LSU AgCenter Horticulturist
I say it each fall: This is an excellent time of year to work in the landscape. The weather is cooling, and the days are getting shorter.
If you want to add to your landscape, now is a great time to plant cool-season annuals, perennials, trees and shrubs. Luckily, there are many fall plant sales going on all throughout the state. Check your local newspapers and the LSU AgCenter website for dates and times.
A few of the highlights include the LSU AgCenter Hammond Research Station fall festival and plant sale Oct. 8; Pelican Greenhouse’s sale at New Orleans City Park Oct. 8 and 9; Plant Fest at Hilltop Arboretum in Baton Rouge Oct. 15; the Folsom Fall Garden Festival Oct. 29; and the LSU Horticulture Club fall plant sale Nov. 18 at the corner of Highland Road and South Stadium on the LSU campus.
In addition to fall festivals and garden shows, one of the other great things this season provides is fallen leaves. You can improve your soil by incorporating those leaves. They can provide valuable organic matter and minerals to your soil. Decayed plant materials contain carbon (C), oxygen (O), hydrogen (H), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) as well as other nutrients in smaller amounts.
All of these nutrients are key to soil fertility and plant health. Microorganisms also are an active organic portion of soils, making up 10% to 40% of the organic matter. Soils, in fact, are alive. In 1 tablespoon of soil, there more organisms than there are people here on Earth.
In addition, there are roughly 5,000 different types of bacteria in 1 gram of soil, from which nearly all antibiotics are made. One other cool fact about soil is that 10% of the world’s carbon dioxide emissions are stored in soil.
I’ve mentioned before how home gardeners can help improve the environment and combat the climate crisis by planting trees to help remove greenhouse gases such as carbon dioxide. But now you know that soils can be a carbon “sink” that absorbs CO2 from the atmosphere as well.
By leaving fallen leaves on the ground, you provide materials for earthworms to break down and shelter for insects such as butterflies and moths, who overwinter in leaf litter. According to the National Wildlife Federation, many bird species forage in the leaf layer too, searching for insects and other invertebrates to eat, including wood thrushes, towhees, robins, sparrows, common yellowthroats, bobwhites and wild turkeys. Even some bat species overwinter in the leaf layer.
Chop or shred leaves to make it easier for worms and beneficial microorganisms such as fungi and bacteria to break down the leaves. Leaves can be composted first to make leaf mold, or you can work the leaf mold into the top several inches of the soil in autumn. In addition, chopped leaves can be used as a winter mulch on top of garden beds to help retain moisture, reduce weeds and insulate roots from cold temperatures.
So, get out there and plant something. Also remember that October is traditionally the driest month of the year in Louisiana. Make sure trees and shrubs are receiving enough water so that they do not become stressed and more susceptible to disease and insects.
But you can be a lazy gardener when it comes to the leaves. Just leave them.
Fallen leaves can be raked and used as mulch in landscape beds and gardens or composted. LSU AgCenter file photo
Fallen leaves provide shelter for many butterfly and moth species. LSU AgCenter file photo
Look for fall plant sales and festivities. LSU AgCenter file photo