May is the month for when landscapers and homeowners are rewarded for their spring efforts with lush beauty and the promise of a glorious summer. Jason Reeves, curator of the University of Tennessee Gardens, Jackson, took some time from working in the Gardens to offer these tips for keeping your landscape and gardens beautiful and productive:
• Plant butterfly weed (Asclepias), parsley, dill, rue and pipevine to encourage butterflies in your garden. The foliage of these plants provides food for the caterpillars. Aristolochia fimbriata is a lovely ground-cover-type of pipevine that is covered each year by the pipevine swallowtail caterpillar at the UT Gardens, Jackson. It may be a little hard to find for sale, but it is worth seeking out.
• Early May is a good time to cut back bushy woody perennials, like rosemary, rue, lavender, Santolina and Artemisia.
• If you haven’t done so already, prune spring-flowering shrubs (azaleas, flowering quince, Forsythia and Loropetalum), but only if they need it. To keep their forms more natural in appearance, as opposed to looking like a meatball, follow the taller branches down into the shrub and cut just above a joint.
• A good option for Loropetalums that have outgrown their space is to prune them into a tree-form. They easily can be limbed up by removing lower branches. Loropetalum ‘Crimson Fire’ is a dwarf form that has proven to be hard in all but the coldest part of Tennessee. As with all Loropetalums, they are best planted in spring or summer in insure proper establishment before the winter months. It will mature to 3-ft tall, and can be seen growing at the UT Gardens in both Knoxville and Jackson.
• Remove the flowering stalks on yucca as they begin to form if you dislike the look of the bloom. Cut them off down in the foliage at the source, and you won’t even know they were there.
• Old flower stems can be removed from lungwort so not to distract from the lovely foliage.
• Caladiums and vinca need warm soil. Caladium tubers will rot in cool soil, and vinca will be disease-prone, or exhibit stunted growth. Night temperatures should regularly be above 60 degrees F before planting them.
• You can still direct seed easy-to-grow flowering annuals and vegetables. Some easy flowers to grow from seed include marigold, zinnia, sunflowers and cosmos. Beans, peas, corn and okra are some easy direct sow vegetables, while dill, basil and cilantro are some easy direct-sow herbs. If you prefer to get your garden green quickly, gardening shops have plenty of young plants available for sale. Before shopping for annuals, you may want to consult the UT Gardens Annual Herbaceous Plant Trial Program data to see which cultivars of your favorite plant performed the best. Results for the garden in Knoxville and Jackson can be found at utgardens.tennessee.edu/annual_trials.html.
• Azaleas often show symptoms of lace bug and spider mite infestations during the hot months of summer. This damage can be prevented by a one-time, early application of the systemic insecticide imidacloprid. This insecticide should be poured in liquid form around the root system as the flowers fade, spreading the active ingredients throughout the plant tissue where it remains effective through the growing season. Bayer Advanced Tree and Shrub Insect Control is a common brand that contains this safe and effective insecticide. Always follow label directions when applying any pesticide.
For additional tips, visit the UT Extension website: extension.tennessee.edu and click on the menu link to “Publications.” Enter the term “landscaping” or “gardening” in the search engine.
The University of Tennessee Gardens include plant collections located in Knoxville, Crossville and Jackson. Designated as the official botanical garden for the State of Tennessee, the collections are part of the UT Institute of Agriculture. The Gardens’ mission is to foster appreciation, education and stewardship of plants through garden displays, educational programs and research trials. The Gardens are open during all seasons and free to the public. For more information, see the website: utgardens.tennessee.edu