Are some of your trees actually weeds?

[BradN]

The African tulip tree is toxic to native stingless bees and other insectsWhen you see a tree in a garden it's natural to assume that someone planted it there.

Sometimes, though, trees are invasive species that have spread by themselves and are damaging your local environment. One very common example in Queensland is the African tulip tree (Spathodea campanulata), which is toxic to native stingless bees.

Other times trees and large bushes are simply overgrown hedging plants, such as lilly pillies (Syzygium species) or orange jessamine (Murraya paniculata), that have haven't been trimmed for years – or even decades.

Pointy pink leaves give away an overgrown lilly pilly hedgeWalking around my neighbourhood I see people who can't see out of their windows because what started out as a low-level hedge or border beside the house has now grown taller than the house.

The good thing is that identifying a weed tree or overgrown hedging plant enables you to improve your garden by removing unwanted plants and replacing them with something more suitable – or just by getting an unruly old hedge back under control.

Overgrown Murraya hedges can block out windowsMany local councils and other organisations have websites that can help you identify invasive trees and other weeds.

Apps such as plant.id and the built-in plant-identification app in newer iPhones are also great resources (Tip: take clear photos of flowers and foliage wherever possible).

Do you have any suspicious trees in your garden? Post a photo and our knowledgeable members will try to identify them for you.

Brad

[MitchellMc]

It's surprising what you find out about plants in your own garden after doing some investigating @BradN. I didn't realise the large tree in my front yard was actually a White Cedar. They are pretty common and a Toxicity category 1 plant, that's about as poisonous as you can get. I only realised this after my little one decided to chew on some leaves, and me being a good dad thought I'd check to see just what it was. I found out what it was through Googling and Plant ID apps. Took me a good hour to deduce the identity as the reference images were a bit off. Headed straight to the emergency room as two berries can put an adult in a critical life-threatening situation, and the leaves carry the poison too. She was fine, but it scared her Mother half to death.

Mitchell

[BradN]

Oh wow, @MitchellMc. That must have been terrifying. It's pretty wild how many poisonous things are just lurking in plain sight. Did it make you suspicious of everything else in your garden?

I'd never seen that Queensland Government website you linked to, but their main page of toxic plants is an eye-opener. I reckon at least half of them are growing in my street, and plenty of them in my own garden. I'll have to have a proper read of it.

Have you noticed many invasive trees near you? Some of the biggest ones where I am on the Gold Coast are the African tulip tree and the Cocos or queen palm (Syagrus romanzoffiana), which grows absolutely everywhere and kills flying foxes. The council is constantly cutting them down.

[MitchellMc]

@Brad,

It did make me second guess every other tree, but instead of dealing with them, I've just taught my daughter not to eat plants. Fingers crossed she doesn't try it again.

Privet is a big issue near me, and it's surprising how quickly it grows. There is plenty of nearby bushlands, and the native birds and bats carry the seed far and wide. Just about every backyard near me has them growing. They are actually quite a nice tree and provide significant shade, but are horrendously invasive.

Mitchell

[TheHandySqirrel]

I think we need to shift how we manage and design our gardens and become knowledgeable about native vs non-native species.

There are so many beautiful Australian trees available, and the council lists (which @BradN mentioned) provide lists of which species are native to their area - this allows us to support local flora which in turn is beneficial for the local animals. And most of the time we can spend less time looking after the Australian plants as they're well adapted to the conditions.

Here's a suggestion: Why not mark plants "Australian native" on websites of nurseries and hardware stores (ahem, Bunnings!). That will make it much easier to for gardeners to make informed choices.

We had three Celtis trees at the back of our yard which were also fast-growing. I'm happy that they're gone and that I could add our native replacements to the NSW tree register.

[Jason]

Thanks for sharing @TheHandySqirrel. Let me tag @robchin as I'm sure he will be interested in your comments.

Jason

[robchin]

What an interesting discussion this is. As somebody who works in this space (for Bunnings) it's a discussion that is often had. I would note a couple of things: 

1) Not all exotic trees are weedy, in fact - the vast majority are not and not to be concerned about.

2) Not all native trees are good. Some in fact are quite invasive. 

3) Not all native trees are suitable for planting in urban gardens - for example they may grow too big, damage drains or paths/paving or drop limbs.

Couple of correspondents have noted that local councils have lists that locals can refer to. That's a great place to start. Most of these lists will include native and exotic plants though. 

So, it may not be a universally popular opinion, but you can have one or the other, or a combination of both. 

As an aside - many of the trees listed on the Bunnings website are called out as Native, but not all are. If you are unsure or need more help - ask your local greenlife expert in one of our stores or wherever you buy your plants. 

[BradN]

Hi @robchin. Those are all very important points.

It might seem a bit odd at first to think of a native plant as being invasive, but as you point out they certainly can be once they get out of their natural range.

The umbrella tree (Schefflera actinophylla) is native to tropical north Queensland but it's quite a problem where I am in here south-east Queensland. It outcompetes local native trees and upsets the balance of native flora and fauna.

There's nothing quite like knowing exactly what you have in your yard so that you can make an informed decision about whether to keep it or replace it with something else. Apps such as plant.id are fantastic for that.

Brad