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Some yellow irises are an invasive species. You can distinguish them by feeling the leaves for the prominent veins that are present in yellow flag leaves but not in yellow Louisiana iris leaves.

Garden columnist Dan Gill answers readers' questions each week. To send a question, email Gill at  

It was always my understanding that the common yellow iris with a raised vein along the center of each leaf was not a Louisiana iris, and it would overtake other irises if planted together. They are very aggressive. Not so? — Faye

Yes, it is true that the yellow flag (Iris pseudacorus), which is native to Europe, is used as an ornamental here and blooms with yellow flowers. Like Louisiana irises, they enjoy growing in wet areas, like around a pond, or in garden beds. However, it is unsuitable to combine with Louisiana irises since it is a more vigorous grower and will often crowd them out. It can also be invasive and should not be planted near natural areas where it might spread.

That said, you may be responding to the part of my column last week where I listed the colors that hybrid Louisiana irises come in. There are yellow varieties of the Louisiana iris. So, an iris blooming yellow does not automatically mean it is not a Louisiana iris. As you mention, you can distinguish them by feeling the leaves for the prominent veins that are present in yellow flag leaves but not in yellow Louisiana iris leaves.


Gary Salathe, of the Louisiana Iris Conservation Initiative, explains what invasive yellow iris looks like. Note the prominent vein in the leaves.

I am writing this question on behalf of my dad, who has gardened for many years. He moved to Metairie in 2020 and planted some orange trees. He is wondering how to get a soil sample test so he can determine if he needs to change anything in regard to these trees. They are not producing fruit (quite unlike the many trees he had planted when he lived in Houma).?If you could direct me on how to get info on the procedure for testing the soil, I would greatly appreciate it. — Sloan

He can get his soil tested through the LSU AgCenter. Contact the Jefferson Parish LSU AgCenter Extension office about getting a soil test kit to submit soil samples.?Some nurseries may have the soil test boxes available as well.??

But this may not be necessary though. The soil in Metairie is just fine for growing citrus trees. You see them in yards all over the parish. The main issue is likely the age of the trees. Citrus trees need time to settle in and mature after planting before we expect them to begin regular production of fruit.

During the first four to six years after planting in the ground, citrus trees typically produce fruit erratically or not at all. His trees were planted in 2020. This is likely why your dad’s trees have not been producing. This is not related to a problem with the soil. Time and good care will take care of this.

I have a compost pile I started a few months ago. I’m new to this and became worried when I saw what appeared to be various molds or fungi growing in the compost material. Should I be concerned? I don’t want to introduce diseases into my beds when I use the compost later on. — Geri

You should not be concerned. The fungi you see growing in the decaying organic matter are decomposing the organic matter and, along with bacteria, converting it to compost. You need them in the pile. They are considered safe and beneficial.

These fungi use dead plant tissue for food and do not attack living plants. They will not hurt or damage your landscape plants. Indeed, when incorporated into the soil of a bed, the beneficial fungi in the compost can suppress pathogenic fungi in the soil to the benefit of plants.

So, the organic matter you added to the compost pile is breaking down, and as that happens the beneficial fungi carrying out the process will become visible from time to time. There is absolutely no need to be concerned about this. What you are seeing are the "good guys" that will help make your soil healthier and your garden grow better when you use the compost.

Sprouting corn (copy)

Corn is among the many vegetables that can be planted now.

Garden tips

PLANT NOW: Vegetables to plant in April include cantaloupe, collards, corn, cucumber, cucuzza, cushaw, eggplant, honeydew, lima beans, luffa, Malabar spinach, mirliton (plant sprouted fruit), okra, peppers (sweet and hot), pumpkin, snap beans, Southern peas, squash, sweet potato (plant rooted cuttings) and watermelon. In early April plant transplants of tomato, bell peppers and Swiss chard.

MULCH: Be sure to mulch newly planted beds of shrubs, vegetable transplants or bedding plants with a two-inch layer of leaves, pine straw, pine bark or other materials to control weeds, conserve moisture and keep the soil from packing down.

LILIES BEYOND Easter: Don’t throw away your Easter lilies when they finish blooming. Trim off the top of the plant where the flowers bloomed – do not remove any green foliage. Remove the plant from the pot and plant it into a well-prepared bed enriched with compost. Choose a location that receives sun with some shade in the afternoon. Plant so that the top of the rootball is even with or slightly below the soil surface and water in. They will bloom in the spring year after year.

CALADIUMS NOW: Plant caladium tubers or started plants in the garden this month through June. Caladiums are excellent for shady areas and combine beautifully with ferns, begonias, torenia, liriope, impatiens, hosta and coleus.

THE END OF TULIPS: Treat tulips as annuals and remove the whole plant when they finish flowering since they will not rebloom again next year in our climate. Chop up the foliage and bulbs and add them to your compost pile.

Dan Gill is a retired consumer horticulture specialist with the LSU AgCenter. He hosts the “Garden Show” on WWL-AM Saturdays at 9 a.m. Email gardening questions to