Wonderful Weeds

Wonderful Weedsby Spencer Shaw – Brush Turkey Enterprises
Our phobia of weeds is something quite extraordinary. If visitors from another planet were to land on our door step tomorrow and study the average garden I’m sure the questions would run something like this: a) Why do you waste so much time cultivating plants that are so inbred that they can survive only with your assistance? b) Why are plants native to anywhere else on the planet other than where you actually live so attractive to you? And finally c) Why do we spend so much time at war with plants that are very successful at proliferating in spite of our attempts to wipe them out.I’ve mentioned in previous articles the possible benefits of the tree weeds such as Camphor to our local wildlife, but today I’d like to bring to your attention another much maligned group of weeds that in reality have very few down sides and offer great benefits – they are the “Annual Herbs” or “Herbaceous Weeds”  and I’m not talking parsley here! This brings us back to question, “Why do we spend so much time at war with plants that are very successful at proliferating in spite of our attempts to wipe them out?” As a profesional and recreational ( just can’t help myself! ) native vegetation worker  my particular answer would run something along the lines of, “to protect the diversity of our native flora and fauna and their ongoing ability to reproduce themselves and the ecologies they are part of, we must control the exotic plants that threaten their survival ”. However are all weeds a threat?Cobbler’s pegs, Fleabane, Inkweed, Thickhead, Cats Tongue, Thistles, Milkweed, Blue Top and Amaranth are some names you may be familiar with of a group that we classify as annual herbs or herbaceous weeds. They are in general, short lived non-woody plants that produce large numbers of seeds, are mainly wind dispersed but also in some cases, dispersed by small birds. All the plants listed above are exotic and thrive in disturbed ground – they just love revegetation and bush regeneration sites. At best we are dismissive of them and at worst we hate them. However, how valid is the case against them? In the case of rainforest restoration, I’m going to offer myself as devil’s advocate (as usual) and argue the benefits of these weeds, but I’ll try and also argue against myself to remain somewhat impartial and either end up schizophrenic, or at least run a 50/50 chance of being correct. Often in the early phases of revegetation sites herbaceous weeds grow exceedingly well. We create a situation that is perfect for them. The availability of nutrients in the soil rises as grasses are killed off, fertilisers are added to improve tubestock growth and the very act of planting cultivates the soil and releases latent fertility within the soil. Herbaceous weeds (exotic or native) are the true pioneer plants, in that they are the first step in the floral succession to colonise bare ground. Also these plants are some of the main plants you will spend the next 3 – 5 years waging war against if you follow the conventional wisdom of revegetating rainforest in our local area and have the inbuilt weed-phobia that most of us are born with.Are these plants actually detrimental to the growth of planted stock? In most cases I would offer a definitive, No. They are often genuinely beneficial, particularly the lush herbs such as milk thistle, fleabane, thistles, thickhead and inkweed. These guys improve soil quality, act as living mulch, provide frost protection and create a humid microclimate that our planted stock can often thrive in. The main reason most of these weeds are cleared from revegetation sites is cosmetic. In clearing these weeds it could be argued that we over-use herbicides and brushcutters and that this in itself causes unnecessary damage to our planted stock. Now I’m not suggesting for a moment that we let our revegetation patches become a mass of weeds and say “bye, bye its time to look after yourself now” to our tubestock as we plant them. On the down side herbaceous weeds can hide a lot of nasties, such as Glycine, Silver Leaf Desmodium and worst of all ……. the running grasses such as Kikuyu and Couch! All these plants are real and serious threats to the ongoing health of a revegetation site and need controlling and so will the herbaceous weeds that hide them. Also the herbaceous weeds can make it very hard to even find, let alone check on your planted tubestock, but staking can over come this.As with all weeds we should look at this group of plants and start asking questions of ourselves about how we manage them. What are the positives and negatives? Can we improve growth of our plantings by selective management? Can we use them as a resource, rather than seeing them purely in terms of being a pest? Perhaps we need to be tapping into their ability to thrive in spite of what we throw at them.