Listen To Bindii

Whether you call it bindii, bindi weed or bindi-eye, this prickly-seeded little weed is currently causing big problems in Pine River Shire, Brisbane.

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People are keen to control it, so they can sit or walk barefoot on their lawns. Fair enough, but people seem less willing to hear what bindii means in terms of good gardening.

Bindii, Soliva sessilis, is a common lawn weed. It’s an annual flat weed, that is, a low-growing, ground hugging plant. They germinate as seed during the start of the cool seasons, flower in late winter to spring, and set lots of small, burred seed. Most people are picking them out of their feet when they realise it’s been growing in their garden for ages…

Bindii says “Thanks!”
If bindii is in your lawn, it’s telling you that:

  • Your soil is compacted, and needs aerating;
  • Your soil is acidic, and needs sweetening;
  • Your turf is starved, and needs feeding;
  • You’re mowing your lawn too low;
  • Get your lawn into shape

Space out these tasks – never, ever feed and weed turf at the same time – it’s counterproductive, no matter how alluring chemical company advertising is.

When is the ideal time to start controlling bindii? In Queensland you can start in August, in NSW start in September.

Weekend 1
Raise the height of cut. Most mowers can be adjusted to cut grass on at least a high or low setting. Shaved turf develops bald patches, inviting weed invasion. Turf cut high naturally smothers many lawn weeds.

Mix 2 tablespoonfuls of iron sulphate, (commonly sold at hardware stores & garden centres) into 4.5 litres of water. Use a watering can and rose to sprinkle the solution over the bindii, ensuring it’s foliage is wetted. Promptly wash any splashes off paths, paving or plants with clean water.

Use a fork, or hire an aerator, and aerate your lawn. This helps rain and air to get into the soil, helping your turf to develop a healthy root system.

Weekend 2
Sprinkle one handful of dolomite per square metre. This sweetens acidic soil and replenishes its magnesium, invigorating turf.

Weekend 3
Sprinkle one handful of certified organic poultry manure or, better still, blended manure such as Rooster Booster, per square metre. This feeds soil micro-organisms, and helps replenish nutrient deficiencies whilst stimulating robust turf growth.

Cultural controls for success
Long term control of bindii means consistently improving your lawn care. So repeat this three week programme in autumn and spring.

Most people just want to know about the quick fix bindii control. My grandad’s iron-based remedy, over a hundred years old, kills bindii in 24 hours, and most people leave it at that. But bindii seed remains viable in the soil for many years to germinate in bare patches. Repeated applications of iron sulphate in itself isn’t the answer, because it gradually acidifies the soil, favouring bindii.

The worst mistake is to buy the popular ‘weed & feed’ chemicals. The herbicides they use are dangerous and they’re unpredictable. Developed for use in a cool temperate climate, these highly volatile poisons rapidly evaporate when temperatures exceed 21˚C. Poisonous vapour is easily wafted by breezes to damage plants – often your neighbours’. And residues continue evaporating, poisoning for longer than you’d expect – lawns become toxic hazards for kids, pets and wildlife.

Iron sulphate solution is not volatile. As it breaks down it releases iron, a tonic for plants.

I expect that gardeners and councils all around SE Qld are spraying their sick turf with volatile pesticides right now. But there’s no short cut to good turf.

What are your weeds telling you?

Jerry Coleby-Williams