How to Beat Perennial Weeds Using Mulch

, written by Ann Marie Hendry gb flag

Mulching a fruit garden

There is nothing more discouraging than fighting a losing battle. I suspect that one of the main reasons new gardeners give up on their dream of growing their own fruits and vegetables is the seemingly endless onslaught of perennial weeds that simply refuse to back down!

Perennial weeds are those persistent blighters that regrow each year, as opposed to annual weeds which germinate, grow, flower and set seed within a single year. Annual weeds are weaklings that can be dispatched with a sharp hoe – but perennial weeds are much more resilient.

Dousing weeds with weedkiller is not an option for organic gardeners, and indeed is not usually practical when they start growing up through your fruits or vegetables. That leaves us with a couple of options.

Perennial weed roots in a wheelbarrow

The Hard Option: Digging Out Perennial Weeds

If you’re feeling fit and keen, and want to completely clear your garden of weeds in one go, you can (try to) dig out every last scrap of weed root by hand. This is particularly difficult with weeds such as ground elder and buttercup, which spread by rhizomes that snap easily as you try to pull them out, regrowing from the tiniest scrap of root left behind in the soil.

Don’t, whatever you do, use a rotavator in an effort to clear the ground more quickly – the blades will chop the weeds up into tiny pieces, so if you had 50 weeds before, you’ll now have hundreds, if not thousands!

Hand-digging weeds takes a long time and even small areas can be very hard work. If you have a large area to deal with, don’t have time for such an intensive process, or would prefer not to give yourself chronic backache, there is another option.

Grass clippings for use as vegetable garden mulch

The Easy Option: Organic Mulches

Mulching is an excellent method of perennial weed control. It provides a barrier that keeps weeds well below the surface, where most will eventually die due to lack of sunlight. Mulches work particularly well around perennial crops such as fruit trees and bushes, but can be used with annual crops too. It’s not an instant solution, but it will help you to keep on top of weeds and does away with regular epic weeding sessions.

Landscape fabric can be used but is not, in my experience, a great idea. It’s a quick fix, but eventually it will need attention. The fabric will degrade and break up over time, allowing weeds through. Removing weeds that have their roots tangled up in landscape fabric is, quite frankly, a pain in the bum.

Organic mulches, on the other hand, are wonderful because they not only suppress weeds but help to build better soil over time. This gives them a clear advantage, not only over landscape fabric, but over digging out weeds too.

Newspaper mulch in a fruit garden

The first thing you need to do is put down a weed barrier. Newspaper is ideal (cardboard is okay too) as a permeable, completely biodegradable, soil-enhancing alternative to landscape fabric. Lay your newspaper five or six sheets thick and overlap them generously to avoid gaps that weeds could push up through, then soak it well. Cover the newspaper (or cardboard) with at least two or three inches (5-8cm) of loose, well-rotted organic mulch.

Well-rotted garden compost, manure, sawdust, shredded bark, leafmould, coir, or a mixture of organic materials, all work well as mulch.

Maintaining a Weed-Suppressing Mulch

It’s important to replenish organic mulches as they rot down. This does make them more work than landscape fabric, but you will be rewarded with rich, friable soil. Grass clippings or straw can also be used to top up your mulch. Add another inch or two of organic matter every couple of months, or more often if you like. For instance, once or twice a month I will spread grass clippings from mowing the lawn onto my fruit and vegetable beds.

Raspberries with grass clipping mulch

I won’t lie – occasionally a weed does force its way through. But not many! And any weeds that do make it through can simply be yanked out by hand. Don’t worry too much about getting every last scrap of root, as you’ll continue to mulch and keep weeds below the surface. Tearing off the top growth means the plant can’t photosynthesise, so each time you do this, the plant weakens. You’ll probably find that annual weeds germinate in the top layer of mulch, but a quick scruffle over with a hoe every week or two will see these off.

To begin with, avoid using tools to lever any weeds out of the soil, as you will risk puncturing the newspaper layer. In the second year you can start using a tool to help remove any really persistent weeds if you wish. A dandelion weeder, incidentally, does a stellar job of uprooting just about any weed I’ve encountered; its twin prongs get right under the crown of the weed and make it easy to lever it out with minimal soil disturbance.

If you’ve got any tips for (or questions about) keeping on top of perennial weeds, drop us a comment below.

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Comments

 
"I just started this method of weeding this garden year and can already see amazing results! I've read another article that it takes about 3 years to really see the benefits but I am already happily surprised! I had an awful time with my garden last year-the grass that grew was unmanageable and chocked out my tomatoes and some of my peppers plants!"
Sarah M on Friday 17 June 2016
"Make sure the grass clippings don't include seeds. This can cause more trouble than good."
gary on Friday 17 June 2016
"Great to hear that you're finding success with mulching Sarah. The fruit bed in the pictures above is now in its second year - in the first year, weeding was minimal (5-10 mins every 3-4 weeks before adding more mulch), and I've hardly had to pull any weeds at all this year so far. The plants are doing fantastically well too. The greatest challenge with mulching is sourcing enough mulching materials, and as Gary says above, it's best to avoid using grass that has produced seeds (regularly mown lawns will usually be ok though). But as someone who has done more than her fair share of weeding in the past, I'd say that mulching is well worthwhile!"
Ann Marie Hendry on Friday 17 June 2016
"I also have an issue with things that I want to come back from seed or roots. I can't cover them up with mulch or they won't come back. By the time they get large enough to tell the good from the weeds, the weeds have already taken over. "
Robin on Friday 17 June 2016
"Hi Robin. If you're planting into a weedy area that you're controlling with mulch, it's best to sow your crops in pots or in a weed-free nursery bed, then transplant them when they're bigger. You'll become very familiar with your crops when you're looking after them in pots, and you'll learn to identify them at their seedling stage, which will be invaluable in future years. For perennial crops that die down or are cut down over winter and return next year, a good tip is to mark the location of each plant with a cane or a stick before it dies down. That way you'll know which areas to avoid mulching too thickly (a thin layer will be fine), and you'll know which plants are your crops when they poke up in spring."
Ann Marie Hendry on Friday 17 June 2016
"There is a pellet stove sales nearby. It is an excellent source of heavy duty cardboard in very large sizes. I keep a stack handy and overtime, it becomes more pliable as it has been rained on. Then I cover with a organic mulch. Perfect for trailing veggies such as cukes, melons and squashes."
Karlene on Sunday 19 June 2016
"I try to grow my veggies without sprays etc. so I'm concerned that the ink on newspapers and the additives in cardboard will contaminate my soil. Am I worrying unnecessarily?"
Arline Smith on Monday 20 June 2016
"What do i do with the huge bundles of weeds i pull up in my garden? I live in thcou try ad w e di not have a green garbage bin to put in garden waste. Thank you Mary"
Mary on Tuesday 21 June 2016
"Bundles of weeds make good mulch. They should be thoroughly dried out to prevent re-rooting. I usually put them in a bucket until I know they are dead. Depending on the maturity of the weeds, it may add weed seeds to your garden. However, it is effective mulch and no need for a green garbage bin."
Karlene on Wednesday 22 June 2016
"Something new I'm trying this year in my asparagus patch. Pine needles. I live on the edge of the Pine Barrens in NJ, but, those are short needles and don't work well. You need the long needles from the south. Hard to find here. I did find one store that had them. They were 12.99 a bale. A little steep. They are 3 or 4 bucks in the Carolinas. The advantage to the long needles is that they intertwine and form a carpet that the wind won't blow away. So far, I'm very happy with their performance."
Bob Fanucci on Thursday 23 June 2016
"Weed growth is a serious issue as it affects the growth of plants. As a gardener, I keep looking for different methods to control weeds and I hope this will surely help. Hendry thanks for sharing this."
lucio bovolini on Wednesday 29 June 2016
"Hi Arline. Most newspapers use vegetable based inks, which in my opinion is unlikely to contaminate your soil with anything nasty. You may want to be careful about using cardboard containing glues or other additives. There's a lot of debate about this but no definitive answers, so I'm assuming innocent until proven guilty. Mary, most weeds can be composted. If you have perennial weeds they'll need to be composted for at least 2 years to ensure they've died off completely, and you'll need to make sure you exclude all light - a plastic compost bin is ideal. Alternatively, you can drown them in a bucket of water for about four weeks, or spread them on a flat surface to dry out in the sun for a few weeks, and they can then safely be added to your regular compost heap or bin, or if dried they can be used as mulch as recommended by Karlene above."
Ann Marie Hendry on Tuesday 5 July 2016
"Thanks for confirming that newspaper mulching is not harmful. I think of myself as a lazy gardener so have used this method for years but heard much criticism about it as ink contaminating. I manage other weeds - like in carrot patches, by spending 10 minutes or so pulling some out every time I harvest. I think of it as payment for the harvest and have been teaching others who harvest from my garden to do the same. "
Donna on Saturday 17 December 2016
"'Payment for the harvest' - what a wonderful idea! I think I will adopt this approach too in future."
Ann Marie Hendry on Saturday 17 December 2016
"Thank you. Always looking for ways of making things easier, and this has a double benefit of weeding and feeding at the same time. Im going to share to my page for others to see - thanks. www.facebook.com/madgardeninglady"
Leesa Mckendrick on Monday 19 December 2016
"Thank you for replying to my question concerning ink contamination. I'll be happily recycling my local newspaper next Spring. :-)"
Arline Smith on Saturday 24 December 2016
" I have used this method of weed suppressing and find it effective. My allotment has bindweed and I find that it rises to the newspaper and travels along the ground often for metres in just a few weeks in the growing season, eventually surfacing where there is light. I have tried using weedkiller aimed down a plastic bottle to avoid contaminating other plants and often it appears to kill bindweed but it returns in the next growing season. I find the best way of controlling bindweed is dig out a small section of soil and put it in a wheelbarrow, then systematically sieve through the soil and remove every small piece of root. If possible fill the lower level with grass clippings, then nettles without roots, then leafmould, then compost and finally clean soil. Any bindweed that grows in this top level can be pulled out in it's entirety. It is backbreaking work but organic. You should end up with a raised bed which is more accessible, and easier to top up with compost when the produce is removed. If you can avoid treading on the soil then the soil is very loose and makes the removal of bindweed easier. When planting seedlings firm around the plant but not the surrounding area. Also I use rhubarb leaves as a weed suppressant around young plants , replacing them when the leaves disintegrate. I have not found them poisonous to the ground."
norm kaczmar on Wednesday 13 June 2018
"Good tips Norm. Bindweed is a tough weed to get on top of! Loose soil helps, as you say - I've found that mulching, and avoiding stepping on the soil, makes it much easier to remove plants that spread by runners under the soil surface (ground elder for instance)."
Ann Marie Hendry on Tuesday 19 June 2018
"I am part of a group making a Forest garden in a local allotment in Suffolk, England. There are five strips of perennial mainly woody planting, and four very wide paths between them. The paths were covered with cardboard, then a couple of inches of chippings (waste from a local hedge cutter/tree surgeon). It stops the soil seed bank germinating but perennial weeds keep on popping up, mainly nettles, some dock, increasing amounts of couch grass (creeping wild rye. So far, we are simply putting down another layer of cardboard and another couple of inches of chippings about twice every year, but the paths are getting higher and higher and it seems a lot of work for not very efficient weed control. Any better ideas? PLEASE??"
Deborah Pratt on Sunday 25 November 2018
"I've found that very persistent weeds like nettles, docks and thistles will push through to begin with. Make sure to overlap the cardboard very generously (several inches) to make it hard for weeds to filter through the gaps and up to the surface. Pull any weeds out when you see them (or as much as will easily pull out by hand, without digging) to prevent them from photosynthesising, and you should be able to gradually starve them out. It's not an instant solution, but between that and the impact of regular foot traffic as you walk on the paths I reckon you should be able to mulch just once a year and the paths will get flattened as you tread on them. It might also be easier to lay a four-inch thick layer of chippings once a year than topping it up midseason. Believe me, it's much easier than hand-weeding an unmulched bed!"
Ann Marie Hendry on Wednesday 5 December 2018

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