When Tiritiri Matangi supporters started revegetating the Hauraki Gulf island in 1984, it was New Zealand's first such project. My family became supporters in the 1990s, had some great times and met a fascinating bunch of people. Our main task was helping to build penguin boxes and dealing with weeds - including cutting out a giant box-thorn plant which managed to set itself afloat on the high tide and drift out to sea like a spiky brown iceberg.
By then, the trees which had been planted decades earlier were well grown. I remember one of the old hands saying that their main issue with the earlier native plantings was that they hadn't thought about natural plant groupings and in certain parts of the island you could still see - many years later - where the trees had been planted in rows.
As spring gets into full swing, weeding becomes a big chore in the garden. The soil is warming and we get high rainfall - perfect weed-growing weather. When you are planting your garden, dot around sprawling groundcovers. In time, as the groundcover spreads, you'll have a seamless garden which resists weeds. Bare soil is like a scar in the land and will always attempt to heal itself. Whatever seeds are at hand will grow quickest, and weeds out-compete everything else.
Good gardeners anticipate this and save themselves more work in the long run. If you've just established a garden and there's plenty of bare soil, try brown box cardboard as a weed suppressant. First soak the cardboard to make it easier to handle, then overlap to prevent any light getting through. Apply a thick layer of shredded mulch on top - but don't pile it up against tree trunks or woody stems. I've tried different weedmats over the years and by far the most successful was cardboard.
Synthetic weedmats work in the short term, but down the track, as leaf litter and soil land on top, along come the weeds again, and you are stuck with buried weedmat.
There's nothing worse than planning to dig a hole and hitting old weedmat that's hard to dig through. The best thing about cardboard is that it's free and, in time as the material biodegrades, just scrape back your mulch and lay some more down if you have weedy patches starting again. Then cover it with mulch again. Simple.
Alternative weed mats
* Coir/coconut fibre - comes in large rolls, good for stabilising the ground and establishing wetland plantings as it eventually biodegrades. Not ideal if you're covering creeping grasses such as couch grass or kikuyu, as the rhizomes will be alive underneath, and start growing through in time.
* Wool weed suppressant - comes in a fine blanket-like roll, lovely and easy to roll on to bare soil and then plant into. It is designed to go over bare soil and help prevent run-off of soil, but biodegrades quickly as it is thin.
* Ecocover - recycled card and paper with hessian backing, impregnated with organic fertiliser. Easy to use, helps fertilise plants as it breaks down.
Free weed matting
* Carpet or old underlay - use only natural materials such as wool carpet with hessian backing. Avoid carpet with plastic woven through it and any with synthetic underlay. Good for laying under garden paths, then mulching on top as it lasts a long time. Not the best in the garden itself, as the soil stays dry underneath.
* Brown uncoated cardboard - easy to place around existing plantings. Soak first and use on damp, not dry, ground, overlapping edges well. Has to be covered with at least 15cm shredded mulch or it will look unsightly. Breaks down in time, but can easily be replaced where needed. Remember to first remove any packing tape or plastic from the cardboard.
