Spring is a time of beautiful blooms and gorgeous greens. But it is also a time when those dreaded weeds make themselves known, too. Master Gardener Volunteers of Cobb County members Joy Chanin and JoAnne Newman answer some of the most common questions about our native weeds, how to spot them and how to rid them of our yards and gardens.
What phone apps are available for weed identification?
• EDDMaps (invasive tracker app)
• Picture This: Apple app free or cost for premium+ services for iPhones and iPads only
• Plant Snap: Apple only – free or cost for premium+ services
• Pl@ntNet: Apple, Google Play or online
• Google Lens App from Google Play, also works
on Android phones
• iNaturalist App from Google Play works on
Android phones as well
Where can you purchase horticultural vinegar?
JoAnne did a quick search – looks like you can buy online and at some “Big Box” stores. Check with your local hardware and garden supply stores as well.
Tips on using hot water as a weed killer:
Hot water and any contact herbicides need to be used ONLY on the plants that you want to kill. You must be careful with boiling water, as it will kill roots on plants like nearby, desirable plants.
I have what I believe is privet, or Chinese privet. The birds and bees seem to like it, with some bird nests. Isn’t privet invasive? Should I remove it?
YES! Chinese privet (Ligustrum Sienese) is extremely invasive in our area. As Cobb Master Gardener Becky Blades put it: “Never leave privet for the birds!”
My privet with nests (NOTE: we assumed birds nests) is blocking where I want to grow a food garden, but I don’t want to disturb pollinators. I don’t have many sunny spots to work with.
The best solution for this situation is to remove the privet when the birds have left the nest, establish your vegetable garden and surround it with native and non-invasive pollinator plants! Here is a list of great substitutes that make the birds, bees, vegetables and Mother Nature happy!
I have too much blue grass (poa annua). Other than herbicide, any ideas to remove?
Annual bluegrass can produce 2,000 seeds per plant. It is easy plant to pull if you start as soon as you see any growing. It is a winter weed, which can be seen from September/October through May. Conditions that are favorable for annual bluegrass may include compacted soil, high fertility soil, moist fertile soil, poorly drained soil or too much shade. Annual bluegrass seeds can sprout as low as ½ inch above the ground. pre- and Post emergent treatment can help in controlling it.
How do you best get rid of Smilax (Greenbriar)?
The rhizomes of smilax are often found buried deep in the soil and are difficult to find and remove. The two recommended methods are digging out the rhizome or, if not possible, cutting the vine within a few inches of the ground and, while the cut is fresh and wearing gloves, paint the cut vine with a vine killer. As Becky Blades points out in her yard, it is often easiest spotted in the winter, when leaves are off the trees and the vines are seen up the trunks and among the branches (unless you literally run into it – ouch)!
I have creeping Charlie all over my yard, about a half acre. Is there any way to get it out besides pulling or chemical assault? I live on the Yellow River and am concerned about run off.
While hand removal is best when working around your desired plants, this weed can be treated with herbicides containing Dicamba. Just remember, we are in a warmer climate zone, so applications of any herbicide will vary. If it is taking over your lawn, it’s best to build a healthy lawn and get this weed out of your grass!
Moral to the story: Read the LABEL and carefully follow the instructions with this or any other chemical.
I have a real problem with oxalis. I even see it sold in stores, but it is almost impossible to kill when it is within other plants.
Maybe this is why we love it in pots! As one of our participants pointed out, the plant grows from rhizomes. They kind of look like pineapples or pine cones. Like all weeds, you need to be sure to dig up the entire root system to assure that they won’t grow back.
What do you suggest for killing clover or, a.k.a., Wood Sorrel?
Wood sorrel is another name for the oxalis plant. Small plants can easily be handpicked or dug as they appear before they flower or form seed. Removal of all vegetative portions of the plant, including roots and rhizomes, is important. Rhizomes can be easily removed when soil is moist. Do not place the weeds with seeds in compost bins for reuse in the landscape. A light layer of mulch in landscape beds and around flowers and shrubs will aid in preventing further germination of oxalis seeds. The seeds require light for germination, so limiting light to the seedbed with mulch will reduce the numbers of new oxalis plants. Maintenance of healthy, dense lawns will create less space for oxalis to invade. Lawn maintenance should adhere to fertilizer and lime recommendations obtained from soil test results combined with proper mowing height and frequency requirements.
I somehow have onions growing in my yard. How to get rid of them?
All are members of the allium family and are similarly treated. How do you know the difference? Snip and smell. Wild garlic is particularly problematic in lawns. They become a mass of tiny bulbs that are very stable underground and either need to be completely removed, constantly trimmed back (just to annoy them) or chemically treated.
What is the best way to get rid of spotted spurge? It grows in my yard and cracks in my sidewalk constantly.
In an area that you never intend to grow desirable plants, you can use horticultural vinegar, boiled water or an herbicide. It is hard to get out the roots in concrete cracks. When it grows in your garden beds or lawn, you can try to hand pull them, but be careful to get the entire plant, root and seeds. All spurges reproduce by seed, and creeping spurge also can produce roots along the stem, creating new plants. Presence of spurge can indicate possible nematode infestation or compacted soil. When spurge is wet, the seeds will stick to things like the bottom of your shoes or animal fur. Prevent an infestation by removing the weed from your landscape before it begins to produce seed. Feed your lawn regularly and mow it at the proper height to help keep the turf full and dense to ensure that this non-competitive plant won’t have room to grow.
I have Nandina shrubs, but I keep seeing that it’s an invasive plant. Are there some Nandinas that are not?
Yes, there are some that do not produce berries and therefore are less invasive.
Our fellow Master Gardeners weighed in on this question well, for those whose do produce berries:
You can use Nandina berries for Christmas decorations. I still have a bunch outside to cut and dispose of.
May I suggest that if you have Nandina, you remove the fruits … the prettiest part!
I remove the white flowers in the spring that become the fruit. That way I know I am not risking the berries spreading; additionally, the berries have been found harmful to the birds that eat them.
From JoAnne: I recently dug up some Harbor Dwarf Nandina in my yard that overgrew the space. It is sold as a groundcover and rightly so! It spread and was very difficult to dig up. I am going to plant something native in its place.
What weed do we underestimate in Georgia that has medicinal or other purposes that we should look at encouraging?
Great question! Green Meadows Preserve is home to the Cherokee Garden, a project of the Master Gardener Volunteers of Cobb County. It contains plants that the Native Cherokee used for both medicinal and culinary purposes. You can learn about the garden on our website or visit Project Chair Tony Harris’ website at mycherokeegarden.com. Better yet, make a field trip!
How do I get rid of plantain weeds?
Hand-pulling is most practical for small areas. To prevent plantains from invading your lawn, improve the health and density of the lawn by fertilizing at the right time with the correct amount, maintaining appropriate soil pH, mowing at the correct height and watering properly. Depending on the type of lawn you have, post-emergents may be effective. In ornamental beds, apply 2-3 inches of mulch to prevent sunlight from germinating the seeds.
About Master Gardener Volunteers of Cobb County:
The Master Gardener Volunteers of Cobb County (MGVOCC) supports the University of Georgia Cooperative Extension Service and strives to improve the quality of life in our community by delivering research – based horticultural information, educational programs and projects.
• Started in 1980
• Members trained and certified by the University of Georgia
• More than 250 active members
• Support 58 school and 16 community and demonstration gardens
• More than 21,000 hours volunteered on average each year
For more information, visit cobbmastergardeners.com or contact the UGA Cooperative Extension Service office at (770) 528-4070 or 678 South Cobb Drive, Suite 200, Marietta, GA 30060.
18th Annual Garden Tour
The Master Gardener Volunteers of Cobb County, Inc.’s 18th Annual Garden Tour is scheduled for Saturday, May 22, 2021 from 10 a.m. to 5 p.m. and will feature five gardens, including four private gardens and the Reconnecting Our Roots Community Garden, all in the central and east Cobb areas.
Tickets are now on sale and are $15 in advance or $20 on the day of the tour. Children ages 17 and under can attend for free. The tour is held rain or shine, and masks are required.
For more information or to purchase tickets, visit cobbmastergardeners.com.