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Rhonda J. Ferree


Rhonda J. Ferree
Former Extension Educator, Horticulture



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Rhonda Ferree's ILRiverHort

Rhonda Ferree's Horticulture Blog
Invasive Plants and Plants of Concern
The covering on the forest floor on the Bartell streambank in Peoria is almost entirely made up of garlic mustard.  Photo credit:  Adam Davis
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Plants That Inhibit Other Plants

Some plants don't seem to play well with others. In particular, a few plants release chemicals to try to keep other plants from growing too near. This botanical war tactic is known as allelopathy. Excerpts from University of Illinois Extension State Master Gardener Coordinator Sandy Mason's The Homeowners Column blog explains this further....

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Naughty, Nasty, and Simply Annoying Plants

See YouTube webinar on this topic. University of California Ranking System Dermatitis: Plant's sap may cause a skin rash or irritation. Major Toxicity: Plants may cause serious illness or death. Minor Toxicity: Ingesting plant may cause minor illnesses such as vomiting or diarrhea...

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Hummingbird moth on honeysuckle vine on May 7, 2012
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A Tale of Two Honeysuckle Vines

Vines add vertical beauty to a garden. Fast growing honeysuckle vines are easy to grow. Their intoxicatingly wonderful floral fragrance attracts hummingbirds, bees, and hummingbird moths. The story of these two honeysuckle vines is a lesson in using native plants. The Japanese honeysuckle ( Lonicera japonica ) was brought here from East Asia because of its fragrant and beautiful...

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Morning glory (Ipomoea sp.)
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Vicious Vines

Vines add vertical beauty to a garden. Although most vines are desirable, some can viciously choke out other plants with their aggressive behavior. Let's look at four examples. The first two examples are annual plants, meaning that they germinate new plants from seed each spring and then die each fall. Morning glory ( Ipomoea sp.) is a good example of a beautiful annual...

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Ornamental Pear

PERILOUS PEARS by Jason Haupt

Each year I am more distressed by the number of volunteer ornamental pear trees I see growing in fields, roadsides, and other places where they shouldn't be. This is yet another example of a plant that has escaped cultivation and become invasive. Below is an article written by my colleague Jason Haupt, Extension Educator in Energy and Environmental Stewardship. In recent years, one of t...

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Bush Honeysuckle Increases Tick Numbers

Now is a great time to remove invasive bush honeysuckle. Not only are bush honeysuckle invasive to native woodlands, new research shows that they also can increase the spread of tick-borne diseases. Bush honeysuckle are upright shrubs that grow 6 to 15 feet tall. Their dense growth habit is a favorite of deer and other small critters that ticks feed on. A University of Wisconsin study f...

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Garlic Mustard
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Invaders of the Weedy Kind

I have been battling some difficult and very invasive weeds this summer in my yard. A new weed in my gardens this summer is prickly sida ( Sida spinosa ), also called prickly mallow. This summer annual has a yellow flower and prickles at the base of each leaf. So far it is mainly in my herb garden so I wonder if I brought the seed in on a new plant somehow. The other rela...

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Wild parsnip (Pastinaca sativa)

Wild Parsnips

Parsnips are not only a root vegetable, but also a common weed in Illinois. Unfortunately, wild parsnips also cause allergic reactions in some people. Knowing how to identify wild parsnips can help prevent skin problems later. Wild parsnip is found growing along roadsides and in non-crop areas. It is typically two to five feet tall and has a yellow flower. Parsnip is closely related to...

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Beware of Dangerous Carrots!

While on a recent motorcycle ride with my husband Mark, I saw a lot of plants in the carrot family Apiaceae growing along roadsides. One of my favorite vegetables is the very edible carrot, but unfortunately the carrot family has a number of dangerous, poisonous plants in it too. The first two dangerous carrots I'll cover are stomach poisons, which means they are poisonous if eaten....

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Poison Ivy has leaflets of three while Virginia Creeper has leaflets of 5 or more.

Leaves of Three, Let It Be

A re your summer outings followed by days of itching discomfort? Knowing more about poison ivy and how it grows might help you avoid rash problems later. Remember the old adage, Leaves of Three, Let It Be! Poison ivy grows in various locations and many different environmental conditions. It is in fencerows, under trees, and in ornamental shrub and perennial plantings, probably...

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Burning Bush
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Burning Bush Becoming Invasive

Burning Bushes are very common landscape plants grown mainly for their intense fall color. Unfortunately, burning bush are becoming a plant of concern for many of us as we watch it reseed and invade nearby natural areas. I have two very large burning bush in my yard that were planted by the previous owner. The one growing in full sun usually turns a bright red in the fall, while the other one...

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Hummingbird moth on honeysuckle vine on May 7, 2012
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The Good, the Bad and the Lovely Plants: Free Webinar Series

University of Illinois Extension Horticulture Educators addresses Garden Biodiversity with a free webinar series called "The Good, the Bad and the Lovely Plants." Illinois horticulturists and gardeners revel in interesting plant characteristics but do not want to cultivate plants that disrupt the biodiversity of our natural Illinois landscape. Cultivating the biodiversity of plants in the Illi...

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Avoid Oriental Bittersweet!

Each year I seem to battle more and more difficult and very invasive weeds on my property. These include honeysuckle, garlic mustard, burning bush, and bittersweet. Oriental bittersweet is quickly invading my landscape beds. This plant seems to grow everywhere and spreads very quickly. Although it has beautiful orange fall fruit, birds and other animals disperse the seeds to other locations. I...

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garlic mustard
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Garlic Mustard is Invading Our Woods!

I first wrote about garlic mustard in 2001. Since then, this dreadful weed has gotten even worse. Many hundreds of man-hours and dollars have been spent trying to prevent it from choking out more of our native wildflowers. Garlic mustard, Alliaria petiolata, is not a weed to take lightly; if you have it, control is imperative. In Illinois, the plant behaves mostly as a biennial....

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Ornamental Pear
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Callery Pears Becoming Extremely Invasive!

Although ornamental flowering pears are beautiful in the spring, they have several severe problems. Below is a portion of an article written by Sandy Mason, Extension Educator in horticulture based in Champaign, IL. Since this article was published in 2005, ornamental pear problems have escalated out of control with even many more municipalities banning their use. 'Brad...

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Hummingbird moth on honeysuckle vine on May 7, 2012
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Bush Honeysuckle – Loved and Hated

Honeysuckle flowers are popular and there is a certain nostalgia associated with this old flower. It's not that surprising then that a quick internet search retrieved over 100 song lyrics that included "honeysuckle," says Michele Weisbrook, University of Illinois Extension Specialist. My drive to work this morning was blessed with an abundance of flowers...and a husband...

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Fire Blight on Callery Pear

"Fire Blight symptoms were observed on several Callery Pears this past week," says Travis Cleveland, University of Illinois extension specialist. "The symptoms were more severe than those observed during the 2013 growing season." Fire blight is a bacterial disease that affects rosaceous plants. Apples, pears, crabapples, and ornamental pears are the most seriously affected speci...

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