Frequently Asked Questions
Blackspot is a common fungal disease of roses. Symptoms of blackspot are circular black spots on the leaves. Infected leaves turn yellow and drop prematurely. Initially, symptoms develop on the lower leaves and gradually move...
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....
Carefully examine the tree for the type and extent of damage. Trees that have split trunks or suffered extensive trunk damage are no longer structurally sound and should be removed. Large trees that have lost 50 percent or more of...
Plants in hanging baskets need to be watered frequently (especially in summer). Potting mixes are light, well-drained, and dry out quickly. Plus, hanging baskets may contain several plants. In general, water plants in hanging...
Muskmelon and watermelon are warm-season crops. Plant melons after the danger of frost is past and soil temperatures have warmed to 60 to 70 degrees Fahrenheit. Melons can be planted in mid-May in central Iowa. Gardeners in...
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...
The rutabaga performs best when planted in summer for a fall crop. Sow seed at a depth of 1/4 to ½ inch from June 15 to July 15 in Iowa. Rows should be spaced 18 to 24 inches apart. Thin the planting within a few weeks of...
The main objective in spraying apple trees is to prevent insect damage to the fruit. The most important period to spray apple trees is from petal drop until just prior to harvest. Several applications will need to be made during this...
The small, blue-flowering plant is probably Siberian squill (Scilla sibirica). Siberian squill is an early spring flowering bulb. Plants typically bloom in early to mid-April in Iowa. Bright blue flowers are produced on...
The large, green caterpillars are probably tomato hornworms. Tomato hornworms are bright green, up to 4 to 5 inches long, and have red or black, horn-like projections on their rear ends. After feeding, hornworms move to the soil where...
Early in the 1900's, white pine blister rust (Cronartium ribicola) became a serious disease problem in the United States. White pine blister rust requires both a currant or gooseberry (Ribes species) and white pine to...
Summer-flowering shrubs, such as potentilla and Japanese spirea, bloom in summer on the current year’s growth. Prune summer-flowering shrubs in late winter or early spring (March or early April in Iowa).
Do not mow shady areas less than 3 inches in height. Because of the lower photosynthetic rates in shady areas, the turfgrass plants need a large leaf surface to manufacture adequate amounts of food. The recommended mowing height for...
Red and purple raspberries are hardy throughout the state. Black raspberries, however, often suffer severe winter damage in northern Iowa and can be reliably grown only in central and southern portions of the state. ‘Black Hawk’ (an...
Fire blight is probably responsible for the wilted shoots on your crabapple. Fire blight is caused by the bacterium Erwinia amylovora. Plants susceptible to fire blight include apple, crabapple, pear, hawthorn, and...
Japanese beetles eat the foliage, fruits, and flowers of over 300 plants. When feeding on foliage, the beetles consume the tissue between the veins, leaving a lace-like skeleton. Flowers and fruits are sometimes devoured completely....
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...
Shedding bark on some trees is a completely normal development. The bark of most young trees is smooth and thin. As the tree grows, the bark layer thickens with the outermost tissue eventually dying. Continued growth pushes the bark outward,...
The frequency of watering may vary considerably from container to container. Watering frequency depends on the size and type of container, composition of the potting mix, plant species, and weather conditions. Some plants, such as...
Muskmelon Varieties
- ‘Earlisweet’ (early maturing, 2 to 3 lb. fruit)
- ‘Eclipse’ (round 6 to 8 lb. fruit)
- ‘Athena’ (oval 4 to 6 lb. fruit)
- ‘Aphrodite’ (oval 6 to 9 lb. fruit)
- ‘Superstar’ (oval 6 to...
When selecting plants for the shade garden, one group of plants that is often overlooked are native woodland wildflowers. Since they are native to the state, woodland wildflowers are well adapted to the area. They are easy to grow and...
The squash vine borer is a common pest of squash and pumpkins in home gardens in Iowa. Damage first appears as wilting of the vines. Eventually affected plants may collapse and die.
The adult squash vine borer is a wasp-...
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 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...
Determinate and indeterminate refer to the tomato’s growth habit. Determinate tomatoes are small, compact plants. They grow to a certain height, stop, then flower and set all their fruit within a short period of time. The...
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