How do I remove dandelions and bull thistle from my lawn?

Question

My backyard is completely (seriously, completely) infested with weeds -- bull thistles (or spear thistles) and dandelions (the common yellow-flower weed), to be specific.

_{Bull Thistle (source: Wikimedia commons)}

[ _Dandelion

How do I get rid of these things without the back-breaking effort of uprooting them all (there are probably too many), or the expense of paying a professional service for it?

I've heard vinegar works well (albeit it kills grass too), but I'd like to hear if there's another natural, inexpensive way to get rid of these nasty weeds.

Answer 1

Now that the question has been updated to include "Thistles" I've revised my below answer a little...

Credit for the "dandelion" part of this answer goes to my mum.

Dandelions:

When we (wife and I) moved into our current home 4 years ago, the front and back lawns were covered in dandelions (and other broadleaf weeds). I didn't want to go the herbicide route, and after speaking with my mum, she said the only way to truly get rid of (control) dandelions is to hand remove them (important: you need to remove root n' all) and recommended using a small hand garden trowel for doing so.

I didn't have a "small hand garden trowel", instead I bought a small (and cheapish) builders trowel and used that for 3 years:

Then last year on clearance (paid $1) I picked up a Fiskars Softouch Weeder:

Both of the above hand-tools have worked well in removing dandelions (roots included).

• The first three lawn cutting seasons I pulled a lot! of dandelions, at least once a week I would walk the lawns and hand remove all the unwanted plants I saw (all of them went into a plastic bag for offsite disposal).

• During last year's lawn cutting season I noticed a big drop-off in the number of unwanted plants I was removing, except for crabgrass (but that's a whole other story).

• This years lawn cutting season I've only had to remove a handful of "small" (young) dandelions, this is to be expected as I can't control dandelion seed heads blowing into my garden (though I wish I could).

• Yes, getting any unwanted plant under control via an "organic" approach is going to take patience and time, but if you stick with it, you will see (excellent) results.

  • And bare in mind, even if you go a "non-organic" route, you're pretty much "forced" to continually use the chosen method if you don't want to see the unwanted plant(s) return.

If you wish to read more about how I approach "organic" lawn care, go here on SE:

• What's an organic way to discourage crabgrass from a large "lawn"?

Thistles:

Personally I haven't had to deal with thistles in my lawn, that said I do occasionally have to deal with that unwanted plant (weed), along with dandelions and spurge in our street's common ground (flowering) areas that I maintain (I don't mow the grass, a lawn care company takes care of the mowing):

• Panicum Switchgrasses – Common Ground Areas

• Plants in Bloom – Common Ground Areas

• Gazebo Planting in Bloom

• Bottom Gazebo Repaired and New Plants Planted

• 2011: Common Ground Areas in Spring Bloom

I remove "smaller" thistles using the above tools, basically I treat its removal the same as dandelions ie Remove the unwanted plant, root n' all.

For "large" thistles I use a spade to dig them out (root n' all). After digging them out I back fill the holes with some suitable material and make good the area.

Good luck!

Answer 2

Whilst I share your preference for the non-chemical route, I think your best course, given that this is a serious infestation, is to spray the leaves with a systemic weedkiller, such as Roundup, which will spread into the roots and kill them. Make sure that the dandelions are growing actively - mid to late-spring is probably the best time - and that there is enough leaf area to spray the weeds fully. You will probably need to spray them at least twice.

Short of hand-weeding, an alternative natural strategy (although less effective than the chemical one) would be to spread corn gluten meal over the whole area, cover it with black plastic sheets and weight them down. This will deprive the weeds of water, and of light which will prevent photosynthesis, and will eventually kill most of them - but it will take some time.

Update:

I hadn't realized that the weeds were in your lawn, and I can understand why you wish to avoid using chemicals, given that you have young children. In the circumstances, hand-weeding would seem to be the only way forward; this tool has received excellent reviews and would take most of the backache out of the operation.

Answer 3

The weed&feed weedkillers are going to be insufficient for thistles, but should work on the dandelions. I think the thistle should be the priority though - it is spiky and looks bad.

Your options are physical removal or weedkiller: no free lunch, here! I would use a systemic "kill everything" weedkiller. You can use it as a spot treatment and if you get the thistles when they are still small, it is easy to apply to the crown without catching anything else nearby.

Yes this can pose a problem with kids, but you only need to ban them from the lawn for a week or so (read the instructions on the weedkiller). This should not be a problem if they are already refusing to walk on the lawn due to the spines. You could also try fencing off sections as you treat it?

Remove the dead thistles with a spade as the spines will still hurt. They should compost okay, but remove all seed heads and trash them (do this before the weedkiller as the seeds will only spread).