Vinca is a drought-tolerant bedding plant that requires lesser amounts of irrigation (Photo by Allen Owings) Watch terminal growth on roses for aphid populations and take control measures when necessary. (Photo by Allen Owings) News Release Distributed 05/02/14
By Allen Owings
LSU AgCenter horticulturist
HAMMOND, La. – May is here, and summer vacations and the end of the school year are approaching. But there is still much that can be done to improve your landscape plantings for summer.
Summer in the Louisiana landscape can actually start in May, even though the calendar says summer starts in late June. We have many activities to keep in mind during this four-to-five-month busy time of year in the home landscape. Keep all of the following items in mind to be more successful in your landscaping efforts.
Control thrips, aphids, cucumber beetles and spider mites on roses by using a recommended insecticide or miticide. We have seen an abundance of insect problems on roses so far this year, so monitor your plants and take care of harmful insect populations before their numbers increase. On roses susceptible to disease, continue blackspot control by using a recommended fungicide at seven- to 10-day intervals.
When irrigating this summer, water the soil area thoroughly. Try to irrigate less often, but irrigate well each time. Light, overhead sprinkling is not the best way to water. Ideally, landscapes perform best with 1 inch of rainfall or irrigation weekly.
Continue to plant warm-season bedding plants. Our spring Louisiana Super Plants (Luna hibiscus, Flutterby Petite Tutti Fruitti butterfly bush and Kauai torenia) are hot-weather survivors and can continue to be planted through summer.
You can still plant lantanas. They thrive in Louisiana’s hot summers. Try them in containers, too, where their drought tolerance is an advantage. Watch for lace bugs on lantanas. If your established plants aren’t performing well, prune and fertilize. Lantanas do best in full sun and need little to no irrigation. They are a great butterfly-gardening plant.
Dig and store gladiolus corms in a well-ventilated, freeze-proof place for planting next spring. Gladioluses perform well for us February through May. And summer is normally too hot and humid for gladiolus to perform well.
Plant sunflowers during late summer for fall flower arrangements. Flower colors include yellow, orange, red, bronze, white and combinations of these. It usually requires about 60 to 80 days from sowing seed until first flower color.
Prune azaleas no later than late June. Pruning azaleas after early to midsummer may remove next season’s developing flower buds. This applies to many spring-flowering shrubs as well as hydrangeas and gardenias.
During early summer, gardenias may have aphids, whiteflies and the associated black sooty mold. For optimum plant performance, control the insects with acephate, spinosad, imedicloprid or a summer horticultural oil spray.
Camellias and azaleas need care to set a good crop of flower buds for next year. Healthy, vigorous plants will set buds, but weak plants may not. If plants lack vigor, fertilize, provide moisture during stressful periods and control pests. Remember that these acid-loving plants may have problems if soils are too alkaline. Submit a soil sample to your parish LSU AgCenter office if you are unsure of your soil situation.
Louisiana irises are semi-dormant during late summer. Prune off seedpods and yellow or brown foliage to help keep the plants more attractive. You may transplant or divide Louisiana irises beginning in August.
Cut faded flowers from flowering annuals and perennials to encourage new growth and flowers. Old blooms and seed heads left on the plants can retard continued flower production.
These are just a few things to keep in mind as you garden over the next month or two. Summer months in the Louisiana landscape are some of the most colorful and productive if you give your plants proper care.
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.
Rick Bogren