Plant Profile: Kentucky Coffeetree (Gymnocladus dioicus)

When one thinks of the Great Plains, trees are often the last thing to cross one’s mind. Surprisingly this region is home to a number of species that have found their way into yards and parks throughout the United States. The honey locust, American elm, black walnut and silver maple are as common in front yards as they are along streams and patches of woodlands of the plains. One of the more beautiful native trees found in this region is the Kentucky coffeetree, a member of the legume family. Kentucky coffeetree can be found along the eastern portion of Kansas. The tree derives it name from a common practice among early Kentucky homesteaders of grinding the seeds to make a coffee-like drink.

Mature Kentucky Coffeetree (Wikipedia)

Though somewhat uncommon in landscape plantings, the coffeetree offers many ornamental attributes. A large tree, it can reach 60 feet in height with a 30 foot spread. As of March 2022, the Kansas Forest Service state champion Kentucky coffeetree, located at Fort Leavenworth, currently stands at 100 feet tall. As the tree matures, the bark forms scaly ridges with curled edges. In winter the ascending branches present a picturesque silhouette against the winter sky. Written descriptions have labeled the tree “clumsy” looking after the leaves drop. While young trees can appear awkward their first few years, mature specimens develop stout trunks and main branches, reminding one of their innate toughness and durability.

In spring the tree may be slow to leaf out, but the patient observer is soon rewarded with bipinnately compound, bright green leaves with dainty, ovate leaflets that give the tree a soft, fine textured appearance throughout the growing season.

The bipinnately compound leaflets

Kentucky coffeetrees are individual male and female trees. The botanical term for plants with male and female flowers on separate individuals is dioecious, a condition also found in Ginkgo, juniper, and Osage orange. Flowers appear in May and June as graceful racemes. The male flowers are somewhat inconspicuous and green-yellow, while the female flowers are somewhat larger and pale yellow-white. Both types of flowers are quite fragrant. Each of these flowers are favorites of pollinating insects.

Creamy white flowers in the spring (Wikipedia)

Fall color is often a subdued yellow and female plants will often produce a reddish brown pod filled with incredibly hard, round, slightly flattened seeds. The hard coats allow seeds to lay dormant in the ground for long periods of time until weathering and soil bacteria wear down the tough shell, allowing germination to occur if temperature and moisture are adequate. Professional growers often soak the seed in concentrated sulfuric acid to thin the coat enough for water and gas exchange (a dangerous practice for the average home gardener). Another option is to use fine sand paper to sand down the shells so several seeds will potentially sprout. Don’t sand too much.

Bean-like pods and seeds of Kentucky coffeetree

Due to the coffeetree’s large size and the sometimes “messy” pods from the female trees, it is often not the best selection for the average yard. However, it is well-suited to large open areas, along streams and in park settings. It is not particular about soil, but best growth occurs in deep moist ground. Drought tolerant, it experiences very few problems.

In the wild, small colonies of coffeetree can be found when new trees form from the root suckers. This is usually not a problem in the landscape if the tree is mulched and regular mowing occurs around the tree. Transplanting in most successful with small plants, because the tree develops a course fibrous root system that limits the transplanting success of larger trees.

In the Arboretum’s bird watch area, a small coffeetree is planted just below the big bridge.

I like good coffee. Lucky for us that our coffee supplies for drinking are more than adequate, but one should still consider this beautiful, tough native tree for your landscape.

Landscaping with Native Kansas Oaks

Filtered light coming through a stately open-grown burr oak.

There are many appealing reasons to consider landscaping with native Kansas oaks. Oaks are

  • long-lived with strong branches,
  • can grow to be large and stately,
  • provide welcome shade from the hot Kansas summer sun,
  • allow some filtered light to pass through to allow growth of understory vegetation, and
  • enhance the wildlife diversity in any landscape by attracting insects.

Native Kansas Oaks

Kansas is predominately a prairie state. Fire and grazing have helped keep grasses and wildflowers as the dominant form of vegetation for thousands of years. Kansas does, however, get enough precipitation to support trees, especially many drought-tolerant species of oaks. And when they are not being burned or grazed down to the ground on a regular basis, they can thrive here.

With the Rocky Mountain rain shadow influencing the precipitation map for Kansas, we have increasing bands of precipitation moving from west to east across the state.

Trees generally need more water than prairie grasses and wildflowers. Therefore, it is understandable that eastern Kansas climate is most hospitable for growing trees. The following Küchler Vegetation Map of Kansas confirms the association between greater precipitation and the historical presence of trees by the location of oak-hickory forests, oak savannas, and other timbered regions in the eastern part of the state.

The trees that thrive throughout eastern Kansas may also be able to grow further west into Kansas, but will be limited to locations near streams or urban landscapes where they can receive supplemental irrigation.

Using the fantastic recently published book, Trees, Shrubs, and Woody Vines in Kansas by Michael Haddock and Craig Freeman, I compiled the following table of the oaks native to Kansas. I have listed the 12 native oak species in order from most to least common in Kansas. I did this to serve as a guide to the species that generally have the greatest tolerance to drought conditions and that are therefore more likely to succeed even in the drier parts of the state.

Attracting Wildlife

Regarding the benefits of oaks I provided in the introduction, I want to expand a bit on the benefits of attracting wildlife.

Filtered light sustains understory vegetation

Oaks in general and especially more drought-tolerant oaks like burr oak allow more light to filter through its leaf canopy to the understory than other tree species such as elms and maples. As I describe briefly in a post about a local, large burr oak tree, burr oak savanna plant communities of Eastern Kansas were historically able to support diverse arrays of grasses and wildflowers under their canopy that promote a healthy ecosystem of biological diversity. Urban folks can follow this model and grow prairie-like native plant gardens under the canopy of oaks. This also helps explain why it is easier to grow turf grass in the filtered light conditions under an oak than it is under the shadier understory of an elm or maple.

Oaks – the best trees for supporting wildlife

Professor Doug Tallamy in the Department of Entomology and Wildlife Ecology at the University of Delaware is a big proponent of using native oaks to attract wildlife. His book Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens makes a strong case for using oaks to attract caterpillars, and subsequently birds that feed caterpillars to their young, to enhance the biological diversity of a landscape. His research shows that the oak genus (Quercus) attracts more caterpillars to its leaves, flowers, bark, acorns, and roots than any other genus of trees. In fact, this genus is so important to Tallamy that his most recent book The Nature of Oaks: The Rich Ecology of Our Most Essential Native Trees focuses entirely on the subject.

Five Favorite Oaks

While I think there are appealing components to all 12 of the native Kansas oaks, I have narrowed my focus for the purposes of this post to promoting five favorite oak species.

USDA maps denote the natural range of each species. A given tree may still thrive in say an urban area outside of this range when offered wind and drought protection from structures, other trees, and/or supplemental irrigation.
This 55′ wide by 45′ tall burr oak outside my office window is great example of how this species takes a wide-open stance when grown in full sun. The root structure cross-section drawing pasted proportionately below this tree was found in the Nebraska Conservation Bulletin Number 37.

Burr oak savannas were part of the focus of my graduate research and I simply love the majestic, strong-branched open-grown shape of this species. The shape and distinct look of a mature Q. macrocarpa specimen in winter is as interesting to me as its leafy green look during the growing season. It is bimodal in its moisture distribution, meaning it can survive in both dry upland conditions as well as low floodplain conditions. Thick, gnarly bark makes this tree more fire tolerant than most, and when top-killed, its taproot allows it to immediately re-sprout. The large acorn fruits (hence the Latin name “macrocarpa“) are food for many insects, mammals, and birds (e.g., turkeys and wood ducks). To appreciate the value of a burr oak to wildlife, click on this Illinois wildflowers link and scroll down to the impressive list of “faunal associations.” Burr oak leaves turn yellowish-brown before dropping in the fall.

The attractive ashy gray bark, toothy margined leaves and stately round shape of the drought-tolerant chinquapin oak make it an appealing landscaping tree. One-inch sweet acorns are a favorite food for many birds and mammals and the leaves turn yellow-orange to orangish-brown before dropping in fall. This species prefers well-drained soils but tolerates a variety of soil textures and moisture regimes.

Dwarf chinquapin oak only reaches a mature height of approximately 20 feet and certainly can be used in different landscaping scenarios than any of the four other medium to large landscaping trees recommended here. You may use it as a featured shrub or planted with many to form a screen. This species prefers sandy or clayey soils whereas the larger Q. muehlenbergii does best in calcareous soils. In spite of its small size, dwarf chinquapin oak can produce large quantities of acorns which along with the leaves and bark provide food for numerous species of insects, birds and mammals. This oak is known to produce underground runners to spread clonally.

Black oak is named for its dark bark color at maturity. It has a deep taproot with widespread laterals which make it a very drought-tolerant tree that is adaptable to a variety of soil types. It does especially well in sandy soils. As described for other oak species, black oak provides food for numerous insects, birds and mammals.

Shumard oak is a popular landscaping tree because of its strong branches, long life and red fall color. It is adaptable to a variety of soils and its acorns provide food for various types of wildlife including insects, birds, and mammals. Although its natural environment is along streams in Eastern Kansas, it is tolerant of drier areas further west in protected urban areas. A shumard oak I planted in my yard loses its leaves late fall, by around Thanksgiving.

Things to Think About

Tree size/location

When locating a tree, leaving room for the eventual size of the mature tree will save you or future caretakers time and money. Conflicts between growing tree branches and buildings, utility wires, city code street clearances, and branches of other trees can lead to tree trimming headaches, so consideration given to a tree’s height and spread is important. Also, the closer a tree is to a sidewalk or driveway, the more likely its roots are to alter the grade of and contribute to the cracking of that concrete.

How long will it hold its leaves?

Some oaks lose their leaves in fall, but others hold onto them until spring. I can think of a couple of reasons this may be important to you. If you like to do your leaf raking in fall, don’t choose an oak that holds leaves till spring. If you want your oak to cast shade in summer but not winter, be sure to choose an oak that drops its leaves in fall. For example, this may be an important consideration for a tree that shades a house in summer, but allows solar panels to work in the winter.

Oak leaves are slower to decompose

Know that oak leaves have higher tannin content than many other tree species, and therefore, take longer to decompose. I like to use all my tree leaves for garden mulch and since the oaks I’ve planted in my landscape are all pretty small still, this has not been a big concern. However, if you compost your leaves or have heard the myth that tannin-rich oak leaves will make your soil more acidic, read this article.

Slower growing trees still provide rewards

A common complaint I hear about oaks is that they grow too slow. Therefore, folks may opt for the short-term gain of quick shade provided by a poplar or silver maple instead of a longer lived oak. A poplar lifespan may be 30-50 years, a silver maple 50-100 years, and an oak 150-250 years. But what you gain in quicker shade with the poplar and silver maple, you give up in durability, attraction to wildlife, and passing along quality trees to future property owners. The above recommended oaks all would be considered slow to moderate rate growing trees. Do know that you can increase the growth rate of an oak with mulching, supplemental water, and fertilizer. Maybe it is the skewed perspective of an oak lover, but I would think that oaks even improve property value. And remember, a tree is planted for the next generation as much as it is for you.

Steps for Planting a Tree

This spring is going to be anything but normal.  I know that’s an obvious understatement.  All this social distancing has made me think of the many things I need to get done around my house.  Social distancing time may be beneficial and help me stop procrastinating.  My house needs to be painted.  I need to add a fresh layer of mulch on my front flower beds. Another thing I was thinking about was planting another tree. 

For those of you who are looking for things to do with your children who are home from school, planting a tree is a great activity to do together outside. And with the 50th Anniversary of Earth Day on April 22nd and Arbor Day on April 24th, there are many related online educational resources available to help talk about the importance of trees and caring for the earth.

So in that vein, here are the steps I take when planting a tree. 

Choose the right tree

I work from a short list of trees I know will grow well in our area.  Some of my favorites are: Caddo sugar maples such as ‘John Pair’ and ‘Autumn Splendor’, Shumard Oak, disease resistant crabapples, Shantung maple, and bur oak.  There are so many good options for our area, but make sure you are aware of the tree’s mature size.  This will affect power lines, crowding buildings and porches, and heaving sidewalks.  See our Native Plant Guide or recommended plants from KSU extension for other options.  

Shumard Oak ready for planting

Dial 811

We have all seen the cheesy commercials to “dial before you dig”, but the truth is it’s important to locate utilities.  It doesn’t cost anything.  You just give the location and then wait a few days for them to flag the area.  It is worth making the call rather than guessing while you’re digging. 

Locate the tree

Depending on the tree, some may be easy to find while others may take some time.  We recommend smaller trees that are ¾” to 1 ½’ caliper trees.  In our experience, these smaller caliper trees tend to root faster and acclimate to the site better than larger 2-3 inch caliper trees.  Plus, they are more economical and as I get older, I am less willing to wrestle with a 200 pound root ball than I used to be.     

Before Planting

As you look at your new tree in a pot or balled and bur lapped, you must find the root flare.  This is the point where the trunk widens to transition to roots.  If the root flare isn’t visible, you will need to remove enough soil until it is exposed.  This is a critical step to insure the tree is not planted too deep because this root flare needs to be slightly above the soil line.  Sometimes, nurseries heap two to three inches of soil on top of the flare, causing you to plant it too deep. 

Dig a proper hole

Dig and measure, dig and measure so you don’t dig too deep of a hole.  Make sure the root flare is a couple inches above the soil line.  The tree needs to sit on solid soil, not loose soil that will settle and move the tree deeper.  Make the hole two to three times the diameter of the root ball. 

Plant the tree

Before putting the tree in the hole, remove all wires, twine or anything else tied to the tree.  If you don’t, these ties and wire can girdle the trunk or branches and cause severe damage. 

Once the tree is in the hole, orient the larger branches to face south. The prevailing winds are from the south, which force branches to grow on the north side of the tree making it lopsided.

Once oriented, carefully remove the wire basket and cut circling roots from potted trees in two or three spots around the root ball.  This process will encourage new outward rooting of the tree. 

Back fill with the same soil you removed from the hole. Don’t amend the soil with something like peat moss, because you want the tree to immediately root into original soil, not some artificial environment. Trees planted into peat moss or amended soil have toppled over by wind because they just circled in that loose soil, never venturing out into our clay soils.  Don’t give them an option, force the trees to grow in our challenging soils from the start. 

There is no need to fertilize at this time either. Fertilizing forces growth that cannot be supported by the new root system.  If you need to fertilize, it is better to wait several years until the root system is more established.  I don’t add root stimulator either.  In my opinion, it is an added expense that doesn’t benefit the plant enough to justify the cost.    

Build a basin for watering

After the tree is properly back filled, I like to build a small basin around the tree. This will help with watering the tree, but also slowly settle as the back fill settles.  This basin can be mulched to help with cooling the environment, retaining moisture and controlling weeds.  Give it a good soaking at this time. 

Basin around an American Elm

Staking the tree

Most smaller trees will not need to be staked.  It has been proven that trees will establish quicker when left to move with the wind, which make the trunks stronger.  Larger trees will obviously need to be staked the first year, but stake only when necessary to keep the tree from toppling over until roots can anchor the tree on their own.  If you do need to stake a tree, we put one stake on the north side and two on the south side of the tree.  These stakes are evenly spaced around the tree.  Don’t use old garden hose but rather true tree straps around the trunk of the tree tied back to these stakes. After one year, remember to remove all of the stakes, wire and straps from the tree.

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Weeping willow with basin and stakes on bank of rain garden
Tree strap used for staking trees

Maintenance after planting

It is better to wait to do any pruning on the tree for the first year.  The only exception would be removing any damaged branches.  With the basin you have created around the tree, it makes it easier to water it thoroughly once a week for the first year depending on rainfall.  Keep in mind that it takes a year or two to develop an adequate root system to sustain a tree on its own without supplemental watering.

I have a placard at my desk with a quote from Martin O’Malley that says, ‘Reversing deforestation is complicated; planting a tree is simple.’  This post seems rather lengthy, but the process of planting a tree goes rather quickly once you get started. 

The Best Trees for Fall Color

‘The best time to plant a tree was 20 years ago. The next best time is now.’

– Chinese Proverb

 

For many reasons, fall is my favorite time of the year.  I love the cooler weather and changing landscapes.  This signals the end of another growing season, but there are still a few highlights to come. The beauty of the fall wildflowers like asters and goldenrods makes them stand out in a sea of grass.  The native grasses are at their peak with attractive seed heads and brilliant fall color.  It is also a time when trees begin to change, developing shades of red, orange, yellow, and tan.  I know winter is coming, but the crescendo of our gardens is fun to watch.

Native Blackhaw Viburnum (Viburnum prunifolium)

How do trees develop fall color?

Fall color in trees is a result of a complex process of removing the green pigment, chlorophyll, from the leaves, which allows the other pigments to be seen.  For instance, carotene and xanthophyll (carotenoids) are yellow pigments that are produced all year long with chlorophyll.  With the shorter days and cooler fall temperatures, chlorophyll production is slowed and the green color slowly disappears revealing the yellow pigments that have been there all year long.  Green ash and ginkgo are good examples of trees with nice yellow fall color.

Other trees produce red and purple pigments called anthocyanins, which tend to cover the yellow pigments present in leaves during the fall.  As the fall season progresses, the increased sugar content in these leaves works to intensify these reddish-purple leaves.  American ash, shingle oak and shumard oak are nice trees with red fall color.

In trees with a combination of carotenoid and anthocyanin pigments, an orange fall color develops.  Sugar maples, smoke trees, and sweet gum trees are wonderful examples with orange fall colors.

Some of our trees have no vibrant fall color, but rather the leaves turn to tans and browns. This is caused by tannins in the leaves, which accumulate as the chlorophyll is removed from the leaves.

Fall color can be a little different every year.  Plant genetics, and environmental conditions make subtle changes from year to year fun to watch.  Each year, there is a unique beauty in the landscape that should be savored, enjoyed and not taken for granted.

White oak

My Favorite Trees for Fall Color

Shumard Red Oak (Quercus shumardii)

This oak tree will reach a height of 40-60 ft. with a nice rounded-pyramidal habit.  It is a stately tree that produces a wonderful range of colors from deep red and maroon to dark oranges.  Fall color can be quite variable from year to year depending on environmental conditions.  Other oaks worth trying: shingle oak, white oak and black oak.

Sugar Maple (Acer saccharum)

Sugar Maples and many other maples are the quintessential tree for fall color. In Kansas, sugar maples are relatively slow growing but worth the wait as a mature tree can put on quite a fall display.  They reach an ultimate height of 40-50 feet tall and equal spread.  The bright red, orange and yellow leaves appear in October and last for many weeks.  Try the cultivars, ‘John Pair’, ‘Autumn Splendor’, ‘Table Rock’, ‘Flashfire’, ‘Oregon Trail’ or ‘Legacy’ for the most consistent fall color each year.

Table Rock Sugar Maple

Bald Cypress

This is not usually recognized as a tree with exceptional fall color, but when the fine leaves turn reddish-brown in the fall, it is striking.  We have planted Our specimens near the pond where the “knees” can develop. The pyramidal habit reaching 50-60 feet tall make it a majestic tree for certain situations. It is certainly worth a try.

Bald Cypress fall color

Others worth noting:

  • Viburnum rufidulum
  • Viburnum prunifolium
  • Cotinus ‘Grace’
  • Betula tremuloides ‘Prairie Gold’
  • Sassafras
  • Ginkgo ‘Autumn Gold’
  • Carya cordiformis
  • persimmon

We are already seeing signs of fall here at the Arboretum.  Fall color starts in September and ends in November with peak coloration sometime in October.  Cool night temperatures above freezing, calm winds, and sunny days will make the colors more intense.  So, even though it’s not New England, let’s enjoy the beauty of fall.

Sugar Maple






Osage Orange: A Historical Living Fence

It is so common around this part of the country that we take it for granted, but the Osage Orange (Maclura pomifera) is a very special tree, valuable to both farmer and wildlife, and integral to the agricultural history of Kansas.

Osage Orange, of course, is the tough, thorny tree of Central Kansas hedgerows.  To many people, it’s also known as hedgeapple, or simply hedge.  It grows so well here, even escaping out into fields and wood lots, it seems that it must have been here before the pioneers arrived.

IMG_2239

Osage Orange Hedge

 

Actually, Osage Orange did not occur naturally in Kansas: its original range was limited to parts of Texas, Oklahoma, Arkansas and Louisiana until it was brought in for windbreaks and living fences in the 1880s.  At that time, many miles of hedge were constructed by planting thousands of young Osage Orange trees closely together in a line.  Many hedgerows still can be seen dividing fields and pastures today.

Once established, the thorny young trees were pruned to promote thick, bushy growth.  The term “Horse high, bull strong and hog tight”, used to describe the Osage Orange, simply means that the hedge rows were pruned so that they were tall enough that a horse would not jump it, stout enough that a bull would not push through it and woven so tightly that even a hog could not find its way through.  Hedge is tough!

IMG_2243

Hedge thorns

 

When barbed wire was invented, the hedge fences were torn down or left to grow on their own as shelterbelts, field borders and windbreaks.  Along with its attributes as a hedge, Osage Orange has long been valued for the strength and durability of its wood.  Ironically, barbed wire is usually tied to a hedge post to make pasture fences.

The Osage Indians, from which the tree’s name is derived, were noted for using the wood to make bows.  It is reported that Osage Orange bows were so highly regarded by Indian tribes to the north that they were willing to offer a horse and blanket in trade for one.

Anyone who has ever been around the trees in the fall is familiar with their “oranges” (or “apples”). These softball size fruit are produced on the “female” trees, while “male” trees have only pollen producing flowers and do not bear fruit.

Available Osage Orange (Maclura pomifera) cultivars include ‘Wichita’ and ‘Whiteshield’ (vase-shaped). Use fruitless and thornless cultivars only.

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Hedgeapples

This common tree is often overlooked, but is a valuable and iconic component of our Kansas landscape. The resilient Osage Orange holds the soil well, and provides cover for wildlife and a windbreak against strong winds. Though it may not function as a fence for modern farmers, its presence here reminds us of the ingenuity and tenacity of our farming ancestors on the Great Plains.

 






Which Trees Should I Plant in Kansas?

The best time to plant trees and shrubs is in the late fall and early winter before the ground freezes. With proper watering and maintenance, newly established plants will get settled and acclimated to their new environment.  By developing roots this fall, these plants will increase their chance of survival through the first growing season next year.

The Hesston City Tree Board did a street tree inventory several years ago for the entire city and found that there are too many Silver Maples, Siberian Elms, and Pin Oaks.  These three species represent 31% of the town’s total tree population.  The recommended percentage of any one tree would be less than 5% of the total population.  Insect and disease problems can decimate a single species (such as Dutch elm disease in American elms or pine wilt in Scotch Pine).  Tree planting diversity by the citizens of Hesston can help improve the overall make up of the population and bring it back into balance.

At the time of this survey, the City of Hesston and the Tree Board developed a five year planting strategy to promote diversity for future planting.  This strategy was intended for Hesston, but will work for nearly every community in the state.  Some of their recommendations and mine are contained in the following list.  These trees are native to eastern or central Kansas and adaptable to most of the state.

Which trees should I plant in Kansas? Try a few of these:

Bur Oak (Quercus macrocarpa) – A very large broad spreading tree (70’ x 70’) with long smoothly lobed leaves.  Mature trees come alive in the fall with squirrel activity as the acorns mature.  Excellent as a shade tree, but give it space.

Northern Red Oak (Quercus rubra) A large tree (60’ x 60’) with a rounded growth habit in youth and maturity.  The seven to eleven lobed lustrous dark green leaves turn a russet-red in fall.

Shingle Oak (Quercus imbricaria) – Pyramidal in youth and eventually becoming broad and rounded at maturity (50’ x 50’).  The leaves are unlobed and lustrous dark green, turning yellow brown to russet-red in fall.  Leaves are persistent though winter.

Shingle oak

Shingle oak

Post Oak (Quercus stellata) – A dense-rounded tree (40’ x 40’) with shiny green leaves that are roundly lobed.  Hard to find in the nursery trade, but worth the effort.

American Linden, Basswood (Tilia americana) – A very large (60’ x 60’) upright pyramidal to broadly open tree.  The gray smooth bark, fragrant creamy-yellow flowers in late spring, and dark green leaves make American Linden a nice choice as a shade tree.

Sugarberry (Celtis laevigata) – A hackberry with smooth gray bark and large (40’ x 40’) rounded growth habit.  Fruits have a sweet date-like taste and are loved by birds.

Hackberry (Celtis occidentalis) – Widely adapted to many areas throughout the state, hackberrys can withstand all Kansas can throw at them.  Upright to pyramidal in habit (40’ x 40’) with rough deeply furrowed plate-like bark.  It is a larval food source for the question mark, comma, hackberry, tawny emperor, snout, and morning cloak butterflies.

Catalpa (Catalpa speciosa) – Very adaptable to a wide range of soils from wet to dry.  It has an open irregular crown (50’ x 40’) with large heart-shaped leaves.  The flowers, which appear in May and June, are quite showy.  Worth growing, even though it is thought of as a messy tree that drops its leaves and seed pods.  Don’t all trees do that?

Persimmon (Diospyros virginiana) – Tough oval rounded tree (40’ x 35’) with fragrant white blueberry-shaped flowers in May and June.  The real treat comes in the fall when the edible fruit ripens and the foliage takes on colors of yellow to reddish-purple.

American Hophornbeam (Ostrya virginiana) – Rare in the nursery trade, this tree deserves to be used more because it makes a great street tree.  Pyramidal in youth becoming rounded with age (25’ x 30’), it has deep green, sharply serrated leaves that turn yellow-brown in fall.

American Hophornbeam

American Hophornbeam

These trees are examples that will increase the tree diversity in your neighborhoods and landscapes.  For more information on these or other trees for your area, contact your local tree board, local horticulture extension agent, or visit the arboretum.  We have examples of many of these trees growing at the arboretum.  I would be happy to answer any questions you may have.

Remember – diversity is the key to success!






Where Have All the Conifers Gone?

The Kansas landscape can be stark and lifeless at certain times during the year.  In the winter, the hues of brown are seen everywhere from the leafless deciduous trees to the native grasses in the prairies and ditches.  This harsh landscape is only broken up or punctuated by evergreens.

During the growing season, they melt into their surroundings, but are exposed as the landscape changes in the fall and winter.  Early settlers noticed their green forms and incorporated them into shelter belts and home landscapes to breathe warmth and life into a drab and dreary panorama.

Sadly, these conifers (cone-bearing seed plants) are under siege.  They are being decimated by a variety of diseases that really have no reliable cure.  Whole shelter belts have been lost to this onslaught.  Trees that are 50-100 years old are gone in just a few years.

Even here at the arboretum we have felt the pain of losing evergreen trees.  35 years ago, when the arboretum was originally planted, these diseases were not known and certain conifer varieties were readily available and a more diverse plant selection was not installed.  But those species have not proven resistant to disease, so we now have holes in our landscape where mature trees have died.

Taylor Juniper (foreground) Canaertii Juniper (background)

Taylor Juniper (foreground)
Canaertii Juniper (background)

 

So what is the solution?  I think that the final solution is diversity in the landscape.  Just like you diversify your stock portfolio to spread out risk, we need to diversify the evergreens and conifers we include on our land and around our homes.  Whole shelter belts have been lost because they included only a few species.  Once infected, the diseases spread through the whole line of trees and result in large holes that are filled with other non-desirable species.

The extension service suggests that diseased and dead trees be removed immediately and destroyed either by fire or chipping.  The stumps also need to be removed to a depth of at least 6 inches below the surface.  Pathogens that spread the diseases overwinter in the dead trees and emerge or are released by April to infect other hosts.

Southwestern White Pine

Southwestern White Pine

 

The arboretum has been experimenting with a few conifer species that seem to be hardy and less susceptible to disease.  They are Upright Chinese Juniper (Juniperis chinensis), Easter Red Cedar (Juniperis virginiana), which is the only evergreen native to the state of Kansas with cultivars ‘Canaertii, and ‘Taylor’, Black Hill Spruce (Picea glauca var. densata), Southwestern White Pine (Pinus strobiformis), Pinyon Pine (Pinus edulis), Lacebark pine (Pinus bungeana), and Arizona Cypress (Cupressus arizonica).  This list is not extensive.

Pines like Ponderosa (Pinus ponderosa), Austrian (Pinus nigra) and Scotch (Pinus sylvestris) have been taken off the recommended tree list because they are so prone to disease.  I would highly encourage you to visit the Kansas Forestry Service website at www.kansasforests.org .  Once there choose your region to view a full list of recommended trees for your area along with other informative publications.

Arizona Cypress

Arizona Cypress

Arizona Cypress

Arizona Cypress

 

Full descriptions of these trees can be researched on the internet or you can come to the arboretum and view them in person.  For certain species the time will come when they are completely eliminated from the landscape barring a cure.  Healthy trees need to be properly pruned and given plenty of air circulation.

You can do everything right and still lose a tree.  Replant with a diverse variety of species so your whole landscape will not be open to widespread devastation again.  There will be other diseases that come, but diversity will give you the edge.






Five Oaks for the Kansas Landscape

The strongest oak of the forest is not the one that is protected from the storm and hidden from the sun. It’s the one that stands in the open where it is compelled to struggle for its existence against the winds and rains and the scorching sun.  – Napoleon Hill

If you live in Kansas long enough, you really begin to appreciate trees.  They endure heat and extreme cold along with persistent wind.  Months without rain are common, but so is the occasional soaking rain that saturates the soil.  Trees in this part of the world need to be resilient.

Folks in areas of the country that have an abundance of trees often take trees for granted.  Trees grow easily, but not here.  A good shade tree in Kansas is a luxury.   They need to withstand the rigors of the climate.  To sit under a mature tree on a warm afternoon, enjoy the blue skies and sip your favorite cool drink is a special experience.

Here are five oaks trees that are “plains tough”.   (This is my list, but there are over 10 species of oaks native to Kansas and several other non-native varieties that are equally tenacious.)

OAK TREES FOR KANSAS

1. Bur oak

When I go fishing along the Cottonwood River, I can’t help but notice the huge Bur oaks (Quercus macrocarpa) stretching out their limbs over the river.  West of Hesston, there is one that has a span of over 150 feet.  It is quite a specimen.  This native oak of the eastern two-thirds of Kansas is one of the most adaptable hardwood trees in Kansas.  Generally, it is slow growing, but in the right conditions it can grow two to three feet a year.  Mature height is 50 to 80 feet tall and with a spread from 40 to 60 feet. The Bur oaks don’t typically have great fall color, but it is very sturdy and problem-free.

Bur Oak

Bur oak

 

2. White oak

As part of my horticulture classes at Kansas State University, I had to learn the names of many different plants on campus.  One of the trees I remember the most is a white oak (Quercus alba) on the east side of campus.  It is a beautiful tree with great fall color.  This stately tree stood about 60-70 feet tall with a spread of at least 60 feet.  I would love to have that white oak in my back yard, because I know that it would be there for generations.

White oak

White oak

 

3. English oak

The Kansas state champion English oak (Quercus robur) is in Kinsley.  If it can grow in Kinsley, it can grow anywhere in the state.  It is native to Europe, but a versatile tree in Kansas.  Typical growth is 30 to 50 feet in height and 30 to 40 feet in spread.  Leaves are dark green throughout the year.  They eventually turn brown, but stay on the tree much of the winter.  This tree adapts to most soil types, including heavy clay.  Ours at the arboretum puts on good growth each year – one to two feet.  Give it room to grow and you will be rewarded with an excellent shade tree.

 

4. Shumard (red) oak

The fastest growing member of the red oak family is Shumard oak (Quercus shumardii) making it a great choice for the home landscape.  Its native range is eastern Kansas along moist streams and upland rocky hillsides.  It is quite adaptable to a wide range of soil conditions.  The fall color can be incredible.  It is recommended that you choose your tree in the fall when they are coloring because the species can be variable in fall color intensity.  Shumard oaks are more tolerant than other red oaks of urban areas and challenging sites.

 

5. Shingle oak

Our shingle oaks (Quercus imbricaria) this fall have been spectacular.  The red fall color was more brilliant than in previous years.  The color fades, but the leaves will persist through most of the winter.  Speaking of the leaves, they are unusual among oaks.  They don’t have lobes, but are smooth along the margins.  It is a great form that can thrive in drier conditions.   They grow 40 to 60 feet tall and spread 30 to 50 feet.

Shingle oak

Shingle oak

 

Planting an oak today is like leaving an inheritance to future generations.  Choose wisely!