Garden columnist Dan Gill answers readers’ questions each week. To send a question, email Gill at email@example.com.
I planted several 3-foot-tall Natchez multitrunk crape myrtles last spring. I’m not sure how to prune and when to prune them for best effect. Can you help me? —Oliver Prejean
Don’t do any pruning for the first couple of years after planting. After that, promptly remove any suckers that form at the base of the trunks. Over the next five or 10 years, gradually remove lower limbs as the trees grow taller to raise the canopy to the desired height. While doing this, maintain about one-half trunk to one-half leafy canopy. That is, don’t remove too many lower branches each year.
Watch for crossed, rubbing branches and prune to correct that. Basically, as the trees grow, guide their growth in ways that enhance their natural form but address any problems that need to be corrected. Pruning can be done at any time, but major pruning is generally done in late winter or early spring before they leaf out.
What can I do for a bed of liriope overrun by weeds? I have weeded out all I could, but there is a grass that grows by rhizomes in this bed that I haven’t been able to control. It’s not torpedograss or any of the common grasses that I know about. It’s almost like a reed but very small. I have used Over the Top and Preen to help with other weeds, but those herbicides haven’t controlled this one. — Bonita Garcia
Over the Top is a postemergence selective herbicide containing sethoxydim that is useful in controlling grassy weeds in beds and in ground-cover areas. If it controls the grassy weeds but not this particular one, it is likely not a grass. There is a good chance that it is actually a sedge. Sedges look like grasses but are a different group of plants and are not controlled with selective grass killers like sethoxydim or fluazifop.
The herbicide Image Kills Nutsedge with imazaquin can be used to control sedges, and it is safe to use on liriope. If the weed you are dealing with is a sedge, several applications should greatly reduce the population. Still, it is important for you to properly identify the weed to make sure you use a product that has a chance of controlling it. Contact your parish LSU AgCenter Extension office for help with this, or take some of the weed to nurseries for ID.
I planted bell pepper seeds last spring that seemed a little slow developing but grew into healthy plants. However, they did not bear any fruit although there were plenty of blossoms. I was preparing to plant my fall vegetables and decided I might as well give up hope and pull up the peppers. Luckily, I noticed little peppers on the plants before I yanked them. Do you have any idea why they would produce now but not at all during the summer? —David Arceneaux
Bell peppers are sensitive to intense heat and tend to drop their flowers during the hottest part of summer. To grow bell peppers from seeds, you need to start the seeds in January or early February (in greenhouses or under plant lights) to produce transplants ready to go out in mid-March to early April. Or purchase transplants at the nursery at that time and plant them.
Our main bell pepper harvesting season is in early summer to midsummer from flowers that set before it gets too hot — major harvest in late May, June, maybe into early July. Plants will produce little during the summer, and peppers that are produced are generally of low quality.
This does not apply to hot peppers or other types of sweet peppers that tend to produce well during summer.
If you keep the bell pepper plants in good shape through the summer, they will begin to set fruit again as the weather cools and will continue to produce bell peppers through the fall season until the first hard freeze.
GROWING STRAWBERRIES: Purchase and plant strawberry plants this month in your vegetable gardens (or even in flower beds) in full sun with good drainage. It is best to plant strawberries in raised beds or raised rows. After planting, be sure to mulch the plants with a couple of inches of pine straw. Recommended varieties are Festival, Camarosa, Camino Real and Chandler.
MOVING TIME: Gardeners often place their tropical plants in containers outside for the summer and bring them indoors during winter. Move any plants you intend to winter indoors to very shady areas outside, such as under carports or trees, for the next three or four weeks. This will allow them to adjust to lower light intensities before you bring them inside where light is more limited. Make sure you place plants in front of bright windows when you bring them indoors.
RADISHES FROM SEEDS: Plant a crop of radish seeds in the garden now for harvesting around Thanksgiving. Once the seeds come up, make sure you thin the plants to a spacing of 2 inches apart. Otherwise, the roots will not develop properly.
FEED AND WATER: As the weather cools, we will be planting colorful cool-season bedding plants. After planting, water them in with a soluble fertilizer to get them off to a good start. Use a hose-end applicator that automatically proportions the fertilizer in the water as you apply it. Repeat the soluble fertilizer application every 10 days until the plants begin to grow well.