Garden columnist Dan Gill answers readers' questions each week. To send a question, email Gill at dgill@agcenter.lsu.edu.
I have a bougainvillea, and yesterday I noticed something has been eating holes in the leaves. This happened before and I thought it was snails, so I put the beer traps out but caught nothing, and the chewing went on. — David
The problem with the bougainvillea is caterpillars. You may not see them, but you certainly can see the damage they are causing. Look over the plant carefully and you will likely find the caterpillars. Pick them off and dispose of them. You may also spray the plant with spinosad as soon as you see damage occurring to control the caterpillars and minimize damage. Treat again anytime new damage begins to occur.?
Last spring, we had a terrible time with stickers in our lawn. I was concerned about my pets and children playing on the lawn. I have heard that there is something we can do in fall to help prevent this weed from being such a problem. Do you have any information on this? — Diane
Burweed or sticker weed (Soliva pterosperma) is a cool-season weed that germinates in the early fall as temperatures cool and grows over the winter. It flowers and produces seed pods in the spring. It is the seed pods that cause problems, as they are spiny. The spines on the pods can painfully puncture feet when walked on barefooted. Once the spiny seed pods have formed, there is nothing you can do to alleviate the problem.
A two-prong approach will work best when controlling burweed or sticker weed. The first effort is preemptive and involves the use of a preemergence herbicide or weed preventer. A preemergence herbicide is applied before the seeds start germinating in the fall, and it kills the seeds as they germinate. Early application before seeds germinate is critical. Apply the preemergence herbicide the first week in October following label directions. Look for products such as Sta-Green Crab-Ex, Green Light Crabgrass Preventer 2, Hi-Yield Turf and Ornamental Weed and Grass Stopper, Scotts Halts and other brands at your local nursery (ask the staff to help you select the proper product). That’s the first line of attack.
Then, look over your lawn very carefully in January and February. If you see any young plants that managed to get by the preemergence herbicide application, spray the lawn with a lawn weed killer like Weed B Gon, Weed Free Zone, Atrazine or other brands of lawn weed killers at your local nursery. If needed, you could make a second application following label directions. That’s your second line of attack.?
I plan to enlarge some landscape beds and install some new areas so that I can plant in October. The new areas are covered by lawn grass. I’m considering using the “lasagna garden” method using cardboard boxes and newspaper to smother the grass and then covering that will layers of green and brown organic matter. I have lots of ideas for the brown layers but need help with the green layers. I don’t have grass clippings available, and we don’t save fruit and veggie scraps. Is there anything I can purchase that would serve this purpose, such as bagged compost or blood meal? Other ideas? — Adam
Bagged compost is a good substitute for green material, as is bagged manure. You may use both. Sprinkling a nitrogen source, like blood meal, over brown materials adds nitrogen to them, making them decay more rapidly/reliably. So, blood meal also can work if green organic matter is lacking. Adding it to brown material adds nitrogen, changes the nitrogen to carbon ratio and essentially turns the brown material into green material.?
Plant carrots in September.?
Garden tips
PLANT YOUR VEGGIES: Vegetables to plant in September include transplants or seeds of broccoli, cabbage, cauliflower, Chinese cabbage, collards, English and snow peas, Irish potatoes (plant small, whole potatoes saved from the spring crop), kale, kohlrabi, leek, lettuce, mustard, onion, shallots (plant small bulbs) and Swiss chard. Plant seeds of snap beans, beets, carrots, radish, rutabagas and turnips. It’s getting late, but plant tomato and bell pepper transplants this weekend if you haven’t already.?
HERBS NOW: Herbs to plant in September include transplants of basil, sage, rosemary, thyme, oregano, chives, lavender, Mexican tarragon and mints. Plant seeds or transplants of dill, parsley, fennel, cilantro, arugula, borage, chamomile and chervil.?
IN THE DARK: Make sure poinsettias in pots or in the ground in your landscape do not receive artificial light at night from nearby flood lights, porch lights or streetlights from now on. Light at night can prevent them from blooming.
ROSE CARE: Repeat-flowering roses, such as hybrid teas, grandifloras, Chinas, Bourbons, teas, floribundas and landscape roses (such as Knock Out and Drift roses) should be cut back by about one-third now. This prepares them for the fall blooming season. Pruning controls size, removes dead wood and stimulates vigorous new growth that will produce lots of flowers. Fertilize after pruning.
FOR KIDS, TOO: If you want your kids to work in the garden, it’s a good idea to purchase gardening tools specially made for them and properly sized for them to use. This gives kids a chance to identify with gardening more closely because they have their own tools. It’s safer, too.