At one time, I thought this delicate pink-flowered plant looked pretty and harmless, until it started popping up in every crack, border and shady corner of my garden… I first noticed it in plants in pots we brought back from London, then it started appearing literally everywhere.
I really didn’t mind Herb Robert – also known as Stinky Bob (I’ll get into that later) – at first because of its tiny pink flowers and delicate fern-like foliage. However, after spending weeks searching for the best ways to kill this weed and preferably a natural way to do it, I’ve come to realise that this dainty plant is far more persistent than it looks. And this spring, it’s safe to say this “weed” is officially winning the battle I’ve been waging with it. Every time I pull some of it up, even more appear!
What makes Herb Robert so hard to get rid of?
Herb Robert (Geranium robertianum), or Stinky Bob as I prefer to call it, is a fast-spreading wild geranium native to the UK. Its nickname, Stinky Bob, comes from the strong chemical-like smell released when the leaves are crushed (it reminds me of petrol), which I now know all too well after countless weeding sessions.
While it’s technically a wildflower that has a multitude of benefits for pollinators, rather than one of the more aggressive invasive weeds, stinky bob self-seeds extremely easily, explains Richard Barker, horticulture expert at LBS Horticulture, which makes it hard to get rid of.
‘Stinky Bob is so hard to get rid of because each plant is capable of producing hundreds of seeds, and these are forcefully ejected from the plant, potentially to a distance of a few feet away,’ explains Robert.
‘This makes it hard to control the spread by simply getting rid of the parent plant, as it may have already launched seeds into the surrounding area. The seeds can also remain viable in the soil for a long period of time, and the plant is capable of thriving in virtually any environment.’
So you see the problem? Read on for how to control the pesky plant, or better yet, get rid of it.
The expert-approved ways to get rid of Herb Robert
Timing is everything with Herb Robert. Lucie Bradley, gardening expert at Easy Garden Irrigation, explains that unlike many weeds like bindweed, couch grass and dandelions, which are hard to get rid of simply because they will regrow from the roots which you leave behind, Herb Robert relies on seed production to spread.
So it’s important to pull the weeds from your garden before it has a chance to produce seeds, which is from late spring through to late autumn, making right now the ideal time to start removing them from your garden before any seed pods appear.
Here’s how to stop Herb Robert in its tracks before it takes over.
1. Pulling by hand
What you’ll need
GAVOROHANS
3 Pairs Gardening Gloves Superior Grip Work Gloves
HACHIEMON
Japanese Weeding Hand Hoe Gardening Weed Remover Tool
RAM
Heavy Duty Garden Waste Bags – 272 Litre – 3 Sacks
Richard explains that one of the most effective ways to deal with herb Robert is hand-pulling, especially when the plants are still young and before they’ve had a chance to set seed. Thankfully, the roots are relatively shallow, so they usually come away fairly easily.
‘When the plant is young, it can be easily pulled out by hand as the root structure should not be too complex at this point,’ he explains. ‘If pulling by hand, do this before the plant produces flowers to stop it from self-seeding. If you are trying to remove the plant from compacted soil, you may need to use a garden fork.’
Lucie says you could also use a grubber, like this Gardena combisystem weeder, £13.99 at Amazon, to easily loosen the weeds from the soil, so you can then collect them up, ready to dispose of them. If you prefer to weed without bending, Lucie recommends using a long-handled hoe, like this Dutch Hoe, £8.85 at Amazon, on a dry, sunny day to cut through the stems of herb robert, leaving the weeds to die.
She also recommends always wearing gloves (this bargain set of three gardening gloves, £5.97, is a bestseller on Amazon) when handling it, because whilst it’s easy to simply pull Herb Robert out of the ground, roots and all, the fine, fuzzy hairs which cover both the stems and the buds sometimes hold some of the clear, watery sap which is also in the weeds’ leaves and stems.
‘This sap will come out of the stems and leaves when broken, which is likely to happen when you are pulling it from the ground, and it’s this sap which can cause skin irritations,’ she explains.
Shop these weeding secret weapons
Root Slayer
Mini-Digger Shovel, Red
My mum and I swear by a root slayer, and it’s great for everything from planting to digging out roots.
RYOBI
18v One+ Cordless Handheld Cultivator
Gardena
Combisystem Hand Weeder
A good weed grubber is an essential bit of kit when doing a spot of weeding and our expert Lucie agrees. This Gardena weeder is a total bargain, too.
2. Smothering
An effective chemical-free way of clearing large areas of herb Robert is sheet mulching, explains Lucie, especially if it seems to keep returning to the same spots.
And Richard agrees that you can prevent Herb Robert seeds from germinating and growing by covering the soil with a thick layer of mulch. ‘Use a layer of organic matter around three inches thick, or you can also use ground cover plants,’ suggests Richard.
A thick layer of bark, compost or mulch helps block the light from reaching seeds and makes it harder for new seedlings to establish. Lucie says that using cardboard beneath mulch in heavily affected areas provides extra suppression.
‘When using this method, first cut back the Herb Robert, then, using brown, corrugated cardboard, cover the area, overlapping the sheets of card as you want to stop any light reaching the ground.’
‘Soak the cardboard layer with water and cover with three to eight inches of organic mulch such as garden compost or bark chippings (we’re big fans of RocketGro’s Magic Mulch, £18.98, Amazon), to both hold the card in place and block all light,’ advises Lucie.
‘After six to 12 months, the card will break down, but you will need to monitor the area, as if any seeds remain in the soil, they could still be viable and start to sprout if the soil is disturbed and they are exposed to light.’
Our favourite mulching options
RocketGro
Organic Magic Mulch – 50l
Westland
Bed & Border Chipped Bark 70lt
Thompson & Morgan
Incredimulch Plus
3. Boiling water for patio cracks
If you’ve got herb Robert growing in paving slabs, gravel paths and driveway cracks, Lucie says boiling water can be a surprisingly effective natural fix. However, she doesn’t recommend using it in garden beds and borders.
This non-selective method has the potential for you to damage plants you want to keep if the boiling water gets onto them, as it works instantly, rupturing the cell walls of plants so that they dehydrate, wither and die within a few days,’ she explains.
‘So if you want to use boiling water, this is most suitable for weeds growing between paving slabs or on pathways rather than in flower beds or borders.’
This method is particularly useful for isolated clumps in awkward spots where hand-pulling can be tricky.
How to prevent herb Robert coming back
Stopping herb Robert from returning is all about making your garden less inviting to it long term. Richard recommends never composting the plants that have already developed seed heads, as seeds can survive composting and end up straight back into your borders later on.
It’s also worth cleaning muddy boots, gloves and tools after weeding, as the tiny seeds can easily hitch a ride around the garden. Another suggestion is to replant infested areas immediately because exposed soil gives stinky bob the perfect places to germinate and spread.
‘Dense, ground cover plants can help with this, as they will quickly cover space and block the light from reaching any remaining seeds in the soil,’ suggests Richard.
This will help block light and crowd out seedlings. Flowering ground cover plants such as creeping phlox, hardy geraniums, and creeping thyme will work well in the shady areas that Herb Robert loves.
But most importantly, to stop this pretty but persistent weed from taking over, he advises that long-term monitoring is essential. ‘Stinky Bob seeds can survive in soil and remain viable for years. For this reason, you will need to closely monitor any cleared areas for a few years so any new seedlings can be removed quickly.’
Lucie advises that you’ll need to be patient and persistent when tackling herb robert, as it can take years to completely remove it.
‘Herb Robert seeds are very versatile, allowing them to germinate within a few weeks of falling onto the ground,’ she explains. ‘Or they can lie dormant in the ground from late winter and germinate the following spring. However, they can also remain viable in the soil for up to five or six years and simply germinate when the conditions are suitable.’
So Lucie explains you’ll need to be on the lookout for new weeds sprouting and nipping them in the bud as soon as possible.
If you enjoyed reading this, sign up for the Ideal Home newsletter for all the latest home decor trends and inspiration delivered straight to your inbox
Read the full article here