Frequently Asked Questions

Question:
How can I control Colorado potato beetles?
Answer:

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...

Question:
What are some good, long-lived perennials?
Answer:

When selecting perennials for the home landscape, it’s important to consider their size, bloom period, hardiness, and cultural requirements.  Another consideration is their longevity.  Some perennials are short-lived.  Short-lived...

Question:
How can I prevent blight on my tomatoes?
Answer:

Foliar diseases of tomatoes are a common problem in the home garden.  Fungal diseases, such as early blight and Septoria leaf spot, overwinter on plant debris in the soil.  Fungal spores are splashed onto plant foliage by raindrops or...

Question:
Can dog or cat feces be placed in the compost pile?
Answer:

It is advisable not to add dog or cat feces to the compost pile.  Dog and cat feces may contain harmful pathogens that may not be destroyed during the composting process. 

Question:
When should I plant garlic?
Answer:

Garlic cloves should be planted in fall (October to early November) or early spring (late March to mid-April).  Plant cloves 1 inch deep with the pointed side up.  Fall-planted garlic should be mulched with a 4- to 6-inch-layer of weed-...

Question:
The flesh near the centers of my apples has a glassy appearance. Why?
Answer:

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...

Question:
How can I prevent deer from rubbing off the bark on small trees in the yard?
Answer:

In fall, bucks rub their antlers on trees to remove the dried velvet from their antlers and to mark their territory.  This rubbing removes the thin layer of bark on small trees and can seriously damage or destroy them.  Trunk damage...

Question:
What is the correct mowing height for a lawn in summer?
Answer:

Kentucky bluegrass and other cool-season grasses thrive in the cool weather of spring and fall.  Hot, dry conditions in summer are stressful for cool-season grasses.  Kentucky bluegrass lawns should be mowed at a height of 3 to 3½...

Question:
How can I keep birds from eating my grapes?
Answer:

The best way to prevent birds from eating the grape crop is to place netting over the grapevines.  Netting can be purchased at garden centers or through mail-order companies.  When placing netting over the grapevines, make sure the...

Question:
How can I prevent "bees" from damaging my grape crop?
Answer:

The bee-like insects are probably yellowjackets.  Yellowjackets are social wasps that build paper nests either in the ground, a log or landscape timber, or building wall or attic.  The workers from the colony travel up to a few hundred...

Question:
There are several bands of holes around the trunk of my pine tree. Is the tree infested with borers?
Answer:

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...

Question:
How often should I water my roses?
Answer:

Modern roses, such as hybrid teas, floribundas, and grandifloras, require watering during hot, dry weather.  The frequency depends upon weather conditions and soil type.  In most gardens, a thorough watering every 7 to 10 days during...

Question:
Should I fertilize my June-bearing strawberries in spring?
Answer:

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...

Question:
The leaves on several of my hostas have turned yellow, then brown, and finally collapsed onto the ground. What is happening to my hostas?
Answer:

The hostas may have petiole rot.  Petiole rot is a serious disease of hosta.  It is caused by the fungus Sclerotium rolfsii var. delphinii.  (Petiole rot can also affect daylily, peony, phlox, columbine, and other...

Question:
How should I store potatoes?
Answer:

After harvesting the potatoes, cure the tubers at a temperature of 50 to 60 degrees Fahrenheit and high relative humidity (85 to 90 percent) for two weeks.  The curing period allows minor cuts and bruises to heal.  Thickening of the...

Question:
What are some good low-growing groundcovers?
Answer:

Plant heights vary somewhat based on the growing conditions at the site.  However, there are several groundcovers that are 12 inches or less in height. 

Shade Groundcovers

Low-growing groundcovers for shade include:...

Question:
Even though I water my garden, one of my tomato plants is wilting. What could be wrong?
Answer:

A vascular wilt may be responsible for the wilting of the tomato plant.  The initial symptoms of Verticillium and Fusarium wilts are wilting of the plant leaves during the heat of the day.  Affected plants often recover in the evening...

Question:
Should I apply lime to my garden?
Answer:

 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...

Question:
When should I harvest garlic?
Answer:

Harvest garlic when the foliage begins to dry.  In Iowa, garlic is usually harvested in August or September.  Carefully dig the bulbs with a garden fork or shovel.  Dry the garlic in a warm, dry, well-ventilated location. ...

Question:
There are black spots on the surface of my apples. Can I eat the skins?
Answer:

The black spots are probably sooty blotch or flyspeck.  Sooty blotch and flyspeck are two different fungal diseases that often occur together on apples.  Sooty blotch appears as dark brown to black, ½ inch or larger smudges on the...

Question:
The leaves on my red-twigged dogwoods are spotted and beginning to fall off. Why?
Answer:

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...

Question:
What is the proper mowing height for shady turfgrass areas?
Answer:

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...

Question:
What type of pruning equipment is needed to prune grapevines?
Answer:

Tools required to prune grapevines include a hand shears, lopping shears, and saw.  Brightly colored ribbons or cloth strips can be used to identify fruiting canes and renewal spurs.  

Question:
What are some good forsythia varieties for Iowa?
Answer:

When selecting a forsythia, choose a cultivar that reliably blooms in Iowa.

Forsythias to avoid planting in Iowa

The flower buds on some varieties are not reliably cold hardy in Iowa, and typically don’t bloom well in Iowa as...

Question:
How can I control blackspot on my roses?
Answer:

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...

Pages