Tuesday, December 18, 2012

Terrariums--Fun for Winter

This article comes from our very own Rachel Anderson.

As winter approaches, it is time for gardeners of the northern climates to move their passion indoors.  This can be more than the act of lugging the patio hibiscus to a safe spot in the living room, however; it is a chance to get up close and personal with the world’s flora in a way that is not possible outside.  Terrariums, in particular, afford a wonderful opportunity to get plants right under our noses so that we can clearly see the intricate details of their beauty.  They also help us understand how plants function and what it means to care for them.


Terrariums are enclosed, clear containers used for growing plants.  They provide proper conditions for establishing young or small plants or for allowing snipped parts of plants (cuttings) to take root and develop.  A bit of history:  the first known terrariums were invented in England in the 1850s by Dr. Nathaniel Ward, a physician interested in transporting tropicals across the sea and back to Europe for scientific study.  These vessels, made of glass and wood, came to be known as Wardian Cases.  Soon after that, the plant cases became popular as part of household d├ęcor.  They remain so today, as is evident with the plethora of do-it-yourself articles and online blogs devoted to terrariums as well as their availability in garden centers.

While terrariums do oblige as attractive living art, they offer other benefits.  Humans have an innate fondness for natural elements, and nature has the capability to improve health and well-being.  The presence of indoor greenery may have this effect as well and might help reduce stress and foster mental restoration, although more scientific research is necessary to confirm this*.  The healing power of a terrarium may come more from a person’s interaction with it rather than just the view.  Caring for one can take the place of gardening as a soothing pastime for those unable to go outside, whether they are stuck in ten feet of snow or they are recovering from an illness or unable to get around easily.  Children can also be put in charge of one—a great way to introduce the concept of personal responsibility and a fantastic avenue for learning about biology and natural systems. 

How do plants grow?  What do they require to live?  What is an ecosystem?  These questions can be explored informally through the study of a ‘garden under glass’.  Think of it as a magnifying glass:  a way to observe a miniature ecosystem and examine the principles of how it operates and survives.  Arguably, the most fascinating aspect of a terrarium is that it is self-sustaining.  It is a near example of a ‘closed system’ (no inputs or outputs).  For months at a time, it can thrive without receiving anything from the outside, save light.  The cycle of water, for example, is perpetual in an enclosed terrarium.  Water is transpired from the plants and becomes vapor, which eventually condenses on the sides of the container and finally trickles down to the soil again for the plants to absorb.  Remarkable!  It is like a tiny world that exists in a jar. 

Terrariums can transform a dreary December day into a gardener’s dream.  They can be used to get ahead of the growing season by starting some basil seeds or to bring the family together around a long-term project.  Many university extension websites offer tested advice on construction, plant selection, and aftercare, so one need not be shy to begin an indoor garden.  They also make thoughtful gifts.    
*See article Biophilia:  Does visual contact with nature impact on health and well-being? http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2760412/.

Monday, December 10, 2012

The Tree


by Liane Ellison Norman
Today they are cutting down
the old maple in the backyard,

a crew of three men, one
on a machine with long neck

that raises him into high branches;
one who has dismantled a part

of the fence that hugs the tree;
one wearing spikes, his chain saw

and other tools hooked to his belt;
high up, cutting thick branches

among dense leaves, working back
towards the scarred and damaged trunk.

The old maple has blushed faint
green in spring, glowed gold in fall,

spun lace in winter, runway and airport
for squirrels, birds—an owl one year—

a pair of woodpeckers who nested,
laid eggs: a starling killed the chicks.

But it's older than we are old
and might come crashing down.

It's being dismantled, the way
age dismantles, higher branches

cut first, then pruned back
until we can see from the sliced

raw trunk—twelve feet around—
an account of age. At dinner time,

three squirrels, tentative, peer
over the fresh stump,

perplexed that their whole world
has vanished.
"Tree" by Liane Ellison Norman, from Breathing the West: Great Basin Poems. © Bottom Dog Press, 2012. Reprinted with permission

Bur Oak Growing Study

Several bur oaks were recently planted in Waverly as part of a root-quality study designed to compare nursery growing methods and their adaptability to the landscape. Production methods being evaluated include direct seeding of acorns; traditional plastic containers (10gal); RootMaker™ root trapper bags (7gal); 12” RootMaker™ knit fabric bag; and B&B. Three samples of each have been planted - except B&B which will go in next spring. All trees are planted about 10’ apart in the existing city/school nursery. Growth rates will be recorded annually and root systems will be excavated by air-spade in future years to evaluate for things such as circling, girdling, lateral growth, radial spacing and depth.

15 Gal. traditional plastic containers.
10 Gal. Root Trapper(TM) grow bags.
Plastic container root system
Root Trapper(TM) root system

Planting site - Waverly school nursery.

Thursday, December 6, 2012


Gilman Park Arboretum, Pierce Nebraska

Check out this wonderful piece on garden pathways from Karma Larsen, written for the Nebraska Statewide Arboretum.

         “It was a lucky day for me when I discovered that I could put the lawn mower blade on the highest setting and cut a path through the tall grass that, at a stroke, transformed that sorry patch of grass and weeds into something altogether different—into a meadow... I don’t know exactly what it is, but that sharp, clean edge changes everything; it makes a place where there wasn’t one before.” from Michael Pollan’s Second Nature

            Garden paths are much more than just a way to get to a destination. They’re an invitation to take a closer look, a promise that there’s more to see. The initial goal may be accessibility—getting from the street to the house, from the kitchen to the vegetable garden—but the best pathways make us want to see what’s ahead. They draw us in and give a sense of order and structure to the landscape.
            In a small yard, carefully planned pathways can make it seem much larger and worth walking into. Larger landscapes become more accessible and inviting when a pathway reveals the way in. Pathways can be as simple as a mown path through taller grasses or perennials or as complex as a passageway through varying levels of hardscape materials with dramatic focal points scattered throughout.
            Practical considerations are important. If the goal is to get there quickly and easily (hauling groceries from car to house), a straight, wide path on a flat surface is probably best. If the destination is a bench under a big tree, a winding pathway through perennial beds is more appealing. Even less-travelled routes should be slightly elevated and have good drainage so they’re not muddy or underwater for parts of the year. Before installing or changing sidewalks in the front of your home, check with your local planning department and consider, too, whether you want the yard to be handicap-accessible.
            The width of the walkway is important. Heavily used walkways should be at least 4’ wide, enough for two people to walk comfortably side-by-side; lesser-used paths about 18” wide. Varying the width can make the path more interesting and can indicate “destination” points like patios, fire pits, benches or flower beds.
            For hardscaping, the options are endless: concrete sidewalk, stonework, treated lumber, gravel or crushed stone. When availability and expense permit, using materials in keeping with the building or the larger landscape strengthens the sense of place—limestone around a limestone building, wood chips through a forested area, grasses through a prairie, etc. If you prefer stone or other fairly expensive hardscaping but can’t afford it, one option is to set it into less costly paving materials like concrete or gravel to decrease the cost.
           Pathways need to be managed just like the rest of the landscape, so they should be able to accommodate mowers, snowblowers or any other equipment that might be needed.  Placing bricks or pavers flush with the ground on either side can eliminate the time-consuming task of edging.
          Turfgrass is best-suited for heavy foot traffic but some groundcovers can handle less-trafficked areas. Lawn alternatives for sunny areas include: buffalograss, blue grama, Carex, yarrow, basket-of-gold, snow-in-summer, winter creeper, creeping juniper, catmint, sedum, lambs ears and thyme. For shade or part shade:  Carex, goutweed, perennial geranium, sweet woodruff, deadnettle, pachysandra and periwinkle are good options.
November 2012 “In the Garden,” written by Karma Larsen

Ferguson Center, Lincoln

Thursday, November 29, 2012

Tree Planting Studies

Led by Graham Herbst, Community Forester based in Omaha, the Nebraska Forest Service recently implemented two tree planting studies to evaluate and help determine best growing and planting methods for better tree health in the landscape. The first study involved the planting of Swamp White Oak trees at Dodge Park in Omaha. Dodge Park is situated along the Missouri River and was heavily impacted by flooding in 2011. Swamp white oak was chosen to better tolerate any potential future flooding. The study includes trees grown by four different nursery methods: traditional plastic containers, Rootmaker(TM) grow bags (root trapper), balled and burlapped (B&B), and small seedlings started in square containers (Anderson pots). Trees were planted at proper depth and to try and simulate typical homeowner planting methods, so no extra care was given to root handling.  All trees will be monitored over time for growth rate and their root systems will be excavated by air spade in 5 and 10 years to evaluate root growth/health.

Planting locations at Dodge Park in Omaha

Tree grown in root trapper grow bag.

Tree grown in traditional container.

A second study was installed on UNL's East Campus in Lincoln. Part of the study includes evaluation of three nursery growing methods for Autumn Blaze Maple: B&B, traditional container and grow-bags. A second part of the study is designed to evaluate planting depth on tree health. Ornamental plum trees grown in grow bags were planted at varying depths ranging from 4" above grade to 12" below grade. All trees will be monitored for growth rate and their root systems will be excavated by air-spade in future years to evaluate root impacts.
Karma Larsen instructs Kendall Weyers to "dig over there."
Autumn Blaze Maple - B&B planting evaluation.
Finished planting of plum trees for depth study.

Sunday, November 11, 2012

Doing Battle with Cedars (to benefit oaks)

In the southeast corner of Nebraska, near the little town of Salem (a stone's throw from the Kansas border) grows a unique population of oaks known as dwarf chinkapin oak. Depending on the type of soil they grow in, this close cousin of the chinkapin oak (Quercus muehlenbergii), can grow as small, multi-stem trees or as sprawling shrubs, resembling American plum. This population of oaks is known far and wide by oak aficionados and is home to the national champion of the species!  The Nebraska Statewide Arboretum collects acorns from these plants nearly every year for nursery production as there is growing interest across the country for use of this species in the landscape. It is especially favored by wildlife enthusiasts. Most of the Salem population is found on dryer, rocky knobs, growing in association with relatively diverse mixed-grass prairie. The surrounding area is also home to some of Nebraska's most diverse deciduous forestland including hickories, redbuds, red oaks and many old and mighty bur oaks.
Oxymoronic: a large dwarf chinkapin oak (Quercus prinoides).
A plant this size may be a hundred years old or older!
Unfortunately, in recent years this area has seen an explosion in the growth of eastern redcedar, which are starting to choke out many of these unique oaks. Something needed to be done and recently a few of us from the Nebraska Forest Service spent a day on the property cutting out cedars. Armed with many chainsaws (and other saws) we happily cut and destroyed as many cedars as we could. We think we killed about 1,500. Many more still need to come out and we look forward to returning next year to continue the assault.
Cutting out eastern redcedars (Juniperus virginiana)

The Cutting Crew

 The beautiful day ended with a delicious chili and cornbread lunch prepared by the Stalder Family, long-time residents of the area and owners of the unique woodlands. A good time was had by all.
Mmmm. Chili and cornbread at the Stalder Farmstead.

Friday, October 12, 2012

Thinking about Our Trees II

As a follow-up to the last post regarding the benefits of trees, here are some thoughts and suggestions as we go forward in what will likely be a hotter and drier climate. The potential impact on trees is not completely understood, but I hope we're committed to keeping our community forests green and vibrant.

Lincoln's street trees are vital to community health and vibrancy.

One thing that the drought has helped make abundantly clear is that we can no longer take our trees for granted. For several decades, relatively abundant rain in our area has made it fairly easy to grow trees in including many marginal species that would otherwise not grow here. But there is a reason that prairie dominated this part of the world before settlement: the rain often goes away for long stretches at a time. Water is the limiting resource in this equation and for us to succeed in developing and maintaining a vibrant community forest we need to make that forest more resilient to the impacts of drought. A few suggestions:

1.       We need to be more thoughtful in picking the right tree for the right place. This is especially true for trees that will be expected to survive without any supplemental moisture. We’ve gotten a bit complacent in recent years and have selected many of our trees for ornamental appeal. Red maple, with its brilliant red fall color, is a classic example of a very popular tree that is not nearly as drought-tolerant as species like bur oak, red oak, coffeetree, hackberry, buckeye, Osage orange, pecan, walnut, etc.  

2.       Let’s think canopy! The community forest works best when there are lots of wide spreading shade trees coming together in a leafy embrace! Too many of our shade trees have been replaced by shorter-growing ornamentals.

3.       Plant trees close together and with other landscape plants to help separate them from the areas we mow. Trees that are grouped share a healthier soil (rooting zone) and are more drought tolerant than scattered individuals.

4.       Be smart with irrigation. In a typical summer (let alone a hot/dry summer), more than 3 billion gallons of water is sprayed on Lincoln’s landscape—primarily its lawns. Is this water being used efficiently and to aid in the best survival of our trees? It’s certain that there will be watering restrictions imposed during future droughts. Instead of designing irrigation systems primarily to keep large swaths of naked lawns green, we need to start thinking about irrigation as a tool primarily used to carry our landscapes through drought. One of the great things about trees is that most are actually quite drought-tolerant and just an occasional watering around them might be all they need to survive a severe drought.

5.       Speaking of irrigation, it’s probably time for a little tough love with more of our green space. Too many landscapes are now babied along with irrigation throughout the growing season. Unfortunately, when drought comes and watering bans are implemented, such landscapes are not able to survive on their own. Trees and other landscape plants that are forced to endure dry periods are better able to survive a severe drought. The trick is for us to find that happy medium.

Lincoln’s community forest is literally worth hundreds of millions of dollars (if not more). As with our built infrastructure—utilities, buildings, roads, etc.—our green infrastructure, especially trees, requires significant and ongoing attention, work and investment. And nearly anyone can help in their planting and care. To me it is abundantly clear that by helping to plant and care for trees, we are helping to make our communities much more livable. It starts in our own backyards and on the blocks that we live. The simple act of planting a tree—and then caring for those trees, is one of the best ways anyone can help make their community a more beautiful and prosperous place.  

Tuesday, October 9, 2012

Justin Evertson

Fall colors have arrived (and will fade quickly)! We've had a couple of hard frosts recently so the growing season is pretty much over. After a tough year of extreme heat and drought, a friend aptly described the frost as a "mercy killing". I concur.

Green ash and white ash along a street in Waverly.
As we leave behind one of the driest summers on record, many of us are left wondering what the future might hold for the trees of Lincoln and other Nebraska communities. This year’s drought has killed many trees across the state and it is almost certain that many more have been weekend and will likely die in the coming years as additional stresses take their toll. With increasing weather extremes (including the likelihood of more heat and drought) and with advancing diseases and insect pests such as emerald ash borer adding even more threats, it might be fair to ask: “Why should we work hard for trees with so many looming problems?” For me the answer is simple: because trees are still vitally important to our daily lives! The list of benefits that trees provide is extensive and would take a whole document to summarize. But there are three primary ones that we would NOT want to live without, or even have them marginally reduced: shade, stormwater absorption and beauty.

First, the shade that trees provide helps counter the urban heat island effect and can reduce a city’s temperature 5 to 10 degrees on a hot summer day. Not only is the community kept more comfortable, our energy costs are greatly reduced. Anyone paying for air conditioning is saving 10-20 percent or more on their electricity bill! The collective savings to all of us is in the millions of dollars. In terms of carbon storage and its impact on climate, trees are doubly beneficial as they directly store carbon in their wood and help reduce the release of carbon into the atmosphere by greatly reducing energy consumption.

 A second key benefit from trees relates to stormwater. Trees can capture and hold significant amounts of rain in their leafy canopies while their roots help soils more readily absorb moisture. It is estimated that collectively the community trees of Lincoln reduce peak stormwater flows by millions of gallons during rain events.  If our trees were suddenly gone, the amount of runoff from storms would likely overwhelm our drainage systems, greatly increasing flood damage, stream erosion and the pollution of waterways. The costs of improving our storm drainage systems to handle this extra water would be incredibly expensive.

Finally, trees are critical to our quality of life for the beauty and environmental benefits they provide. Over the years I’ve heard from many Lincoln visitors how impressed they are by all our large trees. We should not underestimate the value of this leafy canopy in attracting visitors, new residents and new businesses to town. And in the fall, when the air becomes crisp and our attention turns to the ritual of football, just think how much better it is thanks to the bright colors of the changing leaves. In addition to their beauty, trees provide cover and food for a wide variety of important birds and other wildlife. Without our trees we wouldn’t have cardinals, juncos, orioles, chickadees, waxwings and so many other colorful birds. And perhaps most importantly for me, without trees, I wouldn’t be able to enjoy pecan pie. How horrible!

In my next post I'll offer some thoughts about how we might better enable our community forests to survive a hotter future that will surely include more watering restrictions.

Tuesday, September 18, 2012

It rained!

It rained last week. Nearly 2". Thank goodness! It had been nearly 3 months since the last meaningful rain. Hopefully it will mark the start of a wetter pattern to benefit our landscapes (especially our trees!). The rainfall deficit for the year is still over 7" in many places across eastern Nebraska so we've still got a long way to go. Oh, but that glorious rain was so refreshing.

Now despite the relentless heat and drought of this past summer, many fall blooming prairie plants are showing off nicely including pitcher sage (Salvia azurea) and stiff goldenrod (Solidago rigida). Mother Nature knew what she was doing when the prairie evolved in this part of the world.

Pitcher sage (Salvia azurea)

Stiff Goldenrod (Solidago rigida)

Thursday, August 30, 2012

The drought continues... Dadgummit!

Dead Ginkgo in Waverly.
There is still no relief from the unrelenting drought of 2012. Last weekend brought an 80% chance of a good rain, and yet it just ended up spitting a bit. Which made me mad enough to spit. Since mid-June in Waverly where I live, we've only had a few light showers here and there totalling perhaps a half inch. A half inch of moisture for the entire summer!! I've never seen anything like it. The soil is cracking wide enough now that small dogs are disappearing! Much of the landscape is now a disheartening tan-brown and drab. I must admit that it's hard to stay enthused about things in the landscape this year. Many of the stalwart perennials are looking rough and there are very few blooms to punctuate the summer drabness. I often find myself thinking that it would be good if a frost came along and just ended the growing season and put us all out of our misery.

Dotted Gayfeather - Liatris punctata
Along with most non-irrigated perennials, many woody plants are really struggling or have just given up the ghost. Things that have caught my eye include young ginkgos, magnolias, Japanese maples, white pines, flowering dogwoods, and several types of viburnums. The most glaring struggle is perhaps revealed in the many brown and crispy burning bushes (Euonymus alatus) seen around Lincoln. They definitely have "burned" up this year. I don't mourn their passing as they're mostly out of place here anyhow.

But then I take a closer look at the landscape and am pleasantly surprised to see many plants hanging on, some producing flowers and fruits, and making me wonder how anything can survive with such little moisture. Species that have caught my eye in a positive perspective include most oak trees, our native burning bush (Eastern Wahoo - Euonymus atropurpureus), gray dogwood, most native grasses, several native perennials including ironweed and dotted gayfeather, stiff goldenrod, compass plant, etc. All is certainly not lost and Mother Nature is telling us something if we care to listen: "Work with me here folks and your gardens can flourish even in a bad drought year".

Ironweed - Vernonia baldwinii

Monday, August 20, 2012

Drought: Widening the Discussion

I would like to share an article printed in the Lincoln Journal Star, by Richard Sutton UNL professor and Landscape Architect, that takes a wider look at drought and how to make our communities more resilient and sustainable. 

Local View: Drought show's need to rethink Lincoln's landscapes.

Thursday, August 9, 2012


So far this year, on average, Nebraska has had 13.54 of precipitation (snow and rainfall) this year and the hottest year on record. I gazed outside at the parched landscape yesterday evening and chuckled at the weather man's comment "Luckily the thunderstorms moved on".  I certainly didn't feel very lucky.  Today Lincoln imposed mandatory watering restrictions.

The next few blog posts will be about drought.  I blogged earlier this year on how to water.  Today, Eric Berg, Community Landscape and Sustainable Landscape Program Leader for Nebraska Forest Service, helps look more on how to decide what to water and many other drought tips.

First a photo to inspire:

Ok, maybe not so much.  Depressing isn't it?

Maintaining Urban Green Spaces in Times of Drought

Abnormal seems to be the norm when it comes to recent weather events.  The landscapes we work with and manage have experienced a great deal of what we refer to in our shop as “climate weirdness.”  It is just not normal to go without measurable rain and with temperatures near 100 degrees for well over a month.  It takes a toll on us but it’s even harder on our landscapes.

Water restrictions soon may become mandatory for many communities and businesses.  To best use the potentially limited water resources we have on hand, how can we best manage landscapes to get through this period of drought? Here are some suggestions:

1.       One of the best things we can do is to prioritize efforts in the landscape. In terms of environmental, economic and social benefits, landscape priorities tend to run in this order: first trees, then shrubs, followed by perennials and ornamental grasses and, finally, turf grasses.  Before all of my turf friends run over to burn my office down, the point is simple—it’s a lot easier to replace turf than to replant established trees. 

2.       Newly planted trees need supplemental watering to survive. Normally we define “newly planted” as within the last five years, but I’m extending that to ten years given the current extreme drought conditions. Not only are trees planted within the last five years struggling, but even well-established trees that are 20 years old or more are beginning to show severe stress.

3.       Concentrate watering under the canopy of the tree and for a long enough duration that water is getting beyond the turf-rooting zone to a depth of 8-12” or more.  Tools to strategically do this include:  soaker hoses, gator bags (or similar products) and root feeders.  Root feeders are one of my favorite tools to efficiently water a lot of trees in a short period of time and direct the water right at the critical rooting zone 8”-12” below the surface of most soils. The other benefit with a root type feeder is that, by forcing water down into the rooting area, you are also increasing oxygen levels of the soils and creating more favorable growing conditions. This can be especially beneficial in high-use areas like parks where soil compaction is a limiting growth factor.

*A cautionary note is that all of these tools and methods have pros and cons.  For example, do not use gator bags if you are going to leave them on the trees empty with no water as they will act like little convection ovens on the tree trunk. Note also that while most of these watering systems allow for the incorporation of fertilizers, especially in the case of root feeders, that is the last thing you should do during a time of drought, since adding fertilizer could cause a flush of growth and further stress your plants with higher water demands.  Just keep it simple and get water down into the tree’s root system.

4.       Mulch / remulch all trees and planting beds to maintain an average 3-4” layer of well-seasoned, aged chips.  Mulch helps maintain soil moisture and reduces soil temperature but, most importantly, it keeps mowers and weed whackers away from tree trunks and valued shrubs and perennial beds. I recommend using “utility grade” chips, which are typically fairly large, thin chips produced from utility clearing operations, as opposed to double ground or grinder chips.  These larger chips typically last 1-2 seasons, layer well and do not mat together, allowing good gas exchange between the soil and atmosphere. Remember that low oxygen levels in soil are the most limiting factor for root growth in most urban soils. Keep away from mulch products such as river rock, pea gravel, etc. as they can dramatically increase soil temperatures.  Also avoid cypress mulch as it readily mats together and takes a long time to break down and add to the soil profile.

5.       This last recommendation is potentially the most important.  Think long-term solutions to water conservation practices and landscape management requirements.  Within the average life of a public or park landscape it will typically experience many periods of drought and extreme weather.  Observe what works and what does not and alter your landscape designs, plant selection and management input to take such things as drought into consideration.  My good friend Justin Evertson of the Nebraska Forest Service and Nebraska Statewide Arboretum has created a list of six items that, if implemented, will strengthen our landscapes against periodic, seasonal drought and, more importantly, against prolonged weather extremes:

§  Pick the right plants for the landscape – and think native plants! There are many, many drought-tolerant trees, shrubs, perennials and grasses that can be selected. Some of the best are our regionally native plants. Use more of those!

§  Don’t scatter trees or landscape plants across a landscape. Instead, plant trees and shrubs together in complementary groups and use them as anchors for additional landscape plantings – including perennials and ornamental grasses. Mulch them in mass and you’ll have a grouping of plants that are much easier to manage and have similar irrigation requirements.

§  Mulch around trees and shrubs – and mulch landscape plantings into larger beds separated from turf zones.

§  Limit the use of high-input turf grass to where it is truly needed – and begin converting parts of the lawn to more drought-tolerant species. Lawn development and care is a mindset: our vision should not be an emerald green carpet of turf rolling unimpeded across a community, but rather pockets of constant greenness where they make sense – where picnics, sports or other summer activities will happen. Otherwise plan for most turf grass areas to be compatible with summer brownness.

§  Think healthy soil! The more organic and biodiverse a soil is, the more drought tolerant it is. Organic soils better absorb and retain moisture. A healthy landscape begins with healthy soils.

§  Design irrigation systems wisely – and manage them wisely! Irrigation systems can be a good tool for landscape care, but they are also a primary source of significant waste of drinking water. There is no law that says an irrigation system should run every day or every other day. Irrigation systems should be seen as supplemental sources of water, not the primary source of water. We have a LONG way to go in this regard.

Monday, July 16, 2012

I never thought I'd sing the praises of silver maple (Acer saccharinum). This fast-growing species, common to river bottoms and floodplains throughout the central and eastern US, is considered by most tree enthusiasts (or tree snobs, whichever you prefer) to be a rather trashy tree not deserving of much attention or wide-spread planting. I've thumbed my nose at it most of my life and have literally cursed it many times as my neighbor's large tree drops its helicopter seeds by the millions clogging my gutters and leaving me with many hundreds of seedlings to pull every year. In fact I am now up to an estimated 7,384 seedlings I've pulled out of my yard over the last 20 years. Another concern with the species is its weak-wooded nature. It grows fast and big and is prone to significant damage in high-winds and ice storms and is a common culprit to power outages in such events. Over the years, many homes, vehicles and people have been damaged by falling limbs.  

Silver maple leaf - deeply lobed with prominent serrations and a "silvery" underside.

Tree huggers and a large silver maple in Ithaca New York. (credit Rich and Royal Hue) 

There is most definitely a lot to dislike about silver maple. And yet as I look around eastern Nebraska in this brutally hot and dry summer, the silver maple should be a much appreciated tree for the wide-spreading shade it casts. Look up at the canopy of any community forest and some of the most important trees helping to cool the air around us are the silver maples. The heat doesn't bother them and although they are a floodplain species, they seem to be very tolerant of significant drought. I doubt I will ever plant one myself, but in a summer like this I can sure appreciate the big silver maples that we do have - especially my neighbor's tree shading the south side of my house and property.

State Champion silver maple, Chautauqua Park, Beatrice

Yours truly - in the state champion silver maple.

Sunday, July 1, 2012

It's Hot Out There - Go Pin Oak!

Much of Nebraska has baked under record-setting heat in recent days (115°F in McCook!) and we haven't even reached the hottest days of the summer. Thank goodness for the shade trees working tirelessly to help keep our communities cooler! I like to run and on a recent noon-hour jog through a neighborhood near UNL’s East Campus, I couldn’t help but notice how important the shade trees were. Indeed, my jogging route in the 90degree heat was made manageable as I was mostly able to stay in the shade of some well-placed street trees. This particular hard-working neighborhood is blessed with a variety of species planted by forward thinking people in decades past. Species represented include bur oak, red oak, swamp white oak, green ash, Honeylocust, American elm, silver maple, Norway maple, and hackberry among others.

Street trees near UNL East Campus in Lincoln - on a hot summer day.
A shady oasis on a hot summer day!
One species that especially caught my eye during my run is pin oak as there are many large specimens to be found in this neighborhood. Though we rarely recommend pin oak for planting anymore because of its tendency to be chlorotic (yellow) on high pH soils, the reality is that some of the largest and most grand trees found in Lincoln and in other southeast Nebraska communities are the pin oaks. Over the years I’ve heard many visitors to Lincoln comment about its impressive trees. It is often the pin oaks that these people are especially impressed by.

A beautiful, relatively young pin oak.

Pin oak leaves.
Perhaps it’s time once again that we give pin oak the credit it’s due. Though still not appropriate for many sites (especially on newly constructed sites where the original top soil is gone) pin oak can be a good choice where a soil test reveals a loamy soil, rich in organic content and a relatively low pH (below 7). Pin oak grows fast and tall with an upright habit when young. It tolerates both wet soils and drought when established. It has good fall color and provides habitat to a wide-variety of birds, insects and other animals. And it loves the heat and humidity of southeast Nebraska. Thank you pin oak

Monday, June 25, 2012

Garden Tour!

It is always fun to get photos from Nebraska Statewide Arboretum, Inc. members and curators showing us how their gardens are growing.  A few weeks ago we got some photos from Steve Rothe, a NSA member from Omaha.  Steve is an ecologist by education, and professionaly plans and manages habitat restoriation projects. Steve says '' The primary intent of these gardens is native plants and their ecological value.  But I also want a pretty garden to prove you can have both.  But you can’t just throw natives in a nice bed and expect citified behavior; so the other intent is manageability, control, with open space and mulch.''  The result is a more "gardened" look, mixed in with traditional plants and even a few exotic annuals. Steve says that in these photos are at least 35 native species. We believe you, Steve!

Gardening with natives is not without challenges. Steve tells us that the garden "was was totally overrun by aggressive forbs. This bed had been filled with natives for 8-10 years and became an unmanageable, flopping tangle of big aggressive plants.  Last year I totally revamped it, adding soil amendments, removing most plants, relocating others, and adding some new ones."  He now has a bed dedicated to just the aggressive plants.  Steve warns "
Generally, stick to species from NSA or nurseries; there’s a reason some natives aren’t brought into the garden.  Or, dedicate an island bed to aggressives, and be prepared to weed them out elsewhere."

Improving the soil is important for success.  He gardens in native clay, "I finally bit the bullet and amended substantially with good effect." He tells new gardeners "Amend clay even if you’re a natives gardener with several inches of organic and friable materials."

On maintenance he adds " It is work. Mowing is faster and easier than gardening, but more boring."

Serviceberry (tree in backround)

Coneflower, White False Indigo, Poppy Mallow

Prairie Dropseed, Butterfly Milkweed, Liatris, Eupatorium, Helopsis

Blue Flax, Little Bluestem, Prairie Dropseed and Primrose

Steve's 'Island of Aggressors'

Friday, June 15, 2012

Drought Tolerant Trees and Shrubs

After a very dry stretch of weather, we were blessed with a beautiful rain last evening - a glorious 2" or more over most of the area. I was so excited that I went outside and started to dance - until the lightning and my embarrassed wife scared me back inside. Despite the wonderful rain, we all know that drought is a regular part of the climate story here in Nebraska and the dry weather will return at some point. Thankfully we have a wide-range of landscape plants at our disposal that are well adapted to our climatic extremes.  In fact, many of the prairie plants look their best when the weather and associated soil conditions stress them out a bit (little bluestem is the classic example). Here are a few of my favorite trees and shrubs that do a good job of tolerating drought conditions. Unless otherwise noted, these species are native to the region.

Bur Oaks in Bur Oak Canyon near McCook

Bur Oak (Quercus macrocarpa): If I could only plant one tree, it would be bur oak. It laughs at our weather extremes. This stand of native trees southwest of McCook attests to their tough nature.

Hackberry (Celtis occidentalis): This species provides yeoman's service to us year after year with very little love or fanfare from we humans.

Chinkapin oak leaves
Chinkapin Oak (Quercus muehlenbergii): is a very beautiful and underutilized shade tree able to tolerate an amazing range of climatic extremes.

Linden (Tilia americana): Only the worst of droughts will slow this tree down.
American Linden
Osage Orange

Osage orange (Maclura pomifera). On a hot, dry day, the shimmering glossy leaves of Osage orange are a welcome site.
Blackjack Oak
Pecan (Carya illinoinensis): Thought not quite as adaptable as its cousin the black walnut, pecan is still one of the best nut trees we can grow.

Blackjack Oak (Quercus marilandica) is a medium-sized, slow growing tree deserving of much greater planting. Its unusual leaves turn a nice red in the fall.

Gambel Oak (Quercus gambelii): This species is meant for the western half of our region where it can survive easily on less than 10" of annual moisture.
Gambel Oak

Boxelder maple (Acer negundo): This tree gets even less love than hackberry, yet will grow in just about any situation.


Fragrant Sumac
Fragrant Sumac (Rhus aromatica) loves the heat and rewards us with glossy leaves all summer and a nice red fall color.

Rabbitbrush (Chrysothamnus nauseosus): Primarily for western Nebraska, the gray-green foliage of this Xeric plant is unmistakable. Its yellow flowers are butterfly magnets in late summer.

American Hazelnut (Corylus americana) has proven to be very drought tolerant for me in Waverly. Love the apricot fall color.

Western Sandcherry (Prunus besseyi) is noted for its low, sprawling habit and light green foliage. It most definitely desires well-drained soils. Its cherry fruits are very tasty.

Clove Currant (Ribes odoratum): Though somewhat gangly as it grows, the clove currant is extremely tough and reliable and awards our efforts with very tasty fruits.

American Plum (Prunus americana): Is there anything tougher than the native wild plum?
Snowberry (Symphoricarpos occidentalis): This small, rounded shrub does not get nearly the landscape attention it deserves. It is only mildly suckering, has nice clean foliage and shows off with white fruits in late summer.

Roughleaf Dogwood (Cornus drummondii): This large suckering species is amazingly tough and adaptable and with a nice red fall color and attractive flowers and fruit.
Roughleaf Dogwood