Deadheading is the removal of spent or faded flowers. There are several benefits to deadheading garden phlox. Deadheading improves the appearance of plants, may encourage a second flush of bloom, and prevents self-seeding. …
In Iowa, gardeners should apply lime to gardens and lawns only when recommended by a soil test. A soil test will indicate the current soil pH and, if necessary, the amount of lime to apply to the area. Liming materials include ground…
Established plantings of June-bearing strawberries should not be fertilized in spring. Spring fertilization stimulates foliar growth, produces softer berries, and increases disease problems. Lush, vegetative growth may make picking…
Ideally, you would apply fertilizer to the lawn just before a light rain. Alternatively, you can water the lawn just after the application. This allows the fertilizer to be readily absorbed into the soil, where the plants can use it.…
When the lawn is mowed properly, grass clippings do not need to be removed or bagged. Small clippings filter down into the turf and quickly decompose, returning essential plant nutrients to the soil. Lawn clippings do not…
Insecticide treatments are available to protect ash trees from the emerald ash borer. However, treatments should be undertaken only when necessary to prevent excessive and needless use of insecticides.
Watering raspberry plants during dry weather can help insure a good crop. Adequate soil moisture levels are necessary throughout the growing season for good raspberry production. However, the most critical time for moisture is from…
Several factors could be responsible for the uneven ripening of the berries within a cluster. Possible causes are over-cropping (too many grape clusters on the vine), a potassium deficiency, moisture stress, or 2,4-D damage.
Black rot is probably responsible for the damage to the grapes. Black rot is caused by the fungus Guignardia bidwellii. This fungal disease is common in home and commercial vineyards in Iowa, especially in warm, humid summers…
The orange substance on your black raspberry leaves is orange rust. Orange rust occurs on black and purple raspberries and most varieties of blackberries. Orange rust does not occur on red raspberries.
Poorly filled ears are usually the result of poor pollination. Hot, dry winds and dry soil conditions may adversely affect pollination and fertilization and result in poorly filled ears. Water sweet corn during pollination if the soil is…
Water core is probably responsible for the glassy appearance to the apples. Water core is a physiological disorder that develops before harvest and is characterized by translucent, water-soaked areas in the flesh. These water-soaked…
The browning of the honey locust foliage is probably due to the mimosa webworm. Damage occurs when the caterpillars tie honey locust leaflets together and feed on the foliage inside the tightly compressed, protective webs. Affected…
The common bleeding heart (Dicentra spectabilis) typically dies back in mid-summer in Iowa. However, plants may die back in late spring or early summer if growing conditions are not favorable. The common bleeding heart…
The spotting and premature leaf drop on your dogwoods is probably due to Septoria leaf spot. Septoria leaf spot is a common fungal disease of dogwoods in Iowa. The disease typically causes irregularly shaped grayish spots with dark…
In Iowa, the foliage of the river birch (Betula nigra) often turns a sickly yellow-green. The yellow-green foliage is due to a deficiency of iron. The problem is referred to as iron chlorosis. (A close examination of chlorotic leaves…
The bleached appearance may be due to lace bugs. Lace bugs are sap feeding insects commonly found on the leaves of shade and ornamental trees in Iowa. The most commonly affected trees are hackberry, sycamore, and oak. Adult lace…
Broken or damaged tops are common on young trees due to wind, ice, wildlife, winter dieback or equipment injury. While this damage can affect tree form, most young trees recover well if corrective pruning is done early. The primary goal is to…
The thin areas can be repaired by overseeding. Overseeding is the sowing of grass seed into an existing lawn. In Iowa, late summer (mid-August to mid-September) is the best time to overseed a lawn.
The brown streaks in the apples are probably due to the apple maggot. The apple maggot is the most serious insect pest of apples in Iowa. Apple maggot damage appears as knobby, misshapen fruit with small pits or blemishes on the fruit…
The horizontal circular webs were created by various spiders collectively called grass spiders. They are harmless to the grass and ecologically beneficial as predators. The webs accumulate between rain showers and mowings. They…
The small, black beetles are likely sap beetles. They are also known as picnic beetles or picnic bugs. Sap beetles commonly feed on over-ripe or damaged fruits and vegetables in the garden.
The wart-like growths on the hackberry leaves are galls. Galls are abnormal growths of plant tissue induced to form by mites, insects, or other small organisms. They are quite common on trees.
The white, fuzzy objects on the branches of your maple tree are wooly alder aphids. (The insect is also known as the maple blight aphid.) Wooly alder aphids feed on the sap of maple trees from bud-break until late June. Then…
The white, raised spots on your potatoes are probably swollen lenticels due to wet soil conditions. Potato tubers are enlarged underground stems. Lenticels are small openings in the tuber surface that allow for gas exchange. …
The growth on the trunk of the maple tree is likely a burl. Burls are abnormal swellings or growths that develop on the trunks and branches of trees. Burls can be found on deciduous trees and evergreens. The exact cause is…
The large, hard growth is probably crown gall. Crown gall is caused by the bacterium Agrobacterium tumefaciens. The bacterial disease can infect roses, grapes, apples, raspberries, willows, euonymus, and many other woody…
The foul-smelling objects are likely stinkhorns. Stinkhorns are a type of fungus or mushroom. The common name is derived from their appearance and smell. Stinkhorns usually appear in cool, wet periods in late summer and early fall.
The “worms” are likely fall webworms. Fall webworms are hairy, tan to yellow caterpillars. As they feed, fall webworms construct tents or webs at the ends of branches. Tents are initially small, but the caterpillars enlarge the…
