1. Evergreen vining plants such as greenbriar, English ivy and Japanese honeysuckle are best controlled using a spray herbicide once the first three to five leaves have developed. Systemic herbicides containing glyphosate, triclopyr or dicamba are generally available at garden centers for this purpose. It is especially important to know that residual chemicals in the soil can damage emerging plants in woodland gardens, so read labels thoroughly before applying herbicides to avoid soil contamination. Gardeners can use a foam paintbrush or sponge to treat individual weeds. Always wear chemical-resistant gloves and goggles when handling pesticides.
2. Planting is also high on the list of landscaping chores during May. Flowering annuals/bedding plants are best planted before drier conditions arrive, especially in the warmer Zone 8 region of the state. Bedding plants benefit from generous amounts of soil conditioner or compost turned into the soil at planting. In the absence of a soil test, use a phosphorus-rich fertilizer to encourage flowering and root development. Gardeners can use weekly applications of soluble fertilizer to push the plants to maturity.
3. With a few tips on selecting bedding plants, a trip to the garden center is less intimidating. Flowering and vegetable transplants are sold in cell packs of four, six, or eight. If you have the choice, select deeper cells to more shallow ones. Shop for quality transplants that are stocky and well maintained. Yellowing leaves on the lower foliage may indicate insufficient watering or nitrogen deficiency. Check the undersides of leaves for insects, especially whiteflies. If you have the space, buy transplants by the flat for the best price — there are usually 24 or 72 plants in flats. Before you plant, water the flats thoroughly to make it easier to remove the transplants. Loosen the roots of pot-bound transplants and avoid planting too deeply. Mulch and water well.
4. Pay attention to irrigating all new plantings. Bedding plants are high water users, while shrubs and trees benefit from irrigation throughout the first growing season. Most plants need the equivalent of an inch of rainfall each week during the hot months of summer. Trees can be watered with a tree watering bag, or a drip irrigation line. One rule of thumb is to supply a gallon of water per inch of trunk diameter as a weekly irrigation. Sandy soil types may require more water. Fertilization is not a major issue during establishment of woody landscape plants, and can cause more harm than good when overdone with commercial farm fertilizer products. Specialty fertilizers, which contain organic nutrients, compost or slow-release fertilizers are best for woody plant maintenance following the establishment period.
5. Fertilize cutting roses monthly with either a specialty fertilizer, a 10-10-10 mixture, or on an as-needed basis to keep them vigorous. Fungicide applications are essential to keep tea roses free of blackspot and canker diseases. Soap or horticultural oil spray applications help to eradicate damaging aphid populations, but cease spraying when daytime highs exceed 86 degrees Fahrenheit.
6. Groom flowering shrubs that have finished blooming. Prune away old flowering branches and groom plants for the season ahead. Kerria and forsythia are always in need of remedial spring pruning.
7. Perennial plants such as mums, asters, goldenrod and phlox, will benefit from “pinching.” You do this by removing approximately two inches of the growing tips to force side shoots. Pinched plants will become bushy and produce more blooms. Repeat this at least twice to keep their height down.
8. Remember to call 811 before you dig those deep planting holes. Severing underground utility lines can be avoided with this public service. Public rights-of-way are especially vulnerable to disrupting power to your community and stiff fines can be imposed for this violation.
9. Leaf compost is available this time of year. Stock up and use for preparing new flower gardens. Leaf compost and shredded hardwood makes great mulch under shade trees.
Fruit and Vegetable Gardens
10. Fruit trees need attention for pest management concerns. Stone fruits, such as peaches, nectarines, plums, or apple trees are susceptible to fruit damaging diseases. Applications of fungicides must be timed purposefully to prevent fruit rots later in the season. Fruit thinning is in order on all fruit trees to relieve disease pressure and ensure larger fruit. Additional fertilization is recommended once fruit begins enlarging. Calcium nitrate is a good fertilizer for fruit plants.
11. Berries and grapes are a delight to have in the home garden. Construct a sturdy trellis for vines and stake berries with metal fence stakes. Electrical wire ties and twist ties are best for attaching vines to support wires. Deer and Japanese beetles are common pests that relish grape foliage, so monitor your gardens closely. Maintain a weed-free zone around the base of plantings.
12. Warm-season vegetables can be safely planted without fear of frost injury. Warm soil is what these crops need to establish quickly. They include peppers, beans, squash, pumpkins, melons, tomatoes, okra and sweet potatoes.
13. Rotating crops in a garden is an accepted pest management practice in horticulture. One approach is to move crops around based upon their botanical families. In large gardens, cover crops can be used in the rotation to build organic matter and capture nitrogen.
14. Continue harvesting cool-season vegetables; such as sugar snap peas, leafy greens, lettuce, and asparagus. Check your garden routinely and make timely harvests for the highest quality vegetables.
15. Strawberry harvest season requires daily attention to picking ripe berries and disposing of moldy fruit. Continue irrigating in the early morning hours. Remove weeds to reduce disease and insect populations.
16. Monitor your garden for early insect appearance. Worms in crucifers (cabbage, greens, and broccoli) are especially troublesome. Check the undersides of leaves for worms; handpick and destroy them, or in large plantings, choose the biological products containing BT to rid them. Tent caterpillar nests should be destroyed. Do not remove praying mantis egg cases. These beneficial insects are beginning to emerge from their overwintering cases. Soft insecticides (insecticidal soap, horticultural oil, botanical sprays) are best for spring pests.
17. Successive plantings of vegetables will ensure a longer harvest seasons. The most common varieties to sow are snap beans, southern peas, root crops, cucumbers and squash.
18. Tomatoes are an important vegetable for most city gardeners. Select a large container that is at least five gallons in size. If you choose a bucket, don’t forget to drill drainage holes on the lower sides. A commercial potting soil that has moisture polymers for water retention will be helpful as summer approaches. Tomatoes flourish in full sun; they need plenty of fertilizer and water. There are some specialty tomato fertilizers at garden shops that may be beneficial for container growing. It is best to hold back on fertilizing until the first tomatoes form; too much nitrogen and you will have big green plants and no tomatoes!
19. When preparing garden soil for planting, in the absence of a soil test, apply limestone at the rate of five pounds per 100 square feet and superphosphate (0-18-0) at a four-pound rate. The addition of compost or another organic source will help loosen the soil and conserve moisture in drier summer conditions.
20. Mowing lawns is at the top of the list of gardening chores this time of year regardless of the turfgrass variety. Warm-season turfgrass varieties, such as Bermuda grass, St. Augustine and zoysia, are fertilized monthly until late summer, or as needed based on a soil test. These lawns can produce a lot of thatch and benefit from an annual dethatching as the thatch layer approaches one-half inch. Core aerification is another practice used to reduce soil compaction for enhanced root growth. Verticutting is a standard practice with dense St. Augustine grass lawns. Beware that centipede grass can be injured with fertilization. Tall fescue lawns require no further fertilizing if they are managed by irrigation and a professional lawn service. For more information on lawn management, request or download a copy of the “Lawn Maintenance Calendar” from N.C. Cooperative Extension for your turfgrass type.
21. Two seasons of broadleaf weeds can be found in lawns and other garden spaces during May. This transitional period has both winter annual weeds that are waning and summer annual weeds that are rapidly growing. Crabgrass is the common concern, since its seeds germinate from spring to frost. Lawns infested with crabgrass are frequently treated with split applications of pre-emergence herbicide. Lawn herbicides are formulated with fertilizer (weed-N-feed) or without. Granular/dry formulations must be applied in a spreader calibrated to ensure even distribution. It may help to purchase a preventer chemical sold with the manufacturer’s application equipment to reduce the chance of error. Always follow label directions for rates and timing instructions. Removing individual clumps of perennial weeds by hand and spot spraying small weed infestations is an ecologically sound management approach.