I’ve heard it said – and even said so myself in earlier years – that spring is short in Louisiana, with weather rapidly transitioning from winter to summer. But this really isn’t accurate.
If you look for and are aware of the signs, spring begins to show up in February in Louisiana, especially in the southern part of the state. By early March, signs of spring are popping out all over the state. Spring lingers through late April and even into early May. So, we actually have about eight weeks of spring weather – which is not so bad when you think about it. Whichever way you look at it, however, May is the first month of summer in Louisiana.
We will likely see a few more nighttime lows in the 50s or 60s in early May, but it won’t make that much difference. Summer temperatures, with nights in the 70s and daytime highs around 90, will begin to dominate our weather as we move through this month.
We and our gardens will endure these temperatures, along with the high humidity and high dew points that make them so very uncomfortable, until late September or October. In May, then, we begin to switch from spring gardening activities to summer gardening activities.
Things to do
Spring-flowering bulbs are reaching the end of their growing season. For those bulbs that will bloom again for us next year – many spring-flowering bulbs, such as tulips, are typically a one-time shot in our climate – you can begin to cut back the foliage. You don’t need to lift and store the bulbs out of the ground over summer, but make sure you don’t dig into the area and damage the bulbs accidentally. If you want to replant the area and the bulbs would be in the way, you may dig them up. Cut off the foliage and spread them out and let them dry for a few days or a week. Store the bulbs in paper bags indoors at room temperature, and replant in November.
Continue to plant warm-season bedding plants in empty beds or as you remove fading cool-season bedding plants like pansies. These summer plants will provide abundant color in flower beds and in containers and hanging baskets to brighten your landscape through the hot season. A few good choices include angelonia, begonia, balsam, melampodium, Profusion zinnias, pentas, blued daze, ornamental sweet potato, coleus, salvia, gomphrena, torenia and scaevola to name a few.
Tropical plants love the heat and humidity of Louisiana summers. They may not look their best in cold winter months, but many will return and grow. From May to November they provide colorful flowers, fragrance and bold foliage to our landscapes no matter how hot it gets. Because they thrive in high temperatures, this is an excellent time to plant your landscape with tropical plants, such as palms, gingers, elephant ears, philodendrons, hibiscuses, cannas and others.
Tropicals planted in early summer have the entire season to grow and settle in. This makes them better able to endure and survive the cold of winter. So this a good reason to plant tropicals earlier in summer rather than later.
Like tropical plants, lawn grasses love the heat and grow enthusiastically through the summer, as those of us who mow know all too well. This is a great time of year to lay sod to establish a new lawn or to repair areas where grass has been lost.
Mulching beds of flowers, shrubs or vegetables is our best defense against summer weeds. Make sure your beds have at least 1 inch of mulch around small plants, 2 inches around larger plants or shrubs and up to 4 inches around larger shrubs or trees.
Things not to do
Hotter days make transplanting plants far more risky. Small plants and tropicals can generally be carefully moved during summer, but most trees and shrubs should not be dug up and moved until the weather cools down in November.
Intense heat makes summer the most stressful time to plant hardy trees, shrubs and ground covers. The best planting time for these plants is the cool season – October through March. You may continue to plant them through the summer as long as they are grown in containers, but this is not the ideal time. Pay careful attention to proper watering.
Do not leave fading beds of cool-season bedding plants in place too long before you replace them with summer bedding plants. Well before the very last flower dies away, the bed will appear tired and less attractive and no longer fulfill the role of providing a beautiful accent to your landscape. Use your best judgment, but when your cool-season plants are obviously declining, it’s time to move on to warm-season plants.
Don’t forget to take higher temperatures into account. Working outside in especially hot weather places extra stresses on the body. Drink plenty of water before, during and after working in the garden, take frequent breaks and use sunscreen.
Dan Gill is a horticulturist with the LSU AgCenter. He can be reached at DGill@agcenter.lsu.edu