only in your dreams...

since round up kills just about anything I would say it is not safe for your cactus but I am not expert by any means.

I don't think it will kill it.

Have you considered a pre-emergent?

I'd use an early weed control, then I'd mulch the area immediately around the cacti.

Josh

GOOD, I have heard people say theses cacti can be a nuisance, but for the area I want to plant they would be great.

This is an area facing the road on my privacy fence. This area is narrow and hard to mow or do anything with including water so cacti should be a good addition.

It's it a set amount of area you could use sheets of the
weed-prevention carpeting, cutting out holes for your Opuntias' joints that you're rooting. It's a little time-and-labour intensive, but it will knock out the weeds and has the benefit of being green. Of course, there are drawbacks to this, mostly the expense and time, but we're spending your money, right?

Really, I'd think the weed barrier sheeting might be cheaper in the long run. Another thought is to sheet of certain areas around your cacti.

I don't believe roundup will kill the prickly pear cactus. Cactus and most other succulents have a waxy coating that doesn't allow them to lose water easily and thus doesn't allow stuff to penetrate their skin. I have used roundup on hens & chicks and sedums that got inundated with weeds. I tried not to get it on the hens & chicks but I know I did. Killed the weeds-didn't seem to hurt the hens& chicks. It may have stunted them a bit but they outgrew it. I was using the stronger stuff for poison ivy. I wouldn't do it more than once a year. Try a few plants--wait a week or so. See what happens. If they seem OK after a couple of weeks, do the rest. Happy Cacti!

I waited a few days for more legitimate answers to be proffered.

In the high deserts of the Great Basin there are waxy plants that RoundUP will not kill if used as directed, the liquid just beads up and rolls off.

wouldnt the round up also get in the soil an to the plants roots?

To kill prickly pear it is recommended that either undiluted glyphosate(Roundup) be injected into the flesh or else a spray of 1:10 dilution is used.

The dilution needed to kill weeds is far, far less than that. So you can spray away.

* Horrible things though, couldn't you use a nicer succulent/cactus than that?

Round up kinda killed mine. I say kinda 'cause it looked completely dead but months later it sprouted new pads.
(my prickly pear was the variegated kind, tho)

The dilution needed to kill weeds is far, far less than that. So you can spray away.

* Horrible things though, couldn't you use a nicer succulent/cactus than that?

Well they were FREE so that is why I choose them. I am trying to fill in an area between a privacy fence and the road. This is a narrow area hard to walk and weed so I plant on Cacti and Pampas grass and Yucca, Basically stuff that is no maintenance and you can't kill.

I find YUCCAs from time to time cut down on the side of the road and I grab them, I also got a few from my neighbor.

Thanks for the reply.

Prickly pear is an aquired taste. I am on my 35 variety of opuntia/cylindropuntia. There is no reason to shy away from them. They are not for the timid.

"There is no reason to shy away from them."

Well there are the glochids! ;) I was just thinking they're not the best plant to have if there's human traffic going by.

Occassionally at fruiting time I might overcome my timidity to get a few fruit, especially the red ones. Yum! It's a pity though - even they have glochids in them.

I used the standard dilution of Roundup about two weeks ago for a weed problem in my Opuntia/cactus bed. It didn't seem to harm the Cacti in the least. But the succulents are a different story.

Sedums don't like it. Sempervivums don't either. Didn't try it on the Orostachys but I assume being closely related to the others that it would finish them as well. Surprisingly, no damage on the Delosperma...but wouldn't say that's a 'go' either.

I used the standard Roundup. I would avoid the newer, "Extended Control" version.

Just my experiences...

Dave
Milwaukee

I have 2 acres full of prickly pair cactus and we had been getting lots of rain (that means millions of cactus but also weeds..tons of them) , I will be using glyphosate from DOW 1:200 lts. what could happen is that if I overspray and get the cactus wet it will mature early so it would be tiny but thick and yellowish instead of green but will not die.

Erik, not knowing your particular circumstances on the ground and in detail, but Opuntia (prickly pear) in general is known to be as tough as a West Texas steer and about as amenable to control. I'd guess you'd need at least two applications, but I'd check with your county agricultural department to see if they can offer any help.

There are plenty of great reasons to plant opuntia. The fruit is great, it has gotten out of vogue, but in th 40-50’s it was highly prized and sold for a nice price for growers. The pads are also good to eat but take a little work. Luther Burbank was so taken with the plant, its hardiness, rapid growth, very low cost to grow and high nutritional value, he spent may years planting it and trying to develop a thornless variety. He got close but never succeeded. He envisioned this plant to end world hunger. Besides the beautiful flowers and colorful fruit, the plant makes an incredible barrier for keeping people out. It is better than a fence when grown in. You are not going to climb this fence. When planted along an existing chainlink fence, only small creaturs will be able to pass. When thick it is also a great noise barrier. Any product that is made for weed control in beds of iceplant will not harm opuntia. Roundup is not recommend for use to kill cactus, but it will in a strong solution. Over spray of a solution of .8 to 1.6, which is recommended for almost all weeds would need to be actually applied to the cactus, wetting it all, to cause any severe damage, over spray at that level will have no effect. But when you have an established cacti bed, spray a pre-emergent, then you will only need to spot treat later for weeds.

David