Garden columnist Dan Gill answers readers' questions each week. To send a question, email Gill at dgill@agcenter.lsu.edu.
My mature and thick cast iron plants growing around the bottom of a tree have lots of brown edges and dead leaves. If I cut them down, will they grow back? I read that a hedge trimmer will easily cut them back, but I wanted to ask you first to prevent a possibly bad mistake. — Judy Hood
The drought last summer was hard on lots of plants. As tough as cast iron plants (Aspidistra elatior) are, they were affected — particularly those growing in spots that get some sun. You may cut the entire planting back to a couple of inches from the ground to remove the unattractive leaves. But check the planting for new growth first. If you see new leaves coming up, try to avoid cutting them back. After being cut back, cast iron plants will send up new foliage.
The first summer after cutting back like this, you will likely notice the plants are shorter and the planting is not as full. But by the second year, they will look like they did before. After cutting back, fertilize with a general-purpose fertilizer following packaged directions.
I’m growing a crop of large yellow onions, and they are looking good. What should I do with onions after I dig them up? Do I cut the greens off, or do I store them in my barn in onion bags with the greens attached? — Jason
When you harvest your onions, cut the tops off leaving about a 1-inch stub. When it is time to harvest the onions, the tops will turn yellow as the plants start going dormant. We generally harvest bulbing onions in late May. They will be fully developed and will store better if harvested then. You may store them in onion bags in the barn. But barns can get quite hot during the summer. Onions generally do better when stored at room temperature, such as you would find indoors, in a spot with good air circulation.
When watering potted plants, how much water is required? Do I need to water the whole surface or just the drip line and root zone? My potted plants have plenty of drainage, but I am trying not to waste water if possible. Also, when watering with a soluble fertilizer, how much should I apply to each pot? — Brandon Craig
It is best to add water to a container until water comes out of the drainage holes. That way you know you have wet the entire rootball. Generally, water the entire surface.
When you apply a soluble fertilizer, apply it as if you were watering the plant — until some runs out of the drainage holes.
Last summer, the cucumbers I planted were so bitter that we couldn’t eat them. Can you advise me on how to prevent this from happening this season? I have three hills and they are growing well. Rick
Cucumbers have been carefully bred to eliminate the chemical (cucurbitacin) that makes them bitter. Still, sometimes we get bitter fruit. The higher the level of cucurbitacin, the more bitter the cucumber will be. Bitterness is more common when the cucumbers are growing under stressful conditions, such as high temperatures and drought.
One way to avoid stressful growing conditions is early planting. Get seeds or plants into the ground in mid to late March through mid-April. That way you get your crop in before the stressful conditions of midsummer occur. Beyond that, just provide good care, including watering as needed during dry weather. There is no trick or secret to this.
This is a good time to plant tropicals like birds of paradise.
Garden tips
TO THE TROPICS: Now that the weather is getting warmer, it’s a great time to add tropical plants to the landscape, like tropical hibiscus, angel’s trumpet, bird of paradise, ixora, gingers, caladium, bananas, canna and split-leaf philodendron, to name a few.
GRASS TIME: Now is an excellent time to plant warm-season grasses such as St. Augustine, centipede, Bermuda and zoysia. This may be needed in many lawns damaged by the drought and/or the massive chinchbug outbreak last summer. Except for common Bermuda, solid sodding is the preferred method of establishing a lawn whenever possible. Although more expensive and labor-intensive at the beginning, solid sodding more than makes up for its advantages.
OUT WITH THE COOL: When cool-season bedding plants like pansies, violas, foxgloves, alyssum and dianthus begin to languish in the heat, pull them out (put them in your compost pile) and replace them with heat-tolerant summer bedding plants. Before replanting, remove all weeds that may have grown in the bed. Then spread a 2- or 3-inch layer of compost and a sprinkling of general-purpose fertilizer (follow package directions) over the bed. Thoroughly incorporate the compost and fertilizer into the bed and you are ready to plant. We expect vigorous plants and lots of flowers from these plants, and the effort you put into bed preparation will help this happen.
WATER WELL: As we move into summer, hot, dry weather will be more common. Be sure to pay attention to watering newly planted beds of bedding plants and vegetables. Also, check container plants growing on decks and patios often and water as needed. During extended dry periods, you may also need to irrigate established shrubs and lawns.