Frequently Asked Questions

Question:
Why are some of the fruit on my summer squash misshapen?
Answer:

Misshapen fruit may develop if pollination is inadequate.   When pollination is incomplete, the fruit develops unevenly because the ovary wall enlarges more adjacent to fertilized seeds.  Inadequate pollination may be due to low...

Question:
What kind of yield can I expect from blueberries?
Answer:

Blueberry plants should come into full production by the fifth or sixth year.  Gardeners can expect to harvest 5 to 10 pounds of fruit per plant from mature highbush blueberries.  Half-high blueberries generally produce 1 to 3 pounds...

Question:
There are small, white objects resembling kernels of popcorn on the branches of my silver maple tree. What are they?
Answer:

The small, white, popcorn-like objects are likely cottony maple scale.  Cottony maple scale is an insect.  It is most commonly found on silver maple trees.  However, it can also be found on other maples, oak, linden, hackberry,...

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

The frequency of watering is determined by soil characteristics, weather conditions, type of plant material, and other factors.  In general, however, a deep watering once a week in dry weather should be adequate for most fruit, vegetable,...

Question:
When is the best time to water the garden?
Answer:

Early morning (5:00 to 9:00 am) is the best time to water the garden when using a sprinkler, garden hose, or any other device that wets the plant foliage.  When watering is completed, the plant foliage dries quickly.  The rapid drying...

Question:
Are there ways to reduce water use in the garden?
Answer:

Apply a mulch around landscape plantings and garden areas to conserve soil moisture.  Mulching reduces the rate of evaporation from the soil surface and also limits weed competition.  Organic materials, such as grass clippings, clean...

Question:
What is responsible for the yellow spots on my crabapple leaves?
Answer:

Cedar-apple rust is likely responsible for the yellow spots on the crabapple leaves.  Cedar-apple rust is a fungal disease.  The fungus  requires both a crabapple or apple and a cedar (juniper) to complete its life cycle. Crabapple...

Question:
The leaves on my sycamore have a bleached appearance in late summer. Why?
Answer:

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...

Question:
A small greenish worm is eating the foliage on my cherry tree. What should I do?
Answer:

The greenish worm is probably the pear slug.  The pear slug is not an actual slug.  It’s the larval stage of an insect (sawfly).  The pear slug feeds on pear, cherry, plum, and several other woody plants.  

The slug-...

Question:
Is it possible to control downy mildew on impatiens?
Answer:

In landscape plantings, control of downy mildew on impatiens with fungicides is not practical. Sanitation is the best management strategy for this disease. Remove and destroy infected plants as soon as they are noticed to reduce the spread to...

Question:
When should I harvest Brussels sprouts?
Answer:

Beginning at the base of the plant, harvest the buds (sprouts) when 1 to 1½ inches in diameter. Continue to harvest the sprouts higher up on the plant as they mature. Sprouts can be stored in a perforated plastic bag in the refrigerator...

Question:
I planted several peonies in late summer When will they begin to bloom?
Answer:

Many peony plants produce few, if any, flowers the first spring.  In fact, it’s advisable to pinch off any flower buds that develop the first spring to promote root and foliar growth.  Flower bud development requires a great deal of the...

Question:
The fruit on my zucchini squash began to grow, but quickly turned brown and rotted. Why?
Answer:

The rotting of the small squash fruits could be due to poor pollination or blossom-end rot. 

For squash fruit to develop fully, bees and other pollinators must transport pollen from the male flowers to the female flowers.  If the...

Question:
When should I cut gladiolus flowers for indoor use?
Answer:

Gladiolus for decorative indoor use should be cut as soon as the bottom flower on the spike has opened.  Most of the remaining blooms will open when the spike is brought indoors and placed in water.  When cutting gladiolus flowers,...

Question:
Is it possible to grow peanuts in Iowa?
Answer:

While peanuts are grown commericially in the southeastern United States, they can be grown in Iowa.  Their unique growth habit makes them a fun addition to the home garden. 

Growing Conditions

Peanuts grow best in loose...

Question:
I need to have some tree work done. How do I select a qualified arborist?
Answer:

Trees are valuable assets to the home landscape.  Occasionally the services of a professional arborist are needed to prune a large tree or assess the condition of a tree after a storm.  For many individuals, selecting an arborist is a...

Question:
When is the best time to water a lawn?
Answer:

Early morning (5:00 to 9:00 am) is the best time to water a lawn.  A morning application allows the water to soak deeply into the soil with little water lost to evaporation.  When watering is completed, the turfgrass foliage dries...

Question:
How do I control weeds in my asparagus planting?
Answer:

Weeds compete with asparagus for light, water, and nutrients and will reduce asparagus yield and quality if not controlled. Cultivation and hand pulling are the best ways to control weeds in an asparagus planting.  Hoe or...

Question:
My bittersweet vine doesn't produce any fruit. Why?
Answer:

American bittersweet (Celastrus scandens) is dioecious.  Dioecious plants bear male and female flowers on separate plants.  Gardeners need to plant at least one male and one female bittersweet vine to produce fruit. ...

Question:
How do I control nimblewill in my lawn?
Answer:

Nimblewill (Muhlenbergia schreberi) is a warm-season perennial grass.  Nimblewill is a thin, wiry grass that is pale green or gray-green.  It spreads by aboveground shoots or stolons, often forming circular spots in the lawn....

Question:
We recently moved into a home that has a large red raspberry planting in the backyard. How should we rejuvenate the planting?
Answer:

Red raspberries sucker freely.  If not confined, plants will spread rapidly.  Red raspberries are most productive when grown in 2-foot-wide hedgerows.  If the raspberry planting is several feet wide, plant rows need to be...

Question:
Are marigolds pest free?
Answer:

While marigolds are seldom bothered by insects and diseases, they are not problem free.  Spider mites can devastate marigolds in hot, dry weather.  Grasshoppers can also cause considerable damage.  Aster yellows is an occasional...

Question:
When should I plant Chinese cabbage?
Answer:

Chinese cabbage performs best when planted in summer for a fall crop.  (Chinese cabbage frequently goes to seed when planted in spring.)  Sow the seed of Chinese cabbage at a depth of 1/4 to ½ inch in July.  Rows should be spaced 2...

Question:
When can I cut back peony foliage?
Answer:

Cut back peony foliage after it has been destroyed by a hard freeze.  In Iowa, late October or early November is generally a good time to cut back peonies.  Cut off the stems near ground level.  If the peonies experienced foliar...

Question:
Are there special corn varieties that are grown to produce "baby" corn?
Answer:

The small size of “baby” corn suggests that it’s a special variety.  However, most baby corn is actually grown from regular sweet and field corn varieties.  The ears are harvested when they are 2 to 4 inches long and 1/3 to ½ inch in...

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