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Extension > Yard and Garden News > December 2015

Wednesday, December 9, 2015

Nutsedge and Ornamental Sedges: What’s the Difference?

Yellow Nutsedge
Pacocha Landscaping Services, Inc.
Mary H. Meyer, Extension Horticulturist and Professor, University of Minnesota

Nutsedge is an aggressive long-lived weed (some consider it one of the world’s 5 worst weeds) in the genus Cyperus whereas the ornamental sedges are in the genus Carex and although some are aggressive, they can easily be controlled. Taxonomically, the ornamental sedges have separate male and female flowers, born separately along the flowering stem, whereas yellow nutsedge has perfect flowers that are in a terminal, fairly conspicuous umbel (upside down umbrella) cluster, see image below. Yellow nutsedge, Cyperus esculentus, and Carex spp. are both in the Cyperaceae family which is known for triangular stems and leaves in three ranks thus the rhyme: Sedges have edges, grasses are round and hollow right up from the ground.

When you pull up yellow nutsedge, you might get a small tuber often referred to as a nut at the end of the root, thus the common name ‘nut sedge’. This tuber is edible (the word esculentus means edible) and is grown for food in some cultures, earth almond is another common name. The tuber is a great source of stored food and helps the plant to grow, from as deep as 32 inches; it also makes translocation of chemical control difficult, as tubers can escape systemic chemicals, remain viable although dormant for as long as 10 years in the soil, and one plant can produce hundreds if not thousands of tubers in a year. Nutsedge has evolved to be a long lasting plant, and a great weed!

Photo by Jack Kelly Clark,
courtesy University of California
Statewide IPM Program
Yellow nutsedge prefers wet sites, but it will grow in many soil types and can flower when quite short at even 6-8 inches in height. The flowers are an umbel or cluster of several stems arising from a central point. Each flower has thousands of viable seeds, so removing flowers does help control the plants, but by far the small tubers and rhizomes are the primary means of propagation.

Yellow nutsedge is very aggressive; its pointy foliage can pierce black plastic and organic mulches. It often grows in patches with many plants quickly covering an area. For years I have had it in my community vegetable garden in Plymouth. While it is less common in cultivated areas, it still persists due to the heavy stand it makes each summer in the walkways between vegetable plots. Even walking on it does not slow its growth.

Control for yellow nutsedge is either vigilant cultivation and removal of plants, tubers, and rhizomes by hand and mechanical tilling; or repeated use of non-selective herbicide. Nutsedge is a difficult weed to control, but it can be managed.

View additional nutsedge images along with a list of appropriate herbicides.

Pennsylvania sedge, Carex pensylvanica
flowers in early spring in MN
and tolerates dry shady sites.
Photo: Mary H. Meyer
Comparison of Nutsedge and Ornamental Sedges

Nutsedge
  • Cyperus genus (perfect flowers in terminal clusters)
  • Shiny, yellow-green foliage
  • White leaf base
  • Triangular stems; 3 ranked foliage
  • Leaves have conspicuous midrib
  • Fast growing, Very aggressive
  • Small nut among roots
  • Yellow umbel of flowers

Landscape or Ornamental sedges
  • Carex genus (male and female flowers separate, often separated along stem)
  • Foliage color varies: striped, blue-green, green, coarse to fine texture
  • Leaf bases red, brown or green, not bright white
Sprengel’s sedge, Carex sprengelii
is an easy to grow native sedge in MN.
Photo: Mary H. Meyer
  • Triangular stems, three ranked foliage, but may be difficult to locate with much of the plant being basal foliage
  • Slower growing
  • No nut like bulbs at roots
  • Flowers brown or green, usually not conspicuous, often along stem



References



Lanini, W. T. and Wertz, B. Yellow Nutsedge. accessed 4 December 2015. Penn State Extension. http://extension.psu.edu/pests/weeds/weed-id/yellow-nutsedge.

Shonbeck, M. Weed Profile: Yellow Nutsedge (Cyperus esculentus and Purple Nutsedge (C. rotundus). Organic Agriculture at eXtension. Accessed 8 December 2015. http://articles.extension.org/pages/66868/weed-profile:-yellow-nutsedge-cyperus-esculentus-and-purple-nutsedge-c-rotundus.

Uva, R. J. Neal, and J. Ditomaso. 1997. Weeds of the Northeast. Cornell University Press, Ithaca, N.Y.

Tuesday, December 8, 2015

Western conifer seed bugs and kissing bugs

Jeffrey Hahn, Extension Entomologist

A western conifer seed bug, a type of leaf-footed bug, is a common insect in Minnesota. It is fairly large, measuring about ¾ inch long, and is reddish brown with a few white markings. It is distinctive in appearance because it possesses leaf-like structures on its large back legs. People rarely notice this insect during summer as it feeds on pine trees.
Western conifer seed bug, a common, harmless insect in
Minnesota.  Note the leaf-like enlargement on the hind leg.
Photo: Jeff Hahn, UMN Extension

However, it is commonly spotted indoors during fall and winter as it searches for sheltered sites to spend the winter. It can accidentally enter homes through cracks and gaps, much like boxelder bugs and lady beetles. Fortunately, no more than a handful of western conifer seed bugs are usually seen at a time. They are a nuisance by their presence but otherwise are harmless. See also Nuisance invaders: birch catkin feeders, hackberry psyllids, western conifer seed bugs.

However, people recently have been confusing this insect with kissing bugs.  Kissing bugs are a type of assassin bug, belonging to the subfamily Triatominae. For this reason, they are also known as triatomines. These insects are large, about ¾ to a little over one inch in length and are dark brown or black in color with orange and black markings. Their head is narrow and elongate. Because of this, this group of insects is also sometimes called conenose bugs.

Kissing bugs do not occur in Minnesota.  They are potential
carriers of Chagas disease. Photo: Sturgis McKeever,
Georgia Southern University, Bugwood.org
Kissing bugs are nocturnal blood feeders on various vertebrate animals including humans. They get their name from their habit of biting people on the face (other areas of the body can also be bitten). Being bitten is bad enough but kissing bugs are known to vector Chagas disease, a potentially fatal disease.

Fortunately, kissing bugs do not occur in Minnesota. Nearly all kissing bugs are tropical or subtropical in distribution and are found in South America, Central America, Mexico, and a few areas in the southern U.S. All cases of suspected kissing bugs that have been recently received by the University of Minnesota have turned out to be western conifer seeds bugs. For more information on kissing bugs and Chagas disease, see the Centers for Disease Control and Prevention web page.

It is also possible to confuse a masked hunter as a kissing bug. Unlike the western conifer seed bug, a masked hunter is also a type of assassin bug, like a kissing bug but is in a different subfamily. Adults are dark brown to black, and also measure about ¾ inch long. However they are more slender in appearance than either western conifer seeds bugs or kissing bugs. Masked hunters are most common during the summer but can be occasionally seen indoors during winter. For more information see Masked hunters.

New online tool for choosing plants

A new version of the Plant Elements of Design plant selection program is now available from University of Minnesota Extension. Released September 1st, the program features close to 2800 woody and herbaceous plants, and approximately 3500 plant images. More plants and images are being added weekly. Users are encouraged to read the user manual and participate in the user blog. Links are provided in the program. Designed to encourage plant selection based on site conditions and design requirements, Plant Elements of Design is open to the public and free of charge. Visitors are required only to create a user name and password. To select plants, users identify site conditions (soil, light, zone, etc.) and plant characteristics desired (plant type, size, flower, texture, form, use, etc.), from drop-down menus and click search. A list of plants matching the criteria will be listed. Many plants have images and all images are downloadable. Desired plants can be exported to a spreadsheet to build a plant list. Individual plants data sheets including any plant images, can also be printed for future reference.

Contact: Julie Weisenhorn, Extension educator - Horticulture, weise019@umn.edu

Order the 2016 Minnesota Gardening calendar for a favorite gardener

Keep your thumb green all year long! The Minnesota Gardening calendar features stunning seasonal photos and monthly gardening and plant tips. It is produced by University of Minnesota Extension and the University of Minnesota Landscape Arboretum, so it contains the most reliable information around. More than a calendar, the Minnesota Gardening calendar highlights research-based information on healthy soil, growing vegetables in Minnesota gardens and composting. A kitchen compost bucket sticker is included to remind you and your family about what goes in and what stays out.  Visit http://z.umn.edu/mngardening to order from the University of Minnesota Bookstore. Buy one for your and one for a favorite fellow gardener in time for the holidays and the upcoming gardening year!

Tuesday, December 1, 2015

Holiday Cacti Care

Holiday cacti in full bloom
Christmas cactus (Schlumbergera bridgesii), Thanksgiving cactus (Schlumbergera truncata), and Easter cactus (Rhipsalidopsis gaertneri) do not have the typical requirements of most succulents. Although true cacti, they are epiphytic in nature, growing in the branches of trees in their native tropical forest rain habitats. The need for high humidity, bright but filtered light, and soil kept relatively moist most of the year sets these plants apart from the majority of cacti and succulents.
Read more ....

Q&A: African violet is wilted

Question: After being healthy for many years, my African violet leaves are still green, but suddenly wilted, limp and hanging over the pot. What has happened and what can I do - if anything -  to revive it?

Answer: Houseplants wilting can be due to several factors. Most common is either under or over watering, so check the soil. If it is very dry, water the plant and see if it revives. If the soil is wet, then remove the plant from the pot. Carefully remove the wet soil and check the roots for rot (brown - black soft roots), a common problem in over watered houseplants. Constantly wet soil in houseplants causes not only root rot, but also fosters fungus gnats, a fruit fly that thrives in wet soil. If a majority of the roots are still white or light-colored, prune off the rotted roots, and re-pot the plant in soil for African violets. You can water from top or bottom with water at room temperature or slightly warmer. Allow the plant to drain well.

Plants may also wilt from an excess of fertilizer build-up. Fertilizers are salts and can build up in soil and cause desiccation (drying) of the plant. You can see it as a white crust on the surface of the soil. Fertilize at half the recommended strength when you see new growth on the plant. Flush the plant occasionally with clear water.

African violets foliage may also be affected by sudden cold or freezing. If your plant was in a cold location or has been in a window that is drafty, the cold temperatures may have affected the foliage as well.

Resources:
Caring for Houseplants in Northern Minnesota - U of MN Extension
African Violets  - U of MN Extension
African Violet Care - Purdue University

Houseplants: Proper Care and Management of Pest Problems - NDSU
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