Weeds: Spray Free Solutions

The very best way to weed is smothering, also called mulching. It’s an oldie, but a goodie. No straining or digging required, it’s as easy as an armload of whatever mulch I have lying around dumped thickly a top the weeds. Feeds the hungry microbes as well – two birds, one stone. Put cardboard beneath the mulch for a bit of extra. 

Sadly not all weeds can be smothered. These weeds I call pernicious (and other things not suitable for this post). Though you can minimise them, you may never eliminate them. Either way it takes time, and for peace of mind it helps greatly to relate to them as an ongoing thing. 

My spray free strategies are:

Change your mindset! Weeds are mineral rich powerhouses – awesome to add to composts, they provide habitat and food for bees and beneficial insects and above all, are healing your soil by bringing to it exactly what it needs. Relax about your weeds! Keep improving your soil and slowly the weeds will evolve and the tricky ones will ebb away.

Improve your soil: Weeds proliferate in certain conditions – change the conditions and you’ll loosen the weeds grip on it. Mulch, homemade compost and deep rooting shrubs/ trees are the foundation of your soils health. Dense planting leaves no room for weeds and if you plant a lovely mix of deep and shallow rooting plants, you’ll further improve the soil – heaps of ideas here.

Interplant: Many weedy problems can be overcome with subterfuge. Rather than the huge effort of elimination followed by the constant work of keeping the weed back, sneak up on it by interplanting the weedy area with taller shrubs or trees and competitive groundcovers. When a weed is no longer dominant, rather interspersed amongst other plants that you love, you’ll stop worrying about it so much. You may need a few stabs at it to work out which plants will outcompete your weed — but it’s a far easier, gentler approach than spraying off an area and laying it bare open to a speedy colonisation of yet more weeds.

Little and often: surely the answer for everything! Making weeding a little and often event keeps weeds small. This makes a massive difference in catching weeds before they set seed – one years seeding = seven years weeding!

Use animals: goats for thistle and blackberry, chickens for clearing vegie beds and beneath berries, and pig for convuluvlulus. Create animal runs along fence lines where incoming weeds arrive from your lovely neighbours.

A Rogues Gallery

• Buttercup, inkweed and dock

Cut seedheads off dock and inkweed during the growing season – I whizz round the paddocks with the weed eater. A tractor mow would be more appropriate were we on a larger block. This chop and drop method benefits the soil by returning the tops as a bit of soil food. Our core tenat remember – improve the soil and change the conditions!

On small sections grub or dig out the day after it’s rained – trust me its easier this way. Over time, the improvements in your soil will soften your soil and you’ll pull docks out with ease.

Gypsum or woodash or lime lightly dusted in spring will slowly but surely turn this ship around.

• Convulvulus, Ivy + Jasmine

Vines are tough customers. At my place, nourished in our claybase soil – convulvulus winds for miles and miles, smothering all in it’s path. We have tried every trick in the book.

On bare ground lay clear plastic over top the patch and use planks to seal the edges. In the heat the new growth will shoot away but it’ll quickly fry and die. When no greenery remains, go over the area with a garden fork and get up as much root as you can. Burn it all up and add back into your compost. If you cannot burn it, seal it in a black plastic bag until it has rotted. Plant the cleared space up straight away. As new bits appear, patiently follow the root back to source and whip it out. It’ll become easier and easier as the soil improves.

Pigs love convulvulus root and we use Nellie our kunekune, to root up those protein rich roots over winter along our south and east fencelines. This is simply a temporary fix that holds the tide back at our fenceline – every little broken bit of vine left in ground will re strike. We put her in this run every year and hold it at bay in this way.

Where convulvulus winds through existing plants – well, we’ve got a problem Houston. The roots twist through existing roots and set up a home. This is what we have along our northern line and to date it has me beat. After years of removing miles and miles of vining tops manually, I spread my search into chemical solutions. Knowing I would never spray, I wasn’t sure there’d be an answer here, but there was. I found cutnpaste, a roll on glyphosate developed by kiwi park ranger Andy Spence. Until there is another option, this is the only thing saving my orchard from drowning in vine.

Every year in December we dab the ends of the new growth and every year less arrives. None of the flaxes or corokias or manukas that share the space have ever so much as turned up a leaf. The guys at cutnpaste are working on a glyphosate free alternative, which I will jump on as soon as it is available. Meantime, this one works brilliantly. And I’m happy to save my fruit trees without nasty spray drift. There’s a huge difference between spraying glyphosate and rolling it on. 

• Blackberry

Like all weed infestations, your management depends on how big your land and serious the problem. On an acre or less, I’d happily hand grub the blackberry, then plant trees/ shrubs and perennials reinvesting the land with a healthy soil biome and thus making it less amenable to blackberry. Bring the soil life with mulch, biological sprays and mixed plantings. Blackberry is an open ground, edge weed so the more trees you plant, the less it’ll flourish.

On more than a few acres of blackberry filled land either clear it out with a digger then use goats or cut’n’paste on the regrowth. You may need a one off taming spray to be able to get to the ground to replant the area. 

Consider leaving some for your own fruit supply.

• Tradescantia (wandering willie)

This little weed is serious in bush because it puts a halt to regeneration, flourishing in the light gap made when a tree dies and stopping new natives coming up.

Chickens love tradescantia. They’ll clean the area up for you in the best way possible. If you are chicken-less rake it all up, hunting out every last scrap. Stuff it into a black plastic bag and leave it down the back of the garden somewhere for a year or more. Turned to sludge, it’s a nutritious addition to your compost.

Alternatively I’ve had good success with laying clear plastic over the infestation and letting the sun fry it.

Dense planting including vigorous, evergreen, perennial groundcovers will outcompete tradescantia if you eradicate it first. While new plantings establish, keep on top of new bits that come through.

• Runner grasses

Kikuyu spreads out via runners below and above ground while couch (or twitch) runs below the topsoil. They are both really determined grasses.

In open areas, knock the grass back by laying plastic on top for summer and autumn — or until it’s died off, then lay cardboard thickly, pile the mulch on and plant a guild of soil enriching equally determined plants – soft, gentle annuals will not do it! Fast growing nitrogen fixing trees teamed up with vigorous tap roots and tenacious groundcovers work a treat. Don’t turn your back though.

If these grasses are in your vegie patch, keep on keepin’ on with weeding them out, at the same time adding loads of compost and mulch to loosen their grip on the soil. The roots that peg them down will get further and further apart, making them easier to manage in time. I’ve suggested ‘little and often’ for weeding generally but it really is the key here, and a long term view.

Where you have a sizable tract of land to manage and kikuyu is aggressively taking over existing plantings, consider using Cut’n’Paste until plantings establish. Ever after keep it in check with mowing, grazing, mulching or a combination of all three.

• Oxalis

High on your list as a pernicious weed, and I understand it is annoying! But it’s so small and shallow rooted and self-contained that it barely competes for nutrients. My preference is to outcompete it with perennials and choose another area for your vegie patch. Oxalis thrives on disturbance so its going to keep on keeping on in an annual garden. 

If your mental health relies on its removal then you are in for the long haul. Prepare yourself. Baking soda spray at the rate of 1tablespoon per 500ml water sprayed under the sun at regular intervals to eventually wear the bulbs out.

Smothering works well too. I’d baking soda spray in a determined way until the foliage has completely died off, then lay cardboard and deep mulch on top and plant into that to avoiding disturbing those tiny bulbs.

If you have chickens then rejoice – they love oxalis as much as you don’t.

• Driveway weeds

Salt. Buy a 20kg bag of fine Ag salt from Farmlands. Sprinkle on top of weeds, especially good just before a rain.

Edible weeds

Chickweed, dandelion, nettle, mallow, puha, fathen, and wild onions are all good for dinner. Try them out – you’ll wonder why you bother gardening! Do identify correctly. Check out Simply Living by Gwen Skinner or A Foragers Treasury by Johanna Knox.

A One off taming spray

In all my years consulting I’ve only twice recommended spraying. At all costs, we try everything to avoid it, but sometimes no other options work because of steep ground, lack of access or the sheer intensity of the weed. In these cases consider spray as a tool to clear difficult land but never for ongoing management. Thoughtful design, dense plantings, animals, mulch, minerals, biological sprays and a commitment to being spray free will make it so.

Spraying is insidious. The particles and vapour spread further than the little bit you just sprayed, and hang round longer too. If spray was dyed, I believe no one would use it.

“95% – 98% of applied -icides miss their target, reaching nearby people and wildlife, waterways, soil and air” Source: Miller GT (2004), Sustaining the Earth, 6th edition. Thompson Learning, Inc.