Cedar Valley Arboretum & Botanic Gardens

Archive for January 2011

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Written by cedarvalleyarboretum

January 29, 2011 at 6:00 am

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Do you know Black Hawk County’s Plant Hardiness Zone?

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You have heard me praise the Arboretum’s e-newsletter in the past.  Our most recent edition – read full here http://www.cedarvalleyarboretum.org/pdfs/The%20View%20Volume%204%20Issue%201.pdf – is no exception.  Co-editor Pat McGivern wrote an incredibly informative article about plant hardiness zones and I wanted to share with you.  I know you will enjoy it as much as I did!

Thank you, Pat!

Would you like to receive the Arboretum’s monthly e-newsletter, The View?  Sign up here http://www.cedarvalleyarboretum.org/newsletter.asp.


Winter is the season we gardeners speculate and dream about our gardens for the coming year. In December and January we are deluged with bright and arty garden catalog mailings, that tempt us to try new plant varieties. But do we know what is truly expected to survive in our backyard through the winter a year from now?

Most gardeners have seen the United States Department of Agriculture (USDA) Plant Hardiness Zone Map (above) that is used as a standard guide to a plant’s cold tolerance. This map divides the United States and southern Canada into 11 zones, defined by a 10 degree Fahrenheit difference in the average annual minimum temperature, then subdivided by a 5 degree difference. The higher the zone number, the warmer the temperature. The original USDA map was published in 1960, sponsored by the United States National Arboretum and the American Horticultural Society (AHS), and was last officially revised in 1990, using temperature data gathered from 1974 to 1986. Using that map, Black Hawk County is clearly in Zone 4b, with average minimum temperatures of -20 to -25 degrees Fahrenheit.

In 2003, the AHS produced a draft revised map, using temperature data gathered from July 1986 to March 2002, which was a period of warmer winters than the last 1990 USDA revised map. That map would place Black Hawk County in the warmer Zone 5, with average minimum temperatures of -20 to -10 degrees Fahrenheit. However, this draft was not accepted by the USDA. As of January 2011, both the USDA and the National Arboretum websites are using the 1990 USDA map as current. The USDA website states that the USDA “is in the process of creating another version of the hardiness map using new mapping technology and an extended set of meteorological data.”

In 2006, the National Arbor Day Foundation used weather data from 1991 to 2005 to create their own plant hardiness zone map. The Arbor Day Foundation map also places Black Hawk County in Zone 5, with average winter minimums of -20 to -10 degrees Fahrenheit.

Are you confused yet? It remains the standard practice of most seed dealers and nurseries to label their products by the USDA plant hardiness zones (Black Hawk is then Zone 4b). You should be safe in planting perennials that are labeled for Zone 4, or for Zone 3 which is north of us. However, you can consider whether you wish to test the hardiness zone issue with trying a Zone 5 plant. Also consider the microclimate of where the plant will be placed. Will it be in a sunny location, sheltered from the harshest winds? Will it be in an area that usually has plenty of snow cover, to insulate the roots? Will you plan to mulch or cover the Zone 5 plant which may or may not be a bit tender for our next winter?

Good luck! As noted by author Michael Pollen in Second Nature: “We gardeners have always had trouble heeding Henry Ward Beecher’s sound nineteenth century advice, that we not be ‘made wild by pompous catalogs from florists and seedsmen.’ “

Written by cedarvalleyarboretum

January 27, 2011 at 6:00 am

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You Are Invited! Winter Planning Retreat – Sunday, January 29th

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Warm hearts, sharp minds,

Good food and friends,

Ideas and fun,

Our garden we’ll tend!

Come help us think,

Make plans and schemes,

The end result –

The arboretum of our dreams!

Winter Planning Retreat

Saturday, January 29

8:30 AM – 1:00 PM

Family Practice Center Board Room

Lower Level, Kimball Ridge Center

All Arboretum volunteers, donors, friends, and interested folks are welcome. Please e-mail office@cedarvalleyarboretum.org concerning your attendance.

Written by cedarvalleyarboretum

January 25, 2011 at 6:00 am

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Plant of the Week: Monkshood

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In college, I was required to take a course called Herbaceous Perennials.  It seemed like all we did that semester was memorize the latin and common names of the perennials widely grown in the Midwest.  I used all sorts of mnemonic devices and tricks when it came to studying for our identification tests.  And I was always releived to come across “freebies” like monkshood that were a cinch to remember.  On close inspection, the bloom looks like a helmet or hood.

Genus:  Aconitum

Other common names include friar’s cap, wolfbane, and turk’s cap.

Family:  Ranunculaceae

Other plants in this family include delphinium, meadow rue, clematis and buttercup.

The tall blue-purple spikes of monkshood could easily be confused with delphinium (the delphinium will have spurs on the bloom) on first glance.  The showy blooms grow 3-4 feet tall and perform best in partial shade and consistenly moist soil.  The above photo was take in October, making monkshood a lovely late summer-fall bloomer when other perennials are beginning to look ratty.  Monkshood foliage is similar to perennial geranium, with a deeply serated, palmate leaf.

Take  note: all parts of monkshood is highly toxic.  The plant has a long history – dating back centuries – of being used as a poison.

See you in the gardens.

Written by cedarvalleyarboretum

January 24, 2011 at 9:41 pm

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Written by cedarvalleyarboretum

January 21, 2011 at 6:42 am

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CVABG is on Wikipedia!

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Check it out!  The Arboretum now has a page on www.wikipedia.org the (very popular) free online encyclopedia.  To view, click on http://en.wikipedia.org/wiki/Cedar_Valley_Arboretum_%26_Botanic_Gardens or type in “Cedar Valley Arboretum & Botanic Gardens” in the search box on the main page, www.wikipedia.org.  This is a great resource to help educate people about our mission, gardens and programs.  As we learn more, we will update the page and make improvements.

 

See you in the gardens.

Written by cedarvalleyarboretum

January 20, 2011 at 6:00 am

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Plant of the Week: Yarrow

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Some plants never disapoint: they come up every year, grow with little fuss and bloom profusely.  Yarrow is one of those perennials for me.  The only negative comment I can make about yarrow is that every once in a while you can pick a weedier cultivar that spreads beyond its given space.  If that happens, I simply dig the overzealous plant up (you could also regularly thin if you want to keep) and try out another cultivar.

Genus:  Achillea

Other common names I found when searching included:  gordaldo, nosebleed plant, old man’s pepper, devil’s nettle, sanguinary, milifoil, soldier’s woundwort, thousand-leaf, and thousand-seal.  What a collection!  I have heard milifoil before, but none of the others.

Family:  Asteraceae (this family used to be called Compositae)

Other flowering perennials in this family are often easy to pick out with their daisy-like blooms.  Zinnia, coreopsis, chrysanthemums and black-eyed susans are also in the Asteraceae family.

The soft (sometimes hairy), feathery foliage is aromatic and if grown too thick, might develop fungal problems.  If you do start seeing fungal growth, simply thin out your perennial for better air circulation and make sure you are not overwatering.  Most yarrow cultivars have a prominent, flat-topped bloom cluster called an umbel.  The blooms are long-lasting in the garden and also make excellent dried cut flowers.  To encourage second blooming and refresh the perennial, consider cutting back after first bloom.  This will also discourage legginess in your plant.

The airy texture of yarrow make it an excellent companion plant to uprigth perennials like liatris and veronica.  Last summer I planted Achillea millefolium ‘Appleblossom’ in the Rose Garden as a rose companion plant along with artemesia, salvia, huechera and poppy.  Already I can tell it is going to be a great “filler” plant and look forward to seeing it take off next summer.

 

See you in the gardens.

Written by cedarvalleyarboretum

January 19, 2011 at 7:38 pm

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