When most people think of weeding the garden, they probably think about kneeling down and digging or pulling out the grass and the various seedlings that have popped up in unwanted places between the plants they want to keep. The most useful working definition of a weed is a plant out of place. And it is worth removing them, as they rob nutrients and water from our crops, making them slower growing. Weeds can act as a harbour for pests and diseases, too.
But take a moment to look up, once in a while, and be aware that weeds are not just little plants to be pulled out. Most weeds are successful because they require little help in spreading themselves to new locations, and establishing themselves once they have a foothold. A walk down any suburban street will reveal gardens full of weeds, some of them quite large. In rental properties, it’s often referred to as an established garden, and while the description is technically correct, just because a garden is full of large plants does not mean anyone planned it that way.
Bear in mind, if a tree is capable of growing in a particular location, with no real care or maintenance, chances are something useful could take its place and be productive. Sure, in rental properties it may not be so easy, but it’s good to familiarise ourselves with what plants are weeds. Chances are, if the garden is full of weeds, nobody is really taking much notice, and you could remove and replace them without anyone batting an eyelid.
The photos here are all from the same property in Melbourne’s Northern suburbs. The three plants shown are among the most common woody weeds, but obviously they are not the only undesirables. Cotoneaster (pronounced Kuh-toe-knee-astuh) is a freely hybridising exotic species that is spread by birds, who feast on the bright red berries. Some varieties are grown for ornamental reasons, and the plants are attractive, but they are most definitely out of place, and can harbour pests and diseases of related plants, like Apples (Malus domestica) for example. It should also be pointed out that if one of these is surviving, an Apple tree would also have no trouble. Unlike the dense evergreen Cotoneaster, deciduous fruit trees will let in light in the winter, and provide shade in summer, so other plants can be grown beneath.
The Mirror Bush (Coprosma repens) is another common weed, which many people leave alone for its shiny foliage, and quick growth. Originally from across the Tasman, this New Zealander has made itself at home in Australian conditions, and is highly invasive of native vegetation on pretty much any soil type. It seeds prolifically, and even after removal, seedlings may continue to appear for years. Again, it could easily be replaced with something useful, deciduous plants having the advantages mentioned earlier, but there are evergreen alternatives, like Citrusfruits, which would be a perfect replacement.
The final rogue in the gallery today is a local. Sweet Pittosporum (Pittosporum undulatum) is native to the wet rainforests of Gippsland, but has broken fee and can now be found in gardens and disturbed locations all over the country. Again, this is spread by birds, and can grow into quite a large tree, relatively quickly. There is one in my mum’s garden I have been trying to get her to remove for years, though it does grant some privacy from the neighbours. It will invade bushland, displacing local species, and in urban settings can make quite a mess with its sticky fruits dropping on the ground.
These three plants, and many like them, are simply overgrown weeds. They take up valuable garden space, produce little of value, and are effectively markers showing where something you actually want could be growing. The chances anyone planted them on purpose are virtually zero, no matter how established they appear, and if that is the case, get rid of them and put in something good instead. The easiest way to get rid of a large tree is cut the top off through the main trunk, then paint the stump with undiluted glyphosate, the safest weed killer there is. It will be absorbed and kill the roots, so the tree won’t sprout back. Keep an eye out for further seedlings, though, as there will be a seed bank in the soil, waiting for the warmth and light you let in.
As for replacement trees, you can pick up bare rooted trees for $15 to $30 in the right season, which we are approaching. But if you want to curb your spending, there’s no reason you can’t grow things from seed. Remember that a grafted tree of a named variety from a nursery will fruit a year or so after planting, while a seedling may take five or more years to produce anything. Of course, whatever it may produce will be slightly different to anything you’re used to, but you do get to name the variety if it’s any good!
The Garden Doctor 