Gardening and Horticulture - grass/weeds

I have a rose garden that has a white rock path and the rest is covered over with large pine bark nuggets. The entire area was tilled over and I laid down a cover of weed material before planting. The area had previously been patchy grass. My problem is that I still continue to get grass growing here and there, right through the weed material, bark and rocks. I have used chemical grass/weed killer, boiling water followed by an application of a mixture of vinegar and liquid soap - but it seems that once I conquer one area - the grass comes up in another and because of the bark and rocks it's difficult to see the small new grass coming up underneath - the grass in my yard is St Augustine and is thick bladed - any suggestions?

Hi EAP,

I'm not up on chemicals, but you mentioned you used weed killers. Have you tried Round Up or Finale?

Gami

Gami - I have tried RoundUp and K-Mart brand grass and weed killer (which I think works better than RoundUp) but the weeds die and then come back. They may kill the weeds but I really don't believe these kill the root. Actually, I think that my problem is more grass than weeds. It's funny,
if I was trying to grow grass - it would probably die and never come back!! Any other suggestions are welcome. Thanks

Hi EAP,

I'd have the same problem if I WAS trying to grow grass. :)

I suggest trying Finale. I've never used it, but some say it's better than Roundup. The only other thing I can think of is call a nursery or your county agent and tell them you are trying to get of St. Augustine grass and see what they recommend.

This site says it doesn't like high alkaline soils. This is a guess, but maybe putting lime on your path will do it in.

http://aggie-horticulture.tamu.edu/plantanswers/turf/publications/staug.html

You won't want to hear this, but it sounds like your landscape fabric has holes in it. It would be a job, but you COULD pull it all back up, spray weed killer on your grass and don't put down any kind of barrier until you're sure it's dead. It also sounds like you don't have enough mulch (rocks and pine bark nuggets) to keep it from popping through. I'm assuming you're talking about the white rocks that are fairly large. You could also try putting a layer of river rock on the fabric, then covering that with the larger rocks and pine bark.

I have an area that has nothing but black plastic and river rock, and the weeds haven't popped through in years. I didn't spray them first, just used a weed eater and cut them as close to the ground as I could.

Good luck and let us know what works.

Gami

Dear Gami - thanks for the additional advice and suggestions. I think that because the type of grass I have is very thick and coarse it pops right through the material. It's unbelievable to see the size of the holes that the grass creates pushing through. Maybe I should have used a plastic material instead. I do have quite a bit of pine bark chips and white river rock - but the grass always seems to find that one little opening!! I will look for Finale in the store - and in the meantime I bought a concentrate of Spectracide brand grass killer and an inexpensive sprayer and will try that first. I think I will go section by section and push aside the pine bark/rocks right down to the material and spray each area. Will let you know how it goes - thanks again - Happy 4th!

EAP,
Next time you make or redo a garden bed, you might want to consider killing all the grass/weeds before you till and cover. Some types of grasses/weeds (like the ones you have) aren't too badly affected by tilling because they come back from strong rhizomes, right through the mulch and all.

You can either use a chemical like Roundup (be sure to let it work for a week or two before starting) or you can lay some old plywood sheets down on the area for long enough to kill the weeds. Then you can till if you like or just cover with fabric and mulch.

I'll be honest, I don't use landscape fabric ever. Not because I think that it's bad, but because I think it's a waste of money. You have to mulch over it anyway, and it's cheaper for me to just lay the mulch really thick. The thick layer is great for keeping the soil moist, too. Mulch can be gotten cheaply (or free) from tree trimmers, power companies (who trim under lines), and landfills if they shred their limbs from pickup. Sometimes I do lay down old newspaper underneath, but it's for water savings, not weeds really. If you have killed the underlying weeds first, the fabric really won't add additonal protection because your only worry then is wind-blown seed, which can and will root in just the mulch. Of course, it's a lot less than if you just left the soil bare. The mulch breaks down over time and adds organic material to the soil. I don't like plastic mulch because it impedes water infiltrating the soil (even the ones that are supposed to let water in), and... well... it's plastic and I think we have way to much of it around anyway (even making it in the factory causes environmental problems).

Of course, none of this helps you right now, but might be food for thought if you make another bed. Good luck!

Hi All,

I just want to add that newspaper is great for killing weeds, adding organic matter to the soil and drawing earthworms.

I reworked a small bed by the driveway two years ago. I took out all my plants, added compost and manure and tilled. I put down 10 layers of newspaper and cedar mulch 4" thick. I didn't have any weeds. I should have. I know I pulled up a ton of weed seeds. I was surprised when I had to replace two plants this spring that only one or two layers of the newspaper are left.

I used the plastic as a barrier next to the house where mainly shrubs are planted with river rock on top. It's been in place for probably 15 years. I'd like to replace it with wood mulch, but for lack of time, I just haven't done it. I guess if something works, I don't worry about it.

I think black plastic under a walkway would be fine, but Leu's suggestion of killing the weeds first is the best way to go. Some things you learn the hard way and don't make the same mistake twice. It's almost more work to redo something than it is to do it right the first time and usually less expensive in the long run. Trust me, I know! :)

I used to think mulch was expensive, especially as much as I need to cover everything with 3-4". It didn't take long to realize that heavily mulched areas suppress the weeds, keep moisture in, and the time I spent weeding and watering was a big waste of time.

I've had a computer for three years. I've got numerous books on gardening, but I can't begin to tell you how much I've learned from folks like you. There are people on here and other garden boards with 50+ years of gardening experience and have made gardening so much more enjoyable. I've learned so much and keep learning every day.

Sooooooo, happy gardening to everyone and thanks for all the good advice. Let's keep sharing our good AND bad experiences, so everyone can learn by them. :)

Gami

leu: Thanks for all your input. I really thought that tilling and using a grass/weed killer before planting would work - but I'll know better next time. Thanks again

Gami: thanks again for your advice. I'm going to take the time to use the weed killer again and if necessary just keep up with pulling the weeds here and there. Thanks..