Frequently Asked Questions
Newly emerged tree and shrub foliage is susceptible to damage from below freezing temperatures. The new growth on many trees and shrubs can tolerate temperatures in the low 30s and upper 20s. Freeze damage is most likely when temperatures drop...
Newly emerged perennial growth is susceptible to damage from freezing temperatures. While freezing temperatures may have damaged or destroyed the new growth, the roots and crowns of healthy, well-established perennials should still be alive...
Most lawns in Iowa require 1 to 1½ inches of water per week. When watering the lawn, apply this amount in a single application or possibly 2 applications 3 or 4 days apart. Avoid frequent, light applications of water which promote...
If the strawberry patch is being overrun with perennial grasses, such as quackgrass, control is not very practical. Your best option would be to prepare a new site for a strawberry bed this summer or fall and plant a new bed next spring....
The magic lily (Lycoris squamigera) is a rather intriguing plant. Other common names include resurrection lily, surprise lily, hardy amaryllis, and naked lady. The life cycle of Lycoris squamigera is different from...
Before applying any herbicide, carefully read and follow label directions. When applying liquid formulations, potential spray drift problems can be avoided by following simple precautions. Don’t spray when winds exceed 5 mph....
Cabbageworms are greenish caterpillars that eat large, irregular holes in the foliage of cabbage, broccoli, cauliflower, and Brussel sprouts. Cabbageworms can be controlled with biological or chemical insecticides. Bacillus...
Wood ashes contain small amounts of several plant nutrients. The nutrient content of wood ashes depends on the type of wood burned, the thoroughness of its burning, and other factors. Generally, wood ashes contain 5 to 7 percent potash, 1 percent...
Martha Washington or regal geraniums (Pelargonium x domesticum) produce beautiful flowers. Unfortunately, cool (50 to 60°F), night temperatures are required for flower formation. Few flowers form during the summer...
The Colorado potato beetle is difficult to control. Hand picking is a control option for individuals with small gardens. Hand-pick beetles, eggs, and small larvae from infested plants as soon as possible (practical for a few insects...
Forsythias bloom on the previous year’s growth. The best time to prune forsythias is immediately after flowering. Pruning forsythias anytime from mid-summer until just prior to bloom will reduce flowering in spring. When pruning...
The symptoms on your bee balms (Monarda spp.) are most likely due to powdery mildew. Powdery mildew is a common fungal disease on bee balms. Symptoms are most severe on overcrowded plants and those growing in partial shade....
Summer and winter squash are warm-season crops. Plant squash after the danger of frost is past. In central Iowa, summer and winter squash can be planted in mid-May. Gardeners in southern Iowa can plant 1 week earlier. ...
Cherries are short-lived trees in Iowa, especially in poor sites. Sweet cherries seldom live beyond 10 to 15 years. Sour or tart cherries may survive for 20 to 25 years. When selecting a planting site, be sure to choose a well-...
Ash rust is probably responsible for the orange growths on your ash tree. Ash rust is caused by the fungus Puccinia sparganioides. The fungus produces conspicuous swellings on leaves, petioles, and twigs. Infected...
There are several possible explanations why peony buds fail to open.
Not Receiving Enough Sunlight
Peonies bloom best in full sun. In partial to heavy shade, plants are weak and may not be able to supply adequate food...
There are different ways to classify or categorize plants and plant structures. We eat many plant parts including roots, stems, leaves, flowers, seeds, and fruit. The root is the edible portion of carrots, radishes, beets, and...
Brown rot is a common fungal disease of peaches and other stone fruits. Affected fruits develop circular light brown spots that expand rapidly and rot the fruit. Sometimes the fungus that causes this rot is visible as ash-gray tufts....
The holes were likely created by sapsuckers. Sapsuckers, members of the woodpecker family, damage trees by drilling holes in the trunk or large branches. Sapsucker damage is very distinctive. They drill uniform, 1/4 inch holes...
The growth in your perennial bed is probably a slime mold. Slime molds are types of fungi. Slime molds feed on bacteria and other organisms in the mulch. They do not harm plants.
Slime molds are usually a temporary nuisance. Within a few...
Thatch is the layer of dead and living plant material that forms between the soil surface and green vegetation. It is composed of shoots, crowns, and roots. Thatch, to some degree, is present in all lawns. However, when thatch...
The gray, velvety growth on your berries may be gray mold. It is also known as Botrytis fruit rot. Gray mold is favored by poor air circulation and a high humidity in the strawberry planting. The most commonly infected berries...
Many lily enthusiasts don’t grow tiger lilies (Lilium tigrinum) because they are often infected with lily mosaic virus. Lily mosaic virus causes little harm to tiger lilies. Oftentimes, you can’t tell that they have the...
Greenbug aphids may be responsible for the brownish orange color of the turfgrass. Greenbug aphids feed only on plants of the grass family (Kentucky bluegrass, corn, sorghum, etc.). Greenbugs live on the grass blades and feed on sap...
Cucumbers and other vine crops are monoecious. Monoecious plants have separate male and female flowers on the same plant. Male and female flowers are similar in appearance. However, the female flowers have small, immature fruits...
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