If you can block light from that weeded area for 3 or more weeks, that would be enough to kill off any existing weed roots. However that won't prevent new weeds from growing on the mulch itself.

Your plan to heavily mulch the area is on the right track, I however will advise you to add landscape fabric layer which is pinned down with long nails & washer. Then top mulch it. What this does is not only to prevent light of reaching the plants, but also to prevent new weeds from penetrating the mulch into the ground below.

I also take it that you are concerned that underground roots might appear elsewhere in the yard. I think the weeds you described propagate by seeds, but if that is indeed a concern, perhaps applying an edger or a barrier would work.

ianna

The "politically incorrect" receipe:
Avoid cutting or mowing plants.
Apply Roundup on foliage.
Let stand for a week.
Repeat application if necessary - and let stand for another week.
Apply layer of mulch, at least 3" - 4" thick.

Thank you both for your suggestions. I was ready to dig up everything and just put a lawn but then last night I started to clean up a little bit even though I know that in a week or so, I'll just have a whole bunch of new weeds. I've already bought several bottles of vinegar so I may try that on a few areas that have nothing on them. Thank you so much for your suggestions. It's just frustrating when you can't control certain things in your life and this is something that nature wins all the time so I just have to adjust my thinking a little bit.

You didn't say what you did for the first five years-- did you use mulch? Mulch prevents weed seeds from germinating.

Ianna is right about blocking light but if you plan to plant again, do not use landscape fabric. Fabric is good under pathways and shrubs, but you can't plant anything once it is in place.

To kill the weeds, mow them to about 2 inches high and place 5-6 layers of newspaper over the area, moisten lightly and cover with mulch. Wait about 6 weeks and then the weeds will be dead. You can then cut through the mulch and newspaper and plant.

You will need to check the area for weed seedlings weekly and remove any. Its either mow or weed, no landscape is maintenance free.

Hi Judy,

I have used landscape fabrics in garden beds because it does produce a nice lean look. In a very similar technique as you described for newspaper mulching, I would also simply cut a large hole through the landscape fabric to allow for plant growth. The added advantage is that the fabric will continue to prevent weed growth for a much longer period than newspaper. I've used this technique for years.

In fact, I have just returned from a trip from the States where I've seen this technique used mostly in open mall areas.

Ianna