Two Invasive (Possibly Rhizomatous) Weeds - How to Deal With Them?

Hello and thanks in advance for any help.

I moved in to my new house around a year ago and I have two species of weed that are proving to be particularly aggressive. I have pulled them up (with as much root as possible) when i have had the chance, but now we're hitting spring I am starting to think that the weeds are now winning the battle.

Both of them seem to be very deep-rooted and are spreading without flowering, which is why I think they may be rhizomatous (I am aware of this concept only because I had a Japanese Knotweed problem at my last house - some people have all the luck eh?).

Here is Thing 1:



I am almost certain that this is Ground Elder (Aegopodium).

I understand that the best thing to do would be to move all the wanted plants out of the area and then dig up the whole area to take out the whole root network of the ground elder. However, it is growing up through large areas of our lawn so this is not going to be possible everywhere. Would a gel weedkiller be any use, or will the roots/rhizomes just keep sprouting?


And Thing 2:



I am not at all sure what this is, but my buest guesses so far, based on ID guides, are:
Teasel
Foxglove
Alkanet

Once they get reasonably large (5cm+ leaves) the stalks are spiky and uncomfortable to handle without gloves.

They seem to keep growing back, and appearing in new areas, no matter how many times I pull them up.

Any suggestions on what this is, and how I can deal with it?

Thanks

 

Hello Dave and welcome to GC.

You're right on both counts - first one is ground elder, second one is alkanet.

For ground elder, something like Roundup gel would work, or you could try a selective lawn weedkiller where it's invaded your grass. It may need more than one application to completely eradicate the ground elder, but it can be got rid of if you're persistent.

Alkanet tends to have deeper roots, so trying to pull it up will just snap the top off and leave a live root just below the surface, ready to grow back again. It can be dug out, the best way is to use a spade and dig down alongside the plant to the full depth of the spade, then lift out the root. This should get most of the root out. Any root still left behind may grow back in time, but digging it out to that depth will have weakened it and you will beat it eventually if you dig out any further shoots as soon as they appear.

Roundup will also work on alkanet.

 

Thanks Trunky.

I had considered that the suggested remedies could range from "use some weedkiller" to "hire a JCB" so I'm happy that it seems to be closest to the former!

 

For the lawn weeds use Verdone Extra.

 

I dont think? either of these are common lawn weeds, are they???

Shouldn't regular mowing sort them out?

 

I can confirm that they both grow back after mowing.

Thanks for the weedkiller suggestion, Dai.

 

I was weeding a bed with Ground Elder in it the other week. While it was all over the bed, none of it was in the grass adjoining it, so I guess it can't suvive regular mowing.

Some folk have said the best way to control it is to start eating it. That's ok if you like aniseed flavoured shoe leather I guess

 

Ground elder and Green alkanet... such wonderous... and stubborn weeds.

If they're both in your lawn, quite possibly the only control (apart from digging up the entire lawn to at least 2-3 + feet) is using a selective herbicide. Not the stuff you can buy in a hardware store - but something like Kaskara from eBay or a company called Agrigem. It will set you back £50 to £60 for a litre but a litre goes a very long way as only 3ml of it is needed per litre of water.

Kaskara kills pretty much everything except grass. It absolutely annihilates field horestail foliage within a few days, which Glyphosate weedkillers barely touch.

I have used it on Ground elder in lawns and it did a good job but took a couple of applications to eradicate it as the roots are rhizomous are quite shallow.

For weeds with tap roots, it may take a few more sprays. Have used it on large dandelions and they seem more resilient in comparison to Glyphosate, but eventually keel over. Green alkanet tap roots, from personal experience, can be up to 2ft long and well over an inch wide. They are abolute beasts and spread through seeding or fragmented tap roots (when drying to dig 'em out), but are not rhimozomous like ground elder. This one may be a bit more tricky but a decent selective weedkiller like the one mentioned above should eventually solve the issue.

 

Argh, so there's the "hire a JCB" end of the scale...

As i have already ordered a general lawn weedkiller and a gel weedkiller I will probably give that a try initially and look into the Kaskara if the weeds are still winning in a couple of months. It's a shame it can't be bought in smaller quantities, as the lawn is only about 100m2 so I would only need about 50ml even if I had to repeat three times (according to my calculations).

Thanks for the extra opinion.

 

No mention of JCB hire. More a suggestion of 'elbow grease' to keep the costs down.

Keep us updated on how the treatment works!

Kaskara has been discontinued by the manufacturer but is still currently available, while stocks last.