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Can anyone help i have 2 acres of garen with an awful lot of Crocosmia growing in it. I have tried to get rid of it with no joy it grows back stronger than ever.

How can i kill / remove the crocosmia so that my other plants can thrive?

Hi Manxlad, I have just found out that I have the same, I'm going to dig up the corms and see what happens.... It's unreal and growing just everywhere! I'll let you know how I get on ... But I think now is the right time to do it before it starts really comng to life in the spring.

I had a lot of Crocosmia that had to go due to the garden being altered. Mine was only a small amount but I dug the corms up, saved some of  them and put them in pots. We did put Round Up on the ones that were left as they continued to grow and that seemed to help a lot. Where my crocosmia were, we have made our driveway larger so concrete works a treat. 

Does the round up not effect the other plants or the soil?

Some plants are just so invasive.    I had the same problem with crocosmia, and found it was just a case of keep at it.    Eventually I had taken enough corms up and confined it to a clump.    More do keep coming up, though, but after rain I find it quite easy to simply pull them out where I do not want them.     I also have the same problem with muscari or grape hyacinth.    I have been removing these from part of my garden now for a good two years, but there are still plenty there.   Perhaps another year of pulling them out, digging them out, etc., wuill do the trick, if I am lucky!



Manxlad, my Crocosmia were in a bed on their own, so I had no problem with other plants which made the job a little easier.

Any one who plants this plant and day lillies must be crazy. They a a pain in the butt!!!


Gardening Grandma

I'm one of the crazy ones, then, because I like both plants, though one does have to keep on top of them.

Manxlad, Roundup does not affect the soil. It can be applied to single plants by cutting them down and pouring Roundup into the stem or by using Roundup gel, but you do have to be careful. I use it on plants that come  up through my tarmac drive, such as alstroemeria, which is also pretty invasive, and they are always close to the borders and other plants.

I grow the cultivated hybrid crocosmia but I think it's the wild invasive montbretia that's the real villain.

I think glyphosate will work but sheer physical digging is the solution.  To dig up clumps...soil and all and to gather up the smaller corms too

I grow crocosmias and day lillies but keep them limited in size by regular splitting.  There are better perennials for the garden though

Gardening Grandma

Don't know if it is true, but I read once that wild montbretia is one of the plants that must not sent for council composting or other disposal, along with plants like Japanese Knotweed.. Presumably, it must be burnt to dispose of it. I have it (montbretia) in my garden but have managed to get rid of most of it. The named cultivars are nice, though, especially Lucifer, I think.

Yep lucifer is excellent.  Still vigorous though and I pot up large clumps to hide in border gaps.  They flower just as well but restrained

The way crocosmia spreads is something quite amazing.  I planted a small patch of 10 bulbs 3 years and which have spread quite considerably.  My soil is light so it's perfect for it.  I wanted to know how it spread so easily and what I discovered is that its not the corms that multiply (initially), but it send out tendrils several inches from the main corm, from which it then throws up some leaves, before moving the tendril on some more, before sending up more leaves  Where the little plant is then it grows a corm, and that also starts sending out tendrils in the soil.  Before you know it, you're over run!  I've now got crocosmia which are 2/3 feet away from where I initially planted the original bulbs.  I don't mind, because they are one of my favourite plants

Evening tim

You sound like a guy who thinks a bit like I do.  I need to find out how a plant might behave in my garden.  Invasive plants are a big no regardless of their beauty.  Euphorbia Fireglow, for example, is rampant and had to go.  Some artemisias are also thugs that will colonise for many yards in a season.

You are right about crocosmia though I think there are newer varieties that are less vigorous


You're right Verd and Tim about checking the conditions for what you're planting.  The common crocosmia grows like a weed up  here (in damp clay soil) but I just dig it out if it's a nuisance. I had Lucifer at last house and it was really stunning- I loved it. I still like the common one but it's just a case of being vigilant.

My garden and yard have been taken over by Montbretia, too.  My husband threw a clump of dug-up bulbs in a pile of sticks he had stacked up on the side of the house, and those things *still* managed to grow and bloom!  If you ever want to get revenge on someone, just drive by their house at night and throw some crocosmia and English Ivy in their yard.  It's the gift that keeps on giving. 


flowering rose

I am afraid it is very persistent and what ever you do it will always find away back.So its dig up as much  as you can and put the corms in the green bin.This plant has already escaped into the countryside and like the day of triffids its a big problem unless kept in check.

I'm really concerned about using glyphosate on the crocosmia which is coming through a layer of weed membrane and gravel. We have hedgehogs, grass snakes and many birds - will they be harmed by glyophosate?



As chemicals and poisons go Glyphosate is one of the safer ones. It doesn't kill animals. None of the animals you mention will be eating crocosmia anyway. Glyphosate doesn't affect the soil

Thanks, but I'm concerned at them brushing against it...


That isn't a problem jmeds. Once it's dry it doesn't affect anything. Choose a good warm day, and it will be dry very quickly.