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 for them to properly produce fruit or flowers.
Landscapes around the state are in various stages of their spring awakening, but it is still February.
"With our unusually warm January and February, we're seeing flower buds opening and foliage growth commencing ahead of schedule," said LSU AgCenter horticulturist Allen Owings. Weather stations and meteorologists around the state reported average daily temperatures this winter have been considerably above normal. In addition, Louisiana has had fewer days below freezing than normal, and some areas south of the I-10/I-12 corridor have not yet had a freeze this winter.
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 for them to properly produce fruit or flowers. And they are below average statewide for this winter, Owings said.
"The most important months for chilling hours are November through February in Louisiana," Owings said. "And they 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 two to three weeks ahead of their normal flowering dates in some parts of the state. In addition, 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.
"We will see peak bloom earlier this year, and the significance of the peak bloom is less when we have warm winters that carry blooms over a longer period of time instead of over a concentrated period," Owings said.
Camellias have bloomed well this winter, and flower buds and open blooms have not been damaged by cold temperatures, he said. Indian hawthorns and other spring-flowering shrubs are showing some signs of not being dormant and are beginning spring growth.
"Plants that leaf out earlier than normal will be more susceptible to cold weather damage later this month and into March," Owings said.
Cool-season bedding plants that usually perform well during winter have been hampered by heavy rain in many areas of the state. Areas of south Louisiana saw 10 inches of rain in December and 20 inches of rain in January – and the rain has continued into February.
"Pansies and violas that are still looking good will last until mid- to late April in most landscapes," Owings said. "Flowering on some of the more traditional spring-flowering cool-season bedding plants, such as columbine, foxglove and dianthus, is ahead of schedule. Remove old flowers – deadhead them – to encourage secondary and repeat bloom."
Once again, monitor the 10-day forecast prior to planting warm-season bedding plants that are not frost-hardy, the horticulturist said.
But 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. Weeds are also way ahead of schedule in terms of seed germination and spring growth.
"Don't fertilize lawns too early," Owings warned. "This is always tempting. We may be able to fertilize a little earlier 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.
"Ideally, it is best to apply fertilizer and herbicide products separately as an alternative to weed-and-feed applications," Owings said. "This way, proper timing of the materials will optimize performance of both products."
Many people have asked questions about the mild winter weather and what problems or issues this is causing in landscapes, he said, but it is not a major concern.
"Weather patterns are highly variable, and plant performance is highly variable," Owings said. "Simply follow your usual practices and realize that many horticulture happenings in the landscape do not 'follow the calendar' from year to year.
"Variation occurs in the landscape, and we need to accept this and increase our horticultural knowledge to know what to do with our plants when weather patterns change."