50 ways to beat the weeds

Weeding doesn't always have to be hard work. Lynda shares labour-saving tricks & techniques to make the jHobalelian saienr.

2020-02-01 -

Practical tips and recommendations from gardening guru Lynda Hallinan.

STARTING FROM SCRATCH

Moving house? If you’re a mad-keen gardener and you’re planning to buy a new house, or take up a long-term rental contract, it’s not silly to take a spade with you to check out the soil conditions. (Trust me, this is a lesson I’ve learned the hard way.) If you want to be organic but the ground is heavy clay and infested with oxalis, or there are convolvulus vines and ivy invading over the neighbour’s boundary fences, or it’s a lifestyle block covered in gorse, walk away. You’ll thank me later! Otherwise, be prepared to put in some serious hard slog, and possibly resort to chemical use, to clear these weeds. Know your limitations. DON’T BUY A FIGHT. 2 GET RID OF NASTY WEEDS before you plant anything. If you’re unlucky enough to inherit an existing garden choked with tenacious weeds such as blackberry, convolvulus or twitch/couch grass, my advice is to reach for a hard-core herbicide, spray it off, wait a few months for any regrowth, spray again, then try to dig out as much of the dead growth as you can. If you don’t nail it at the beginning, you’ll be forever fighting (and losing) the war. I hate using chemicals but I honestly believe it’s better to hit noxious weeds hard, then begin the process of rejuvenating the soil with compost and mulch. This might take a few years, but if you’re in it for the long haul, then it’s worth getting it right from the get go. This also applies to knocking off existing turf before putting in new beds; one spray with glyphosate can be the lesser of two evils if you hate spending your weekends weeding.

If you are making new garden beds (or clearing old areas) but haven’t the budget to buy all the plants you need to fill them, INVEST IN A LOAD

OF MULCH. Or hire a heavy-duty mulcher and recycle your own green waste. (Note that fresh, hot mulch effectively smothers emergent weed growth but also robs the soil of nitrogen as it breaks down.)

4 MULCH ALL UNPLANTED

SOIL, laying it on 10cm thick. Not only does a generous layer of mulch conserve soil moisture, any weeds that do manage to push their way up will be much weaker and therefore easier to pull out.

If you do nothing else at this time of the year, DEADHEAD FLOWERING WEEDS

before they shed their seeds and spread. Just lop off their tops to break the cycle. You can dig the roots out later.

7 DON’T COMPOST SEEDING

WEEDS. Cut off the seedheads first, as the heat generated by a home compost heap may not be hot enough to render them unviable. Collect weed seeds in a garbage bag to dispose of with your household rubbish.

PESKY WEEDS IN PAVING

To evict weeds that have taken up residence in the gaps between bricks, pavers or cobblestones, use a natty hook-shaped wire weeder (available for just a few dollars at garden centres). Or RAID YOUR KITCHEN CUTLERY DRAWER

as forks and serrated steak knives also do the trick. Just remember to put them back.

To future-proof against weed growth when laying new areas of paving, pay a little extra and use a GRADED

STABILISING PAVING SAND such as Pavetight, Pavelock or TuffStuff Polymer Sand (from building suppliers hardware chains). These all pack down firmly to stop weeds getting in, and ants digging sand out.

To keep brick paths and paved patios weed-free for up to one year with just one application, try using a LONG-ACTING HERBICIDE such as McGregor’s Path and Patio or Kiwicare’s Weed Weapon Long Term.

Or for a natural alternative, pour BOILING WATER, SALT OR NEAT VINEGAR

directly onto patio weeds. (These methods are ideal for small problem areas but aren’t very practical for large garden beds.)

In a large vegetable garden, USE A LONG-HANDLED

PUSH HOE to keep the soil clear between rows. Sow or plant in rows at least 30cm apart so you can walk up and down to easily hoe out any weeds that pop up. Once your vege crops are established, they’ll shade the bare soil and naturally crowd out any weeds that try to get a foothold later on.

If you grow your own food in a potager or raised beds, simply IGNORE RECOMMENDED

SEEDLING SPACINGS on seed packets or punnets and overplant. Jam everything in closely, about 10-15cm apart, leaving no room for weeds to grow. You can also intercrop with fast and slow crops (radishes and carrots, for example) to fill up gaps where weeds would otherwise take root.

Oxalis bulbs cluster together like cloves of garlic, so digging around them tends to dislodge the baby bulbils and spread the problem. NEVER

LET OXALIS SET SEED as it also spreads quickly this way. If you choose not to spray, try heavy mulching or laying down black plastic over oxalis-infested soil in summer to weaken the bulbs. You can also carefully dig out and sieve the soil to remove oxalis bulbs, or simply overplant with evergreen shrubs to shade them out.

I’ve said it before and I’ll say it again: PLASTIC WEEDMAT IS EVIL AND INEFFECTIVE.

It might stop weeds in the short term but eventually they will grow in the dust and debris that settles on top of the matting, and in the long term it kills all the life in the soil below it, compromising the growth of anything planted in pockets cut into it. Plastic weedmat starves the soil – and all the organisms living in it – of light and water. It’s far better to lay mulch around young trees, shrubs or native plantings.

17 There are plenty of NATURAL WEEDMAT ALTERNATIVES

that do work, such as mulching with grass clippings or bark chips laid over corrugated cardboard, recycled coffee bean sacks or any other material that is both permeable and biodegradable.

Trying to wrestle back control of a bank, driveway or street verge covered in unwanted agapanthus? AIM A WATERBLASTER squarely at those thick, fleshy roots. This helps dislodge their grip on the soil so you can get a sturdy fork in to lever them out.

To get the upperhand over white, purple or pink-flowered oxalis, use Death to Oxalis

(from garden centres). For creeping oxalis, spray with Kiwicare LawnPro Prickle and Hydrocotyle. For large yellow-flowered oxalis, a glyphosatebased spray is best.

19 Get to know your enemy before you launch into battle. Pesky perennials and annoying annuals have different habits, from creeping to seeding. If you can find their weak point and exploit it, it might just give you an edge.

Keep hens. Free-range chooks don’t discriminate between your weeds and your special plants; they’ll scratch out the lot. So fence ’em in over a patch of wandering tradescantia and let them deal to all the top growth. In my Hunua garden, we built a portable chook run the same size as my vege beds – when the crops come out, the chooks move in to weed, feed and turn over the soil.

A CURE FOR CONVOLVULUS

The worst weed in my Hunua garden, by a country mile, is convolvulus (bindweed). And what’s worse, I only have myself (or my husband) to blame for its arrival, as it came concealed in a “free” load of topsoil. My second mistake was not taking it seriously enough when it sneakily snaked through my rose garden. Had I attacked when it first emerged, I may have stood some chance in actually being able to successfully eradicate this curse of a colonial introduction.

There are a few different morning glory species classified as weeds in New Zealand, and their flowers range from bright blue/ purple to pale pink and white. All have the same vigorous vines, which clamber through other plants, including hedges, shrubs and trees. Each vine can cover several metres in a growing season.

I tried to tackle convolvulus organically, digging out all the soil in the bed it was in, and methodically sifting through it on a tarpaulin, but it made no difference. This awful weed can grow from the tiniest root segment, so trying to dig it out only made it worse. It got into my compost heap, slipped out under the hornbeam hedge and has now colonised a whole hillside of flax and part of the adjoining paddock.

I’m afraid to say that convolvulus is a complete curse, and as such is a job for the big guns. Pull out as much as you can and spray what’s left with the strongest spray you can get your hands on, such as Yates Woody Weedkiller, Associate 600, Banvine, Escort, Meturon or Mustang. Glyphosate sprays knock it back too, but this is a long-haul battle. Repeat regularly, every few months, year-round.

22 BE RUTHLESS IN SPRING.

Weeds, like most plants, grow fastest in spring when the soil is warm and moist. That’s also when they are easiest to yank out (as their root systems are still developing) and spray (as their foliage is actively growing). Spring weeding also equals less seeding.

In summer, TURN OFF THE

TAP to your irrigation system and water by hand instead. Weeds are cunning – they flourish in the moist spots around irrigation nozzles and along soaker hoses, but will die if deprived of a water supply. Don’t give them a drop.

Spraying off a large garden area? It’s a good idea to ADD MARKER DYE to your sprayer so you don’t use more than is needed, or soak the same ground twice. Also, don’t jump the gun to repeat spray. Wait a few weeks to see the results first. (Pictured above is creeping buttercup 10 days after spraying with glyphosate.)

To improve your soil health and eliminate weeds at the same time, USE COMPOST AS

MULCH. Immediately after planting out vege seedlings, cover the bare soil around them with a 5-10cm layer of weedfree compost. This warms the soil to boost their growth while blocking light to any weed seeds in the soil that have been disturbed during soil preparation. Oddly, many weeds actually prefer poor soils to lovingly composted ones.

In sunny spots, it’s possible to smother sprawling and spreading weeds such as periwinkle or kikuyu grass by “cooking” them under a sheet of black plastic for a few weeks. But did you know you can also use clear polythene in a similar way to prepare sunny raised beds? This method is known as SOIL SOLARISATION and it deals to both weeds and soil-borne diseases. Lightly cultivate and water empty beds first, then peg down clear plastic sheets and let your soil steam-clean itself for 4-6 weeks prior to planting.

WATCH YOUR WEEDS GO

UP IN SMOKE with a gas-fired flame weeder. Buy a long-reach attachment (from www.hunkin.co.nz) for a standard LPG gas bottle or get up to 90 minutes of flame-throwing action from a weed wand and propane/butane tank combo from Mitre 10 or Bunnings. While it’s satisfying to instantly incinerate weeds, be careful not to accidentally set fire to any other garden features while you’re at it.

GIVE YOUR GARDEN SOIL

A DEEP SOAK the night before you embark on a big weeding session. Weeds, especially deep-rooted species, are far easier to extract from moist soil than hard, dry soil.

Preparing to spray? Dress for the occasion. Don a mask, hat, gloves, trousers and covered shoes and go op-shopping for long-sleeved

shirts to cover your arms. Hop in the shower and have a good scrub when you’re done.

Get down to their level and HAND WEED

ON YOUR KNEES. For comfort, sit down on a padded kneeler, armed with your choice of hand tool, be it a small trowel, fork, multi-pronged cultivator or Niwashi. Weeding slowly, and carefully, is the best way to learn how to spot the difference between seedling weeds and self-sown freebies worth keeping. In my vege patch, hand weeding this way has saved many a self-sown lettuce, tomato and tiny tomatillo, as well as zinnias, rudbeckias and, this year, even sunflowers!

Get a separate compost bin for your worst weeds to ensure that anything that survives the composting process is safely contained in one area. Sow pumpkins on top of the heap in summer; their large leaves and vigorous habit should crowd out any seedling weeds.

SAFER SPRAYING 32

If hand-weeding and mulching aren’t cutting the mustard, there are several ORGANIC PLANT-DERIVED WEED SPRAYS you can turn to, such as Green Assassin, Hitman, Agpro Bio-Safe, Yates Nature’s Way Organic Weed Spray and Kiwicare’s Bio-Gro certified Natural Weed Weapon. These sprays have natural fatty acids as their active ingredient, rather than chemicals. As a consequence, they tend to smell a bit squiffy, like rancid cooking oil. However, when applied on a hot, sunny day, they break down the plant’s cell walls on contact, causing the weeds to immediately wilt from a lack of moisture. Although less effective on cloudy or cool days, their big advantage is their rapid action: you can watch weeds shrivel up to nothing within an hour or two, which is ideal for last-minute crisis weeding before garden parties and garden club tours! Even when using organic sprays, always wear protective clothing and read the label first. I accidentally burned the skin off my arms the first time I doused myself in a pine-based, certified organic weed spray.

The same rules apply for all herbicide use. Only SPRAY

ON STILL DAYS to avoid spray drift to desirable plants; never spray flowering plants where bees are gathering pollen and nectar; don’t spray where pets play; and don’t spray near waterways.

Wild blackberries evoke nostalgic foraging memories for Kiwi kids who had a country childhood, but these noxious brambles are now a serious pest in rural areas. To tackle small areas of blackberry, GET A GOAT.

Large infestations will require repeat spraying in late summer and autumn with high-strength herbicides containing ingredients such as metsulfuron-methyl, triclopyr, picloram, aminopyralid or a combination of these ingredients, such as Escort, Conquest, Yates Woody Weedkiller or Tordon Brush Killer.

All will wreak havoc on nearby plants so it’s critical to avoid accidental spray drift.

If you only need to spot spray a few weeds, a simple way to REDUCE HERBICIDE USE

is to buy a 750ml trigger pack of pre-mixed spray, rather than filling up (and inevitably emptying) a 5-litre pump sprayer. Yates offers several handy ready-to-use sprays, such as Nature’s Way Organic Weed Gun (a vinegar and clove oil concoction) Turfix (for broadleaf lawn weeds), Zero and Zero Rapid, which shows results in one hour.

LOVE THY NEIGHBOURS 36

The worst pests – from pooing cats to noxious climbers – often sneak under or over boundary fences. But what’s a gardener to do when vines invade from next door? Talk it over first, as it’s feasible that the ivy that annoys you is an attractive feature over the fence, or perhaps your neighbours have valid health reasons for not using herbicides. You are entitled to cut back all the unwanted growth on your side of the fence. Rather than spray, use the PLASTIC BAG

METHOD. Bundle together a handful of vine stems and tie them into a sturdy plastic bag containing neat systemic herbicide. The vines will take up the poison and slowly die back to the roots.

Within 15 minutes of cutting back, PAINT IVY STUMPS with a herbicide gel such as Cut ‘N’ Paste or McGregor’s Woody & Bulbous Weed Killer Gel. Or use a small paintbrush to apply a lethal dose of Yates Zero Tough or McGregor’s Woody & Scrub Weed Control. Repeat as required. It may take a few months to die back fully.

Double, double, toil and trouble: whip up a weedy witch’s brew in a barrel to RECYCLE WEEDS

AS LIQUID FERTILISER. Fill up a barrel (preferably one with a tap fitted) with weeds, add comfrey leaves, seaweed and manure and fill with water. Leave for at least six weeks, stirring once a week, until the liquid is dark brown and, shall we say, richly perfumed. To use, dilute to the colour of tea and apply in a watering can as a pick-me-up tonic for hanging baskets and crops in pots.

Can’t eliminate the negatives? Then ACCENTUATE THE POSITIVES! Weeds aren’t all bad news. When annual weeds erupt in a green stubble over recently cleared vege beds in spring, it’s a sure sign the soil has warmed up enough to sow your crops direct. And while stinging nettles are literally a pain in the butt (and anywhere else they touch), they provide a valuable habitat for beloved red and yellow admiral butterflies. And of course many weeds are also edible – add them to your salad bowl .

Make a weed cocktail for your compost heap. Gather pulled weeds and pile into a 40-litre plastic trug, top with water and set aside in a hot, sunny spot for 1-2 weeks to rot down. When the water is slimy and smelly, any weed seeds will no longer be viable. Pour the liquid over your compost heap. This also helps to save space in a compact plastic compost bin.

Because herbicide concentrates are designed to be mixed with water, they have been shown to be up to three times more effective when a “surfactant” is added to the mix. This helps the spray stick to the leaves when applied. When making your own DIY weed sprays (and insecticides), ADD A SQUIRT OF DETERGENT or liquid soap

to your sprayer to do this job.

Last Christmas my husband bought me a weedeater. Yes, we are still speaking because the whippersnipper in question was a Stihl lightweight, lithium-ion battery-powered model. I’m a little bit in love with it for tackling the grass under our fruit trees. But my point is: GET THE TOOLS YOU

NEED to weed the garden you have, and pay a little extra for ergonomically designed gear that suits your skillset.

What to do about clumping arrow BAMBOO? Few weeds are as tenacious as this thug. Hire a digger if you can to physically haul out the root mass, or hack all the stems back as hard as you can. When it resprouts, as it will, paint the emerging shoots with herbicide gel or spray with Amitrole or Gallant. Keep at it, repeating every few months, removing the roots if you can.

GETTING ON TOP OF PERENNIAL GRASSES

such as kikuyu, couch/twitch and paspallum – or indeed any creeping weed that has rhizomes and stolons – is a devil of a job. All are easier to eradicate before you start planting as they sneakily wind their way through other plants. If you can’t dig them out manually, spot treat by dabbing the stems with herbicide gels such as Cut ‘N’ Paste or spray with Gallant.

“A weed is a plant that has mastered every survival skill except for learning how to grow in rows.” ~ DougLarson,gardendigest.com

WEEDS IN LAWNS 45

I can live with most lawn weeds except Onehunga weed. If you want to walk around on your lawn in bare feet, GET RID OF PRICKLES and thistles with Turfix or Prickle WeedKiller from Yates, McGregor's Onehunga Weed Spray or LawnPro Prickle and Hydrocotyle from Kiwicare. Spray in spring and early summer before the prickly seeds ripen.

Some weeds aren’t really weeds but are unwanted growth from good plants. ROOT SUCKERS around specimen trees growing in lawns are one such case. Ornamental cherries and robinias routinely throw up annoying suckers which can’t be sprayed (you’ll kill the parent tree) and mowing them down seems only to result in more suckers. The most effective way to deal with them is to cut the stems just below the soil surface with a very sharp knife or pruning saw.

WEEDS AS BABYSITTERS?

Lawn weeds keep kids amused for hours, making daisy chains, picking dandelion posies (below), crafting grass whistles and shining a light on chins with cries of “who likes butter?” Why spoil all their fun for the sake of a perfect lawn?

scratch and

dispatch moss from damp, shady lawns but it will always return. If you can’t improve drainage or increase the sunlight levels by pruning overhanging trees, apply sulphate of iron. Because moss prefers a low soil pH, sifting with baking soda also does a good job.

Spot spraying large lawn weeds leaves unsightly holes. Better to target dandelions and daisies early in spring with a DAISY GRUBBER.

That’s right; there’s a tool specifically for this job. Available as both a hand tool or long-handled model, its blade has a nifty V-shaped nick in the middle for levering out broadleaf weeds. Also comes in handy for getting the lids off old paint cans!

I reckon the best approach to managing weeds in our gardens is to AIM FOR AN

UNEASY TRUCE. We might not much like weeds, but birds, bees and beneficial insects aren’t so fussy about their habitats. Perhaps we should focus on eradicating the noxious nasties that invade our bush and try not to fret about backyard intruders. After all, in the history of humanity, not a single weed has ever been completely eradicated by herbicide. And it gets worse: a few years ago, a study by ecologists, who compared century-old Oxford University herbarium specimens to their living descendants, found that common weeds such as ragwort, speedwell (below) and willowherb are actually evolving to grow taller and faster but with much smaller leaves for sprays to get at. As gardeners, we might just have to accept that we can’t win them all… ✤