April is the month for gardeners. All the world seems to be in bloom and gardening enthusiasts are just waiting for assurances that the last frost for the spring has passed. For much of the state April 15 is the “safe date” but estimates are available from the National Weather Service for specific locations.
Jason Reeves, curator of the University of Tennessee Gardens, Jackson, offers these tips for coordinating a few of your outdoor efforts as you struggle to install landscape plants and gardens:
· Tomatoes, peppers, eggplant, okra, basil, sweet potatoes pumpkin and gourds resent cool temperatures, so despite your enthusiasm, wait until night temps are consistently above 50 degrees F to plants. Wait also for the ornamentals vinca, lantana, ornamental sweet potatoes and caladiums.
· Prune spring-flowering shrubs (azaleas, flowering quince, Forsythia and Loropetalum) soon after they finish flowering, but only if they need it. Selectively cut old or unruly branches by reaching deeply into the shrub leaving no visible stub, making the cut just above a joint. This pruning method will keep them from looking like meatballs.
· A good option for Loropetalums that have outgrown their space is to tree-form them. They can easily be limbed up by removing lower branches. Loropetalum ‘Crimson Fire’ is a new dwarf from that has proven to be hardy 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.
· Kerria japonica, also known as Japanese kerria or yellow rose of Texas, often has dead branches. Follow them to the base to cut them. Remove older branches the same way to keep the plant looking good. Older, overgrown or neglected plants can be cut to the ground for rejuvenation.
· 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.
· You can 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.
· Try the annual moon vine, Ipomoea alba, this year to attract sphinx moths to your garden.
· Spring is a good time to freshen up the mulch in your landscape. Remember not to pile it around the trunks of your trees and shrubs. If using a pre-emergent herbicide, be sure to apply it before spreading your mulch to prevent the sunlight from breaking it down. It also forms a more effective barrier when allowed to bond with soil particles. Remember it is not necessary to fertilize well-established trees or shrubs. If you are trying to encourage faster growth on new plantings, a balanced granular fertilizer scattered on the soil surface is effective. Be careful not to overdo it. Tree spikes or drilling fertilizer into the root zone is unnecessary and expensive.
· Cut back any woody perennials that may need it, like rosemary, rue, lavender, Santolina and Artemisia. If done before the danger of frost has passed, new growth may appear, and a freeze can kill that new growth and sometimes the entire plant.
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. You can also contact your local county UT Extension agent.