider the gums and look at something which is less of a potential problem.

[sara]

Ah yes, I'd fogotten the gum leaves in the gutter problem - they drop all year round, too, which means that you are constantly cleaning (or paying someone to clean) your gutters. I was not sorry to move and leave the nightmare behind me.

[froglover]

I have to say I just love our huge gum trees that were already on the block when we bought it - we have about 9 gums and one is right near the house and it is a huge graceful tree that has had a pair of Kookaburras living in it for the past 8-10 years. A couple of horticulturists vouch for its solidity, but it still drops the odd big branch!

[Ann]

Aret the smaller eucalypt as bad. Town and city councils use many of the smaller gums as street trees so I do not think they can have many problems. I have planted a lot of 3m hakeas, OK they are native to here, as well as a few othersE ficifolia or Corymbias are abot 3m and flower well. The new grafted ones are a mass of colout when very small.

[Chris C]

Hi Richard,

I share your enthusiasm for lemon scented gums, they really are a lovely tree. We have a couple here. I once sent a leaf to a friend who was overseas, with the instructions to crush it, hold it under the nose, and think of Australia. Apparently they nearly jumped on the next plane home...

However, I'd share everybody's reservations about them. They eventually get massive and then can be difficult and expensive to remove from small blocks. The roots and leaves can be a problem, and they can be a real fire risk, depending on where you are.

Many of our trees here can be limb droppers - either through wind or due to a process sometimes known as "hydraulicking". This can cause trees to drop limbs on a perfectly calm day. If I remember rightly, it works something like this. On a hot Australian day a big tree can be sucking up moisture at a pretty hefty rate. If the leaves sudddenly sense a temperature change (even a suddenly clouding over can reputedly do the trick) they can shut off the flow very rapidly. In extreme cases the stress of this can cause a branch to break - a bit like shutting your hose off quickly and having it pop off at the tap end.

Fire can be a big consideration too, although it depends where you live of course. When planning our tree balance round the house I studied material about the Ash Wednesday fires, and also the recent Canberra fires where several suburban houses were lost. Apparently the Canberra houses weren't lost through direct attack from the main fire front. They fell foul of airborne burning material that fell on them and caused mostly smallish fires that then developed into big ones.

Having a tree near a house is great for shade and wildife, but it simply provides a wick to light your house with if you have a fire. Friends of ours nearly lost their house in that way. Trees near the house caught fire, the burning leaves feel onto the roof and onto the air conditioner, which then collapsed into the roof, setting that on fire.

If you think you can cope with the side effects (as with anything you grow) then they shouldn't be a reason not to go ahead. I guess it's just good to know what the possible negatives are, and be forewarned.

Chris

[sara]

In Israel, Australian gums are known as Widow-makers, for their suddenly falling limbs, and every year in Australia at least one boy scout troop is struck when they pitch a tent under gums (or a car). Never ever park a car under a gum tree. Or pitch a tent there.

Christ is right - the most dangerous time for gums is when there is a sudden cool change after a heat wave.

Ash Wednesday fires - I will never forget the sight (I lived in the Adelaide Hills then, where many people died) of watching massive balls (twenty feet across at least) of combustible material, mainly gum debris, leaping hundreds of feet into the air and then being blown a quarter of a mile away, there to explode and set a new area on fire - it remains to this day the most terrifying and malevolent sight I have ever witnessed - the power of the day, and of the fire, which had a life all its own, was extraordinary.

You know, I think that's when I conceived my great love of cottage gardens as opposed to native gardens - I watched the Adelaide Hills explode - all the eucalypt feeding the inferno, and all I ever wanted around me after that was fresh green stuff.

I recall seeing on tv recently a programme of a couple who'd bult the most desirably environmentally friendly house on stilts in the middle of the bush. They were terribly proud and not a lttle smug about it. I sat there with my mouth open in disbelief as I watched the wife rake great drifts of gum leaves under the house in order to create a natural environment. Neither of those people, nor their architect, have ever lived through an Australian bushfire, obviously.

[Longy]

Hey Mondo, you said you needed some quick growing shade for the front of your yard. Your profile doesn't say where in Oz you come from but if you supply that information it would be possible to suggest some suitable shade plants. Climate, soil type and drainage are the main factors i guess.

[Mondo Grass]

Ok, thanks so much for the replies - I think I'll stay clear of gums.

My wife loves deciduous trees (elms, etc) however they take ages to grow as far as I am aware....

I live in Ringwood North, Victoria, someone on this forum did suggest going about a landscaping plan some time ago - which is a good idea, however I just haven't had the money to pay someone to do it (or the time to try it myself).

I know some large trees are the start to our shade issue and want to plant them asap. I would like to live in this property for another 5 years or so, then rent it out and move somewhere else with a bigger back yard and living space...so no matter what the future holds, the shade issue needs to be resolved. I am dreading summer again - we have so many north facing windows it's just ridiculous.

Tree suggestions (fast growers) would be well appreciated.

Cheers

Richard

[Mondo Grass]

Hey again,

Just did a little research on the Crape Myrtle (another tree I am quite fond of)

They apparently come in many varieties, so I am thinking I might be able to source some that are suitable for my shading purposes....thoughts?

Also, thought I'd add, I do already have a magnolia planted in my front yard, it is about a metre tall and hasn't really grown much in the four or so years since we've been here. It is however looking healthier now - so I assume it's root systems are becoming more established.

Cheers

Richard

[Bertha]

I sat there with my mouth open in disbelief as I watched the wife rake great drifts of gum leaves under the house in order to create a natural environment.

Which makes one wonder if they were sane at all...

I, too, have witnessed bushfires in dismay...I am more interested in "fire retardant" plants around the house. When people say " oh the lawn is a waste of space, turn it into native area" I think "Nup, my lawn is my insurance policy against fire"...MInd you the area around our 20 acres is relatively cleared, having been farmed (ploughed, seeded and harvested) for many years...but as EllenGray says, bushfires take on a life of their own and these fireballs can jump firebreaks like you wouldn't believe....

How does one create a "natural environment" with gumleaf debris under the house??[/quote]

[Ann]

There are some fast growing but not necessarily huge exotic trees which can be planted safely near the house but can't think of the names right now . The bush opposite me went up three years ago and is still recovering very slowly.

[cordelia]

Mondo grass, for really instant shade a powlonia is the go. They will give fairly decent shade in 3 years. They can get fairly big, but ok for a reasonable suburban block. If too big you can just cut out the central trunk above the lowest branches and start from there. They are really pretty in flower, too...huge racemes of foxglove-like flowers which have an exotic perfume. They are deciduous. They can get borer eventually but the wood is light and easy to manage. You might think of it as a 10yr solution while other slower growers get going.

Silk trees are fast and lovely, tho susceptible to borer. If you don't mind using it you can inject something annually to protect them, I have heard.


Acacia fimbriata is a quick-growing shade tree. Apricots will take longer but can be pruned into a lovely canopy.

What I would do over the northern windows is have a pergola-ish/ canopy built, or extend the eaves. Or buy a very sturdy rose arbour, or make one with weldmesh. Or it can be as simple as a few sturdy supports with wire strung between. Then grow grapes or a banksia rose or other deciduous climber. Wisteria would grow quickly and be beautiful, but would need care to keep it under control...probably very unwise if renting out. It can climb into roofs and pull of gutters etc...though you can control it perfectly well if you have a serious check and prune 3 times a year, and don't put it near drains.

And add matchstick blinds hung from the eaves, and cooling short bushes or even climbing beans in front of the windows.
If the house is brick, a virginia creeper on the western and northern walls can make a huge difference to the inside temp, as it gives complete shade about 10cm awayfrom the wall and reduces the heat absorbed by the brick.

I think many of the gums would be fine, but they don't actually give very dense or cool shade. Many gums are quite disinclined to drop branches suddenly, and there is a wide variety of fire danger amongst natives. NSW bushfire brigade, I think, published a study of the relative fire protection/dangers of various plants.