Weeding

Sunday, 17 May 2015

Choice weeds in my garden

My current garden was chock-a-block with all the choice weeds when we first arrived here 21 years ago: oxalis, soursob, wandering jew, onion weed, Madeira vine and asparagus fern, and it has taken years to get on top of them. Other less pernicious, but still persistent, weeds have also plagued me: chickweed, basket weed and miscellaneous grassy-looking weeds.

Basket weed in my garden

Innumerable hours have been devoted to weeding down through the years; however, these days it is less onerous - partly because I have at last embraced the use of mulching as a way of suppressing many weeds. Having a fairly large garden, it was always rather daunting to contemplate how many bales of cane mulch (my preferred material) would be needed to create a proper layer, so I did it in stages last spring, buying just two bales at a time and spreading these before buying the next two. The results have been pretty good overall, in terms of weed control (some weeds still pop up but not anything like what I used to get), and I plan to do it all over again this coming spring.

Browallia americana self-seeds in my garden

The downside of mulching is that there is the prospect of losing self-sown seedlings in the garden. I have a few plants (no doubt regarded as weeds by many other gardeners) that I love to see spread themselves around my garden to create a slightly wild look and to become repeated motifs to tie the garden together. The main ones are annuals: the spring-flowering Orlaya grandiflora (like a refined Queen Anne's lace), white honesty, annual Primula malacoides and Viola tricolor; and summer-flowering Amaranthus caudatus (which is almost like a shrub in its dimensions and flowers for six months) and Browallia americana. Some perennials also self-seed in my garden and I am always on the lookout for them: Linaria purpurea, with dainty spires of pink, purple or white flowers, one of the few English-y cottage plants I can grow; hellebores; Thalictrum delavayi, with its maidenhair fern-like foliage and clustered lilac flowers in spring; Dahlia hybrids; species Geranium; and a number of Salvia.

Salvia Indigo Spires (rear) with pink Garvinea at front

In fact, many of the lovely Salvia cultivars we have in our gardens today were found as chance seedlings in someone's garden where one specimen has crossed with another - for example, Salvia 'Indigo Spires' (pictured at left), 'Wendy's Wish', 'Waverley' and many of the greggii and microphylla cultivars. Nothing like that has ever happened to me but to allow all my desired self-seeders to continue to appear in my garden, I left gaps in my mulching - so I still do have some weeding to do! The prospect of finding worthwhile seedlings in the garden makes the weeding more fun!

Seedling of Primula malacoides - a desired weed!

I have never really used chemical weed-killers in my garden, as I am too fearful of their effects on human and environmental health, so most of my weeding is done by hand. My main tools are an old long-bladed kitchen knife and a very sturdy stainless steel trowel that is cast as one piece - ie no separate handle that can bend or break off just as I am about to dislodge a large clump of oxalis, as has happened to all previous trowels! In my younger days, hand-weeding was simply a dreaded chore, as I would much rather have been doing exciting things like planning garden beds or buying plants. For some reason, I find the task somehow soothing these days. The need to concentrate on the job produces an almost meditative state of mind, and there is such a feeling of triumph when I am able to get the bulb of a truly horrid weed such as oxalis up! When the soil is damp (as it still is at the moment after the recent heavy rain), I am usually more successful with my weeding. I put all my weeds into our green Otto bins, though I know some people make a sort of 'weed tea' by putting them into an old plastic garbage bin, covering them with water and leaving it for a few weeks until a nutritious liquid has formed and the weeds are dead: the plant material is then put into a compost bin and the liquid diluted to the colour of weak tea and used as a fertiliser. I probably wouldn't risk doing this with bulbous weeds.

This oxalis in paving can be tackled with boiling water

For weeds in paving, which are difficult to get up by hand, I have been experimenting with using boiling water poured over them, with reasonable success. There is a certain satisfaction in seeing the weed wilt and crumple under the onslaught of the boiling water. I have heard of vinegar mixed with a bit of liquid detergent and water being a useful weedkiller spray, as long as it is kept away from garden plants, and I also intend to try this method.

Looking for desired seedlings amongst the weeds makes me examine my garden closely, and keeps me in contact with the day-to-day changes that make gardening so rewarding. I don't ever expect to get on top of them completely, however!

Reader Comments

  • By Maureen 2118 Monday, 18 May 2015

    Good old knife trick!!! Over the years I have lost a couple of black handled ones having jammed then blade down somewhere but now have a long wide blade bone handled dinner knife from op shop which stands out more when planted somewhere! Great tool with many garden uses indeed. Yesterday was a fab day for deweeding. Cheers Great idea to use a knife with a light-coloured handle. I have my mother"s old gardening knife, which I think was from what was originally her best cutlery set! Deirdre

  • By Janelle 2132 Monday, 18 May 2015

    We too got into the weeding yesterday, but feel we are fighting a losing battle against onion weed in one of our large flower beds. Any suggestions as to how we can get rid of this demon? We have a thick covering of cypress mulch but the onion weed keeps popping through :( See comment from Norm below - I have never used the vegie oil but I will be giving it a go. I have also read that if you keep cutting all the foliage off the onion weed it will eventually weaken the bulbs. Have not tried that method myself though. Deirdre

  • By Norm 2046 Monday, 18 May 2015

    To eradicate onion weed, pour some vegetable oil into the crown. This will kill the plant by turning the bulbs mushy. Repeat a few times with the smaller plants from the side bulbs that "escape" this first treatment, but with patience, it does work! Had never heard of this method, Norm - thanks so much for telling us about it. Will try it! Deirdre

  • By margaret 2122 Monday, 18 May 2015

    Lucerne was my preferred mulch, until it became too expensive and I have used sugar cane for years. Self-sown plants such as primula, zinnia, cornflowers, orlaya, poppies, cane begonias and coleus, to name a few, always appear. The trick is not to spread the mulch too thickly. Some weeds do appear, but are easily removed. My favourite tool is a dibbler, made by my brother in law, as it can access the smallest space. Boiling water on weeds in cracks, and vinegar, used on the lawn, work well. Reassuring to know that it is possible to mulch and still have self-seedlings! Will definitely try the vinegar idea. Deirdre

  • By Sue T. 2566 Monday, 18 May 2015

    In my experience Kikuyu merely lurks maliciously under the mulch while gathering strength for its next onslaught. Sounds diabolical - it may need newspaper over the top? I have also heard of putting plastic down to solarise weeds through the heat of the sun. Have not done it myself. Deirdre

  • By Susan 2430 Monday, 18 May 2015

    When I gardened in Canberra, pratia was a desirable plant but here on the mid north coast it is everywhere and is such as untidy curse. I think it came in on some mulch. it has a network of thready white roots matting through other plants" roots which make it hard to remove. Any ideas? Sounds a tricky one - hope someone has some ideas on that one! Deirdre

  • By Clare 3123 Monday, 18 May 2015

    40g salt plus 90ml vinegar made up to 1litre with warm water in a spray bottle works a treat on creeping oxalis in stonework. I have heard salt is good on weeds in paving. Will try your method. Deirdre

  • By Marion 2068 Monday, 18 May 2015

    For weeds in pavers I was advised to use salt - on a dry sunny day. A few days later and the weeds are brown and most often can just be swept or brushed up. Sounds effective! Thanks for the tip. Deirdre

  • By Janice 2067 Monday, 18 May 2015

    The late Allan Seale"s advice to a desperate gardener who questioned him about the eradication of onion weed was "to move"!!! Can understand that sentiment. It is so persistent! However, I am going to give the vegie oil idea a go. Deirdre

  • By Lynne 2479 Monday, 18 May 2015

    Wandering Jew is the bane of my life, and camphor laurel seedlings. I have spread some cheap weed mat on some open areas and mulched on top of the weed mat. So far, so good. It does feel so good when I finish a good day"s weeding, followed by a cup of tea and a biscuit. I think the barrier idea under mulch is good for very persistent weeds. I agree the cuppa at the end of weeding is wonderful! Deirdre

  • By Karin 2106 Monday, 18 May 2015

    In the first photo of your Weeding blog there is a trailing weed that has 5 leaflets and grows upwards and then sprawls all over the tops of other plants - it isn"t the Madeira Vine with the large, roundish, juicy leaves - it looks more like a weak version of a Virginia Creeper, but totally green and all over Pittwater - do you know it"s name? I have taken it to numerous nurseries and searched the net for it, but to no avail? I have a lot of it! I think it is a Cardiospermum, often called balloon plant or ballon vine, because the seed pods are like little balloons. I try to pull it up when I see it as I do not want it to go to seed. It is very persistent and quite hard to dig up as it tends to break off just as I think I have it. Try googling this name and see if it is what you are thinking of. Another possibility is that it is wild passionfruit -- the rootstock from grafted passionfruit that have suckered and spread by seed -- a pretty bad weed. Deirdre

  • By Gillian 2073 Monday, 18 May 2015

    The weed I have never been able to control in this garden is Alstromeria psitticana (sp?) It has resisted everything I have ever tried to eradicate it with. I once spent days sifting the soil to remove tubers and still it came back. The council sprayed it with some truly noxious spray (where it lurks in the bush behind us) and triffid like it was back after the first decent rains! I might try the veggie oil trick next! Thanks. I forgot to mention I have this horrid one. It is incredibly robust. I too will try the vegie oil on my (large) patch of it. Deirdre

  • By Janna 0 Monday, 18 May 2015

    I love weeding, too! At least the annual weeds. Such a sense of satisfaction when it"s done and as you say, you really get to know every inch of your garden doing it. I"m jealous of your clay soil though - I was out watering my sandy soil yesterday. All those new plants I have put in this autumn! It is surprising how the soil is drying out even after the many inches of rain we had. There is such a sense of achievement after a session of weeding! Deirdre

  • By Diane 3788 Monday, 18 May 2015

    I tried using vegetable oil on onion weed as a trial where it was coming up amongst daffodils as I had read it was a good method. An hour or so later I was wondering where my 2 cocker spaniels had disappeared to and yes they were having a lovely time licking the oil off the onion weed, so no it didnt work for me..... Did chuckle at the thought of the dogs lapping up the oil. I am going to try the method to see how it goes on the onion weed in my garden, though the cat may be attracted to it! Deirdre

  • By Bren 2540 Monday, 18 May 2015

    I think I have been spreading weeds throughout my garden with the compost I have been making, mainly through seeds. Does this mean that I have not let the compost "process" enough before using it? To really kill weed seeds, I think compost needs to reach quite high temperatures. This entails having to turn your heap quite a lot. I never seem to manage to do this so my compost is more of a cold heap that takes a while to break down. I would not put weeds into my heap because of this. I put them all into the green Otto bin. You could try the weed tea method - the soaking seems to kill off all the seeds - I am not sure about bulbous weeds, though. Deirdre

  • By Suzanne 2073 Monday, 18 May 2015

    I confess to being a "weedaholic". My 1/2 acre garden started as a garden of weeds. We smothered an area with old carpet and underfelt then a thick layer of bark chips and attacked any weeds that came through. Then moved onto the next area but always going back to the first to clear any weeds. It did work and now I still remove a weed before doing any other garden chore. I never compost weeds and now love watching all the annuals resurface annually. I keep bought plants in pots before planting. That method sounds very effective, Suzanne. I also admire your approach of removing weeds before doing any other garden job. Deirdre

  • By Maureen 2118 Tuesday, 19 May 2015

    What a great helpful response to your weeding blog Deirdre which proves we are not alone in our weeding battle. Thanks to all who contributed.

  • By Lesa 2445 Wednesday, 20 May 2015

    An old bread knife with shortened blade is excellent. Dip the end of the handle in red or white paint to help you find it in the garden. A great tip, Lesa. Deirdre

  • By Karin 2106 Monday, 25 May 2015

    Thanks Deirdre! I googled Cardiospermum "horribilis" - it looks identical except for the balloon-like seed pods and it"s not the Passionfruit sucker either - if I can ever find someone to identify it, I"ll send you it"s name. I"m staring at one as I type which has rambled up through a 5m Leptospermum, but I pulled it"s roots out yesterday and now it"s looking rather droopy on the top of the shrub :) Karin

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