KJFM NEWS — Garden Talk is produced monthly at the Adair County University of Missouri Extension Center in Kirksville, Mo.
Early to mid-May is the best time to plant warm-season annual flowers. These flowers grow best when the soil has warmed, days are sunny, and the air temperature is above 70 degrees. There are many flowers to choose from in several colors, shapes and forms. Rose moss, lantana and zinnias have good heat and drought tolerance. They grow well in the summer heat and thrive on little care. They also attract butterflies to the garden. Begonias, impatiens, coleus and torenia are shade tolerant annuals. They do well in morning sun and afternoon shade. All annuals may require deadheading (removal of spent flowers), fertilizing with a water-soluble fertilizer and regular watering, but their showy blooms provide beautiful color and gratification to gardens and landscapes.
Perennial flowers can be planted during May. Native plants tend to grow well in a wide range of soils, and often attract many types of pollinators like flies, bees, butterflies and even birds. Consider helping restore the monarch butterfly population and plant milkweed. Monarch populations have been in decline for several years due to loss of habitat and the use of pesticides. By planting their larval host food, milkweed, gardeners can help restore monarch numbers in their area. The Grow Native! website at https://grownative.org/ lists many perennial natives for sun, shade, dry and moist areas. Garden design plans can also be found on the website. Consider a mix of sedges, grasses and flowering plants in a native plant garden.
Spring blooming shrubs such as the forsythia and lilac should be pruned after bloom. It’s best to prune a third of the shrub at one time removing the old or dead branches. Then remove another third the following year and the remaining third the year after that. Pruning will encourage plant vigor by removing weak, overcrowded growth. Thinning a shrub in this way often improves the visual balance or symmetry of the plant. It can also allow for better air circulation which is important for lilacs which are susceptible to powdery mildew. Trees and shrubs that flower during the summer or early fall, should be pruned in winter or early spring before new growth begins. These plants develop flower buds during the spring of the flowering season. Examples would be Rose-of-Sharon and Butterfly Bush.
FRUITS AND VEGETABLES
Cool-season crops like radishes, peas, cilantro, spinach, lettuce and kale should still be producing well into late May. By June, they tend to bolt (set flowers), then die with the warmer days of summer. Remove what’s left of the plants, compost them, and plant another crop like green beans. After the beans are harvested and plants are spent, plant a cool-season crop again for fall. This is called succession planting, and it allows a gardener to grow a wider variety of vegetables in a small space. It’s a great way to maximize production of a garden. Succession planting can also be used to extend the harvest by staggering planting times for a single crop. For example, a gardener can make a planting of sweet corn and then make another planting two weeks later and one two weeks after that.
Plant flowers such as marigolds and nasturtiums among vegetables not only for color but for natural insect control. These flowers are companion plants to some vegetable crops and help repel insect pests in the garden.
Perennial crops like asparagus and rhubarb are ready for harvest April-May. Harvest asparagus spears when they are 6-8 inches long. When the majority of spears are the diameter of a pencil or less, allow them to develop into ferns. A pre-emergent herbicide like PREEN can be used after harvest for control of grassy weeds like foxtail and crabgrass. Rhubarb is ready to harvest when the stalks are about 8 inches long. Remove the leaf and discard. Do not harvest rhubarb the first year after planting. Holes bored into rhubarb stalks could be the work of the rhubarb curculio. It is a snout beetle that bores into the stalks, crowns and roots of rhubarb plants. Apply a recommended insecticide to the base of the plant. Rhubarb leaves get leaf spots, and at the end of the season, sanitation is really important to control them. Remove dead leaves from the plant and discard.
Strawberries are ready for harvest by late May in northern Missouri. Be prepared to protect strawberry plants in early May if danger of frost is present as cold temperatures can damage flowers. A row cover made of lightweight material can be applied. They can also be covered with straw, then remove it when the weather warms. Holes and bite marks in strawberries is usually from voles, mice or birds. This is often difficult to prevent. Gray mold or botrytis is a common fruit rot disease of strawberries. Symptoms are brown, rotting fruit with gray, fuzzy mold. Frequent rain, high humidity and moderate temperatures are prime conditions for botrytis.
DISEASES AND INSECTS
Warm, rainy and humid conditions during mid to late May in northern Missouri, typically brings the onset of disease on fruit trees and ornamentals. Fireblight, Anthracnose, Cedar-apple rust and Peach Leaf Curl are common fungal diseases this time of the year. Learn the symptoms and control methods for each of these diseases. Fungicides can be purchased at most garden centers or farm supply stores that can be used to help control the spread of the disease. Some insects to be on the look at for at this time are bagworms, aphids and tent caterpillars. Bagworms can be picked off from small trees and shrubs. The bags of tent caterpillars that form in the crotch angles of trees can be torn open for predators to consume. Aphids can be sprayed off of plants with a strong stream of water or use an insecticidal soap.
