Frequently Asked Questions

Question:
The bottom of my black raspberry leaves are covered with an orange substance. What is it?
Answer:

The orange substance on your black raspberry leaves is orange rust.  Orange rust occurs on black and purple raspberries and most varieties of blackberries.  Orange rust does not occur on red raspberries. 

Orange rust...

Question:
I would like to move a small tree in the yard. How should I proceed?
Answer:

Early spring (before leaves emerge) and fall (after leaf drop) are the best times to transplant deciduous trees.  Evergreens are most successfully transplanted in early spring and late summer (late August to mid-September). 

To...

Question:
There are areas in my lawn where the grass is rather sparse. How do I fix these areas?
Answer:

The thin areas can be repaired by overseeding.  Overseeding is the sowing of grass seed into an existing lawn.  In Iowa, late summer (mid-August to mid-September) is the best time to overseed a lawn. 

Good site preparation...

Question:
When should you harvest onions?
Answer:

Onions should be harvested when most of the tops have fallen over and begun to dry.  Carefully pull or dig the bulbs with the tops attached.  

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:
Can I keep rabbits out of my vegetable garden by planting marigolds around the perimeter?
Answer:

Marigolds do not repel rabbits, deer, or other animals.  In fact, rabbits occasionally browse heavily on marigolds.  Erecting a chicken wire or hardware cloth fence around the vegetable garden is the best way to keep rabbits out of the...

Question:
When should I harvest my summer squash?
Answer:

Harvest zucchini and other long-fruited summer squash varieties when the fruit are 1½ to 2 inches in diameter and 6 to 8 inches long.  Scalloped types are best when 3 to 5 inches in diameter.  Fruit should have soft skins (rinds) that...

Question:
How can I control squash bugs?
Answer:

Squash bugs can be serious pests of summer and winter squash.  Squash bugs have piercing-sucking mouthparts.  Heavy feeding causes entire leaves to wilt, turn brown, and die.  Several methods can be used to control squash bugs in...

Question:
A large evergreen was partially uprooted in a storm. Can I save it?
Answer:

Tree roots are not as deep as most people imagine.  Most tree roots are located in the top 12 to 18 inches of soil.  While tree roots are quite shallow, they often extend out into an area that is 2 to 3 times larger than the crown area...

Question:
My peonies bloom poorly. What could be wrong?
Answer:

There are several factors which may cause peonies to bloom poorly.  Peonies perform best in areas that receive at least 6 hours of direct sun each day.  Peonies that receive less than 4 hours of direct sun will not bloom well. ...

Question:
When should I harvest herbs?
Answer:

Most herbs are ready to be harvested when flower buds appear on the plants, but before the buds open.  The leaves contain the maximum amount of volatile oils at this stage of growth, giving the greatest flavor and fragrance to the finished...

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:
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:
How should I water a newly seeded lawn?
Answer:

After seeding, keep the upper 1 inch of soil moist by watering once or twice a day.  With adequate moisture and warm soil temperatures (55 degrees Fahrenheit or above), the seeds of most turfgrasses should germinate in 2 to 3 weeks....

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:
How do I control mealybugs on a houseplant?
Answer:

Mealybugs on houseplants are difficult to control.  Unless the plant is particularly valuable, it’s often best to throw away the infested plant before the insects spread to other houseplants.  The standard remedies for houseplant pests...

Question:
How do I control dandelions and other broadleaf weeds in my lawn?
Answer:

In small areas, some weeds can be controlled by pulling and digging.  This method is best accomplished after a soaking rain or deep watering.  Unfortunately, pulling and digging is often ineffective on deep-rooted weeds. 

In...

Question:
Can blackberries be successfully grown in Iowa?
Answer:

The growth and fruiting characteristics of blackberries are similar to raspberries.  The blackberry plant’s roots and crown are perennial, while its stems or canes are biennial.  Blackberry canes are strictly vegetative during the first...

Question:
When would be a good time to move an evergreen tree with a tree spade?
Answer:

Early spring (before bud break) is the best time to transplant evergreens.  Evergreens can also be transplanted in late summer (late August to mid-September).  Evergreens transplanted after mid-September may not have adequate time to...

Question:
I can't get grass to grow under a large maple tree. What are my options?
Answer:

Most turfgrasses have a difficult time growing in the vicinity of large shade trees.  If your efforts to grow turfgrass are unsuccessful, there are alternatives.  Areas around and beneath trees can be mulched with wood chips or shredded...

Question:
How do you harvest, dry, and store onions?
Answer:

Onions should be harvested when most of the tops have fallen over and begun to dry.  Carefully pull or dig the bulbs with the tops attached. 

Harvesting and Drying

After harvesting, dry or cure the onions in a warm, dry...

Question:
The leaves on my lilac are covered with a white substance. Is this a serious problem?
Answer:

The white substance is likely powdery mildew.  Powdery mildew is a fungal disease.  It appears as a white, dusty growth on plant foliage.  In the home landscape, powdery mildew is commonly found on lilac, phlox, monarda, zinnia,...

Question:
How do I preserve cockscomb?
Answer:

Air-drying is the best way to preserve cockscomb.  After harvesting cockscomb, strip the foliage from the stems.  Tie the stems into small bunches with rubber bands.  Hang the loose bunches upside down in a warm, dry, well-...

Question:
When should I harvest spaghetti squash?
Answer:

Harvest spaghetti squash when the fruit color changes from ivory white to golden yellow.  When harvesting spaghetti squash, leave a 1-inch stem attached to each fruit.  Store mature fruit in a cool, dry location.  

Question:
One of my trees has been damaged in a storm. How can I determine if the tree can be saved or should be removed?
Answer:

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...

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