Frequently Asked Questions

Question:
Why isn’t my apple tree bearing fruit?
Answer:

The lack of fruit is likely due to the absence of flowers, poor pollination, or low temperatures during bloom.  

The lack of flowers is often due to the age of the tree.  After planting, most dwarf and semi-dwarf apple trees don’...

Question:
How do I care for a jade plant?
Answer:

Place the jade plant (Crassula argentea) in a sunny window where it receives at least 4 hours of direct sunlight.  The jade plant is a succulent which stores water in its foliage and stems.  Overwatering (watering too...

Question:
How do I care for an umbrella tree?
Answer:

The umbrella tree (Schefflera actinophylla) is native to rainforests in Australia and New Guinea.  In the home, place the umbrella tree in bright, indirect light near an east, west, or south window.  Allow the potting soil to...

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:
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:
Which native ferns are suitable for the home landscape?
Answer:

Native ferns that are good additions to shady locations in the home landscape include the northern maidenhair fern (Adiantum pedatum), lady fern (Athyrium filix-femina), intermediate wood fern (Dryopteris intermedia),...

Question:
Which native shrubs can be grown in shady locations in the home landscape?
Answer:

Native deciduous shrubs that can be successfully grown in partial shade include serviceberry (Amelanchier arborea), pagoda dogwood (Cornus alternifolia),  gray dogwood (Cornus racemosa), bush honeysuckle (...

Question:
How do you renovate June-bearing strawberries?
Answer:

A June-bearing strawberry planting can be productive for 4 to 5 years if the bed is given good care.  One important task is to renovate June-bearing strawberries immediately after harvest.  The renovation process involves leaf removal,...

Question:
How long can I expect my June-bearing strawberry planting to be productive?
Answer:

June-bearing strawberry plantings that are well-maintained and renovated annually should remain productive for 4 or 5 years.  Poorly managed beds may be productive for only 1 or 2 years.  It’s time to plant a new strawberry bed when...

Question:
Is it necessary to water an established lawn during hot, dry weather?
Answer:

Gardeners have two basic options when confronted with hot, dry weather.  One option is to do nothing and allow the grass to go dormant.  The alternative is to water the turfgrass during dry weather to maintain a green, actively growing...

Question:
Should I fertilize the lawn in summer?
Answer:

Do not fertilize Kentucky bluegrass and other cool-season grasses during the summer months (June, July, and August).  The best times to fertilize cool-season grasses in Iowa are spring, mid-September, and late October/early November. ...

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:
When should I apply a preventive type insecticide to control white grubs in the lawn?
Answer:

White grub populations and damage to lawns vary greatly from year to year and place to place, even varying from spot to spot within the same lawn due to variations in beetle numbers, weather, turfgrass vigor, soil conditions, and other factors....

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...

Question:
There are round holes in the foliage of my roses. What is responsible for the damage?
Answer:

Leafcutting bees are probably responsible for the holes in the rose foliage.  Leafcutting bees resemble honey bees, but are often darker in color.  Female leafcutting bees make nests in rotted wood or the stems of plants.  The...

Question:
Small, green worms are eating the foliage on my roses. What should I do?
Answer:

The small, green “worms” are probably the larvae of the rose sawfly.  Rose sawfly larvae (commonly referred to as roseslugs) have tapered bodies, may be up to ½ inch in length, and are pale green in color.  The larvae somewhat resemble...

Question:
There are erect, hair-like growths on the upper leaf surface of my maple tree. Should I be concerned?
Answer:

The hair-like growths are likely galls.  Galls are abnormal growths of plant tissue induced to form by mites, insects, or other small organisms.  The hair-like gall on the maple leaves is probably the maple spindle gall. 

...

Question:
My crabapple has begun to drop some of its leaves. Why?
Answer:

The leaf drop is probably due to apple scab. Apple scab is a fungal disease caused by the fungus Venturia inaequalis. Cool, wet weather in spring favors apple scab development. Crabapple varieties differ in their susceptibility to apple...

Question:
Several new shoots on my crabapple have turned brown and wilted. What is the problem?
Answer:

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...

Question:
There are black spots on my maple leaves. Is this a serious problem?
Answer:

Tar spot is a common leaf spot on maples in the United States.  Several fungi in the genus Rhytisma cause tar spot.  Fortunately, tar spot does not cause serious harm to maple trees.  The damage is mainly cosmetic. ...

Question:
There are gray-green patches on the trunk of my tree. What are they? Are they harming the tree?
Answer:

The gray-green patches are probably lichens. Lichens are unusual organisms. They consist of two unrelated organisms, an alga and a fungus. These two components exist together and behave as a single organism. The agla provides food via...

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