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Lawns, Gardens & Trees

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Radiant and reliable

Sedum is a fall-blooming perennial that thrives in North Dakota.

Autumn Charm™ sedumChrysanthemum is the superstar of autumn—no other flower can match its brilliance in the late season.

That said, there is nothing brilliant about a perennial that blooms for only one year. Many mums planted this fall will not survive our winter.

Why not grow a fall bloomer that thrives in North Dakota? Something that will bloom this fall—and next fall.

Sedum is one of the most drought-tolerant, low-maintenance, hardy plants available. It’s perfect for North Dakota and is especially well-suited for harsh, rocky soils. It’s no wonder it is nicknamed stonecrop.

Sedum has year-round appeal. In spring and summer, its thick leaves provide an attractive foil to other flowers. Once autumn arrives, its pink flowers command our attention while other flowers in the garden fade. You will notice that bees and butterflies are drawn to sedum blooms. In winter, birds hop on top of the flower clusters and poke at the seeds.

Sedum is a staple plant of every rock garden but it will grow in any well-drained spot. They are effective when planted in groups, along borders or as a large groundcover.

‘Neon’ is a very popular sedum. Its magenta blooms are absolutely brilliant. ‘Autumn Joy’ has been an attractive and consistent performer for decades. Autumn Charm™ is a sport of ‘Autumn Joy’ with variegated leaves (shown). Wow!

The latest series of sedum are the Sunsparklers®. These compact plants come in vivid shades of red, purple and green. The creeping, 8-inch-tall plants are adorned with deep pink flowers in autumn. They are hardy to Zone 4.

Fall is coming and chrysanthemums will soon be appearing at garden centers. Enjoy them, but also keep in mind there are more reliable fall-blooming perennials for us in North Dakota: sedums.

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. Photo courtesy of Bailey Nurseries, Inc. Additional photos are available in the August 23, 2015 edition of the NDSU Yard & Garden Report

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Grow your own gold

Fall-sown cover crops will add organic matter ("black gold") to your garden soil.

Healthy soilDo you want to improve the soil in your garden? Add organic matter. Organic matter is so valuable it is sometimes called “black gold” by gardeners.

The addition of organic matter will improve nearly every soil. In clay soils, organic matter breaks open the ground, allowing for better drainage and aeration. In sandy soils, organic matter helps soil to hold onto nutrients and water. Organic matter adds nutrients too.

You can add organic matter to your soil by sowing a cover crop now. These crops will blanket the soil and protect it from eroding over winter. Cover crops will capture nutrients deep in the soil and bring the nutrients near the surface for next year’s crop. Cover crops can collect snow, improve drainage and reduce weeds in the future.

Cover crops can be sown in any area of the garden that is finished producing vegetables. You can also sow between the rows of crops that are still producing.

At this time of year there are two strategies for growing cover crops:

Oats (Avena sativa) should be sown now. The oats will put on good growth this fall and die over winter. It will be easily tilled into the soil in spring or mowed and left as a mulch. This is a good option for land where you plan on growing early spring crops such as carrot, spinach and pea. Annual ryegrass (Lolium multiflorum) is an alternative to oats.

Winter rye (Secale cereale) can be planted anytime in September (the sooner, the better). Winter rye will grow vigorously this fall and begin growing again in spring. This is a good strategy for land that will be planted late in spring with warm-season crops (tomato, cucumber and squash). Mow and then cultivate the rye into the soil in early May. No-till gardeners can spray it with glyphosate in spring to kill it. Give it a couple weeks to break down and then plant your crops at the end of the month. Winter wheat (Triticum aestivum) is an alternative to winter rye.

Seeds are available from catalogs and farm supply stores. Sow oats at 4 oz., winter rye and winter wheat at 3 oz., and annual ryegrass at 2 oz. per 100 square feet.

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. The photo was made available under a Creative Commons license specified by the photographer: Natural Resources Conservation Service. This article was originally published in the NDSU Yard & Garden Report. Sources used for this article: Cornell University. 2013. Improve your soil with cover crops. Ithaca, NY; and Johnny's Selected Seeds. 2015. Cover crops comparison. Albion, ME.

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Our state tree is making a comeback

elmThe grand tree of North Dakota is making a comeback.

The arching branches of elms once lined our city streets like columns in a cathedral. The majestic trees provided rapid and comforting shade over our neighborhoods.

The invasion of Dutch elm disease (DED) changed everything. Discovered in Mandan in 1969, the disease has killed thousands of elms throughout our state.

What a great loss—and these losses continue as DED spreads.

There is hope. We’ve learned how to manage DED. Trained arborists can identify infected trees quickly and dispose of the wood before the pathogen spreads.

There has been amazing progress in the introduction of new elms that resist Dutch elm disease. Dutch elm disease actually came from Asia, and some Asian elms have developed genetic resistance to it. This includes the Japanese elm cultivar ‘Discovery’. It is hardy, drought tolerant, relatively short (35–40 feet) and has an upright habit.

The University of Wisconsin and Morton Arboretum (Chicago) have incorporated the DED-resistance of Asian elms into American elms and released ‘Cathedral’ and Triumph™, respectively. These trees retain the arching habit of American elms and the disease resistance of Asian elms.

Researchers estimate that less than 1 out of every 100,000 American elms is resistant to DED. In spite of those dismal odds, a few gems that resist the pathogen have been discovered.

Dutch elm disease destroyed a group of elms along the Wild Rice River near Fargo. In this grove of death, one tree stood tall and healthy. Today we call that tree Prairie Expedition® elm, with proven resistance to the disease. Look for this tree in your nursery (municipalities are buying as many as possible). Other American elms with exceptional resistance to DED are St. Croix™ and ‘Jefferson’.

No elm is immune to DED. Use varieties that resist DED and keep them growing vigorously. Vigorous trees fight disease better than weak trees. Train elm trees when young to prevent weak, narrow crotches.

For more information on growing elms in North Dakota, watch NDSU Researcher Greg Morgenson’s 2014 talk on new elm cultivars.

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. The photo was made available under a Creative Commons license specified by the photographer: Dendroica cerulea. This article was originally published in the NDSU Yard & Garden Report. Source used for this article: Gillman, J., C. Giblin, G. Johnson, E. Sagor, M. Reichenbach and G. Wyatt. 2014. Elm trees – Dutch elm disease resistant varieties. Univ. of Minnesota: Twin Cities.

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Restore the monarchy

Gardeners can support the restoration of monarchs in North Dakota by growing milkweed.

monarch on milkweedMonarchs in North Dakota are happy today. They are feeding and breeding in our flower-filled prairies and gardens.

Everyone loves monarchs for their bright orange wings and gentle habits. I invite you to take a closer look at this insect and you will find a true marvel of nature:

No other insect on earth can match the migration of the monarch. In late August, the monarchs of North Dakota begin a round-trip pilgrimage to Mexico covering over 5,000 miles. They will soar in the skies like hawks, gliding 25 miles or more a day. Remarkably, they will arrive to the same villages and even the same trees their great-grandparents visited the year before.   

Did you know monarchs can scare away predators that are over 100 times their size? Imagine that! They gain these powers by eating and storing toxins from milkweed in their bodies. Many birds, lizards and other predators have evolved to avoid monarchs due to these toxins.  

Monarchs are amazing creatures but also very fragile. Their populations have declined by 80% over the last 20 years. This is due to many factors including the loss of overwintering sites in Mexico. In the USA they have lost breeding habitats due to agricultural expansion. The development of herbicide-tolerant crops has led to major increases in herbicide use and eliminated milkweed patches growing in pockets of farm fields where it once grew abundantly.

We can restore populations of monarchs by growing ornamental milkweeds (Asclepias spp.) in our gardens. Swamp milkweed is shown above. Monarchs cannot survive without milkweed. They lay eggs in milkweed, eat milkweed as caterpillars for its nourishment and protective toxins, and consume milkweed nectar as butterflies. 

Besides growing a few milkweeds, try to reduce the unnecessary use of poisonous insecticides. These chemicals threaten monarchs, pollinators and other beneficial insects.

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. The photo was made available under a Creative Commons license specified by the photographer: Brad Smith. This article was originally published in the NDSU Yard & Garden Report. Source used for this article: Oberhauser, K. 2015. University of Minnesota Monarch Lab. Univ. of Minnesota: Twin Cities.

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First impressions

The first fall colors are on display. A look at Hot Wings® tatarian maple.

Hot Wings® tatarian mapleThe first colors of autumn are beginning to show and they are brilliant! The seed pods of Hot Wings® tatarian maple are blazing.

Selecting trees for fall color is a challenge for us in North Dakota. The finest trees in autumn, including most maples, struggle here. Our soils are too dry and alkaline.

Tatarian maple is an exception.  It tolerates even our harsh soils and is hardy throughout the state.

Its seed pods (samaras) appear as fiery red wings. These wings contrast beautifully against the deep green foliage. Magnificent!

Tatarian maple is a small tree, growing only about 20 feet tall and wide. Its upright, spreading habit makes it an outstanding accent tree in small yards. Hot Wings® is a selection of tatarian maple noted for its radiant seed pods, vivid fall color, and strong tree structure.

If you love maples, get an analysis of your soil. If your pH is acidic to near neutral (approx. 7.2 or below), you can grow the superstars of autumn: red and sugar maples.

Superior red maples include Northfire® and ‘Northwood’. Fall Fiesta® and Northern Flare® are great sugar maples admired for their gold and orange colors. Autumn Blaze® has red maple heritage and is the leading Freeman maple.

For more information, watch the presentation on Hardy Maples for North Dakota Landscapes by NDSU Woody Plants Researcher Greg Morgenson. 

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. Photo courtesy of Bailey Nurseries, Inc. Article was originally published in the NDSU Yard & Garden Report

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Perfect perennials

Ornamental grasses are easy to grow and look attractive all year

'Karl Foerster' feather reed grassNorth Dakota is a land of prairie grasses. Our soils and climate are made for growing grasses. That’s one reason why ornamental grasses are perfect for us. They are loaded with other great features too:

Ornamental grasses are easy to maintain. They rarely need watering or fertilizing. Just cut the plants back every spring—that’s it!

They have almost no pest problems. Insects or diseases rarely bother ornamental grasses. Believe it or not, deer don’t like them! That’s too good to be true!

They grow fast. Many grasses will grow up to their mature height, even up to 8 feet, within two growing seasons.

They look good all year. You’ll enjoy a changing canvas of color from the emergence of tender grass in the spring to a display of roughened textures and brilliant colors in fall and winter. As a bonus, their seed heads attract lively and colorful birds to our yards.

‘Karl Foerster’ feather reed grass is one of the most popular perennials grown today (see photo). Plants grow 5 feet tall and provide a striking vertical dimension to flower beds. Its carefree habit has made it a staple in low-maintenance landscapes. Other popular feather reed grasses include ‘Overdam’ and ‘Avalanche’, each with eye-catching variegated leaves.

‘Northwind’ switchgrass was awarded the prestigious Perennial Plant of the Year award in 2014 (‘Karl Foerster’ won in 2001). ‘Northwind’ has olive-green foliage and a sturdy, upright habit. Another showy switchgrass is ‘Shenandoah’, noted for its stunning burgundy leaves and plumes in autumn.

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. The photo was made available under a Creative Commons license specified by the photographer: daryl_mitchell. More photos are available in the NDSU Yard & Garden Report

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Fireblight

A common disease of crabapples and other species. Learn about the cause and the multiple control methods.

Fireblight is a common disease of many Rose-family species in North Dakota.  The list of hosts includes apples, crabapples, hawthorn, mountain-ash, cotoneaster, pear and others.  Fireblight is caused by a bacteria that enters the tree via succulent tissue or through fresh wounds.  The recent storms that have been rolling through our region have resulted in perfect conditions for this disease to flourish.

The most common symptoms (see below) are dead branch tips with leaves still attached, curved over at the tip into a ‘shepherd’s crook’.  There is usually a sharp dividing line between living and dead tissue, and in some cases a sunken canker will be found here.  The bacteria can be found even further into the living tissue which is very important when treating the problem.

fireblight, crabapple, Valley City

A heavy infection of fireblight on a crabapple in Valley City, ND.

Dormant-season pruning is the best option for treating fireblight.  Locate the dividing line between living and dead tissue, and go back at least 8-12” into the healthy wood before pruning at a branch connection.  If there are just a few dead branch tips, they can be pruned out during the growing season but it is critical to sterilize the pruning tool between cuts to minimize the potential for spreading the bacteria to new wounds.  Pine Sol® or a 20% bleach solution can be used as sterilizing agents.  Both are corrosive to metal, so rinse and oil pruning tools when finished.  Chemical treatments in the spring can help prevent the disease from establishing, and copper-based fungicides as well as streptomycin are labeled for this purpose.  Follow all label directions and treatment recommendations.

fireblight, canker, margin, crabapple, Valley City

Canker margin on fireblight; living tissue is on the left and dead tissue is on the right.  Pruning should be at least 8-12" into living wood and should occur at a branch connection.

One additional way to prevent fireblight is plant resistant varieties of the host species.  Fireblight ratings of several edible apple varities can be found at: https://www.ag.ndsu.edu/pubs/plantsci/hortcrop/h327.pdf.  More information on the basics of tree pruning is available at:

https://www.ag.ndsu.edu/publications/landing-pages/gardens-lawns-trees/pruning-trees-and-shrubs-h1036

-Joe Zeleznik

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Spring Fever Gardening Workshops Set

Spring Fever Garden ForumsIf you want to learn about selecting trees or growing a productive garden, the North Dakota State University Extension Service's Spring Fever Garden Forums can help.

NDSU Extension is offering the series of workshops for gardeners across the state Monday and Tuesday nights, March 23, 24, 30 and 31, from 6:30 to 8:30 p.m. Central.

A team of 12 university experts will present information on timely topics in gardening and landscaping and then answer your questions.

Topics also include landscaping with flowers, pruning shrubs, attracting pollinators, growing fruits and herbs, and protecting plants from diseases.

The presentations will be made to a live audience in Fargo and delivered to more than 40 Extension sites across the state. Gardeners may attend at these sites or go online and participate in the live presentations on their home computer.

"More than 1,000 gardeners will participate in this mega-event," states Tom Kalb, Extension horticulturist. "It is a great opportunity to learn of gardening trends and see the latest research from NDSU."

The workshops are free of charge. For a full list of presentations and to register, go to http://www.ag.ndsu.edu/springfever.

Written by Tom Kalb, Extension Horticulturist. Edited by Ellen Crawford, Information Specialist.

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Gift ideas for gardeners

These gifts will bring happiness to your friends and family.

'Appleblossom' amaryllisThe holidays are here and so are the busiest shopping days of the year! Gardening is America’s #1 hobby and you can bring happiness to others by giving gardening presents. 

Amaryllis is a great holiday gift. It is showy and one of the easiest plants to grow. A quality bulb company can offer extra large bulbs that will bloom this year and in future years too. Always remember: the bigger the bulb, the better.

The following is a brief description of more gift ideas:

Lightweight gardening hoses are getting popular. Good pruning tools are always appreciated. A pocket knife is a handy gift. Solar-powered gardening pots are popular—they glow at night!

A new shovel, spading fork or hoe will be appreciated by a true gardener. A garden cart can help your friend move plants and tools around their yard.

Nitrile garden gloves are very popular. Hand scrubbing lotions will clean and moisturize our hands (the most important gardening tools). 

We all need to eat more veggies. A juicing machine can help us to get all the servings we need for a healthy diet. A dehydrator can convert our garden produce into nutritious snacks.

Thermometers, soil thermometers and rain gauges provide valuable information to a gardener.

Gnomes and other garden statuary are risky gifts, but sometimes these gifts bring the biggest smiles!

When all else fails, a gift certificate to a local garden center or a gardening catalog will put a smile on your friend’s face.

Happy holidays!

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. This article is an excerpt of a story published in the NDSU Yard & Garden Report, November 15, 2014. The photo was made available under a Creative Commons license specified by the photographer: Liz West.

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Sparkling jewels

Crabapple fruits add sparkling color to the winter landscape.

Red crabapple fruit in winterCrabapple trees have dropped their leaves and most have dropped their fruit, too. This litter creates a mess. That’s unfortunate. These fruitless trees will look unremarkable all winter long. That’s really unfortunate.

Why not select a variety with persistent fruit? Some crabs hold onto their fruits through much of the winter, adding sparkles of red and gold in the landscape. These fruits will also attract songbirds, adding another dimension of life and color to your home surroundings.

Red Jewel™ is renowned for its display of bright red fruits during winter. ‘Donald Wyman’, Sugar Tyme®, ’Prairfire’ and Sargent are other outstanding red-fruited types.

If you are looking for something different, ‘Snowdrift’ and ‘Professor Sprenger’ have orange fruits and the yellow fruits of Harvest Gold® are absolutely fascinating.

The next time you look for a crab, don’t focus on its spring flowers—these last for a couple weeks. Instead, consider how the tree looks during winter—this lasts for five months. Consider a crabapple with persistent fruit.

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. Published in the NDSU Yard & Garden Report, November 15, 2014. The photo was made available under a Creative Commons license specified by the photographer: Leah Grunzke.

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