Pre-emergent won’t prevent privet

The large size of privet seeds helps them resist weed-preventer chemicals. WALTER REEVES

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The large size of privet seeds helps them resist weed-preventer chemicals. WALTER REEVES

Q: Will pre-emergent applied in March prevent privet seeds from germinating? George Ryals, Stone Mountain

A: Unfortunately, no. Weed-preventer chemicals are pretty good at preventing small seeds from developing into larger plants but they rarely affect the growth of large seeds. Privet seeds, the size of BBs, are not controlled by pre-emergent products.

Q: Chipmunks have chewed their way through my drip irrigation system. Is there anything that can be done? Ellen Blevins, email

A: This is a common problem. In my case, chipmunks or squirrels have three times chewed through a plastic water supply line that goes to my large fountain. They did a huge amount of damage to my garden water hose last year. There is no smell or taste repellent that could be permanently applied to plastic water lines to deter these creatures. I covered my exposed fountain supply line with wire mesh, which has worked fine so far. You could cut long 3-inch wide strips of wire mesh to cover your tubing and emitters, I suppose, but it would be a huge amount of work. You should also work to minimize the chipmunk population on your property. Take down your bird feeders in summer and consider installing a tall pole with a horizontal roost on top that hawks could use as a perch.

Q: I want to plant Gyoku-ryu mondo grass in a large shady space beneath trees. Any suggestions? Pam Williams, Gwinnett County

A: Common mondo grass, Ophiopogon japonicus, spreads easily from individual plants. But the variety you have chosen is extremely dwarf and spreads very slowly. I have a clump of it I planted five years ago that has expanded only an inch or two. Look for dwarf mondo grass, Ophiopogon japonicus 'Nana'. It grows a few inches taller than 'Gyoku-ryu' but spreads faster.

Q: I used half of a box of rock salt two years ago to kill a big pyracantha climbing up my home's wall. Has there been enough time to plant a tree near this same location? How long does it take rock salt to dissipate? Charlie Thompson, email

A: It all depends on how much moisture has come and gone from the site. Rainwater dissolves rock salt and moves it in whatever direction the water flows. There is no telling exactly where the salt concentration is now. One way to tell if the soil is still contaminated is to take separate samples of soil from spots near where you want to plant a tree. Put each sample in a small pot and plant a seedling vegetable in each one. If the plant leaves turn yellow after a few days, then the concentration of salt is too high for your tree. If you want to be perfectly safe, excavate the soil 3 feet wide and 1 foot deep in all directions from where the salt was poured. Replace the soil with high-quality topsoil and you can plant your tree with little worry.

Listen to Walter Reeves Saturday mornings on News 95.5 FM and AM750 WSB. Visit his website, www.walterreeves.com, follow him on Twitter @walterreeves, on Pinterest, or join his Facebook Fan Page at bit.ly/georgiagardener for more garden tips.