Blooms of saucer magnolias (Magnolia soulangiana) are a highlight of the late-winter landscape. (Photo by Allen Owings)

Azaleas typically reach peak bloom in Louisiana in late March and early April. (Photo by Allen Owings)

News Release Distributed 02/20/15

By Allen Owings
LSU AgCenter horticulturist

HAMMOND, La. – Landscapes around the state are in various stages of their spring awakening, but it’s still February.

So far Louisiana has had an average winter, although two to three cold snaps have pushed temperatures to the mid- and upper teens in locations that normally experience only low 20s in an average year. Chilling hour accumulations are slightly higher than average with ranges from 600 to 900 hours statewide.

During the dormant season, many fruit trees and some landscape plants require a certain number of chilling hours – the amount of time when temperatures are below 45 degrees – in order to properly produce fruit or flowers. The most important months for chilling hours in Louisiana are November through February. Chilling hours are offset by the times when temperatures are above 70 degrees.

Many mid- to late winter-flowering trees – such as ornamental cherries, Oriental magnolias, swamp red maples and more – are blooming now, especially in south and central Louisiana. This is about the normal flowering time for most of these plants. Azaleas in south Louisiana began showing signs of bloom-opening in January. Normal peak bloom for many of the Indica-type azaleas in south Louisiana is March 20-25. And Indian hawthorns and liriope are showing their spring foliage flush.

Plants that leaf out in February and early March are more susceptible to cold-weather damage that may still come during late winter.

Pansies and violas that are still looking good will last until mid- to late April in most landscapes. Flowering on some of the more traditional spring-flowering cool-season bedding plants, such as columbine, foxglove and dianthus, is on time, and plants have handled the winter growing conditions well across much of the state.

As we approach the end of winter and the beginning of spring, monitor the 10-day forecast prior to planting warm-season bedding plants that are not frost-hardy. Gardeners can continue planting frost-hardy bedding plants, such as petunias and snapdragons, through March.

Depending on where you are in Louisiana, lawns are in various stages of spring green-up. Warm-season weeds are now germinating and beginning to grow, and cool-season weeds are getting larger and are setting seed.

Don’t fertilize lawns too early, although this is always tempting. We may be able to fertilize a little earlier than usual this spring, but check the 10-day forecast for frost and freeze possibilities prior to application.

During most years, the LSU AgCenter recommends the following times for first fertilizer or weed-and-feed applications on St. Augustine and centipede lawns:

–New Orleans – mid- to late March.

–Baton Rouge/Lake Charles/Lafayette – late March or early April.

–Alexandria – early April.

–Monroe/Ruston/Shreveport – mid-April.

Ideally, it is best to apply fertilizer and herbicide products separately as an alternative to weed-and-feed applications. This way, proper timing of the materials will optimize performance of both products.

Many people ask about winter weather each year regarding whether it was colder than normal or average. Weather patterns are highly variable, which make plant performance highly variable. Simply follow your usual practices and realize that many horticulture happenings in the landscape do not follow the calendar from year to year. Knowing frost dates, recommended planting times and winter or summer hardiness of your landscape plants are keys to successful gardening.

You can see more about work being done in landscape horticulture by visiting the LSU AgCenter Hammond Research Station website. Also, like us on Facebook. You can find an abundance of landscape information for both home gardeners and industry professionals at both sites.