ALDER (common)

• Fast growing oval shaped tree maturing to 50' X 40'. Tree prefers plenty of moisture but will tolerate dry, compacted urban soils as well. Has moderate tolerance of salt and will grow in full sun or partial shade. Very attractive branching, leaf shape and nut-like fruit that hangs on through the winter. Does not attract wildlife and is not messy. Very good choice for the Front Range and transplants easily.

  Common Problems:

  Environmental:

  No significant issues. Alders will tend to grow multiple trunks and can be left to do so for screening or ornamental purposes. They can also be pruned to a single leader.

  Diseases:

  None of significance. However, in Europe a disease similar to the potato blight that has caused significant death among the Alders.

  Pests:

  Aphids and Leaf Miners are sometimes found in low pressure populations but are typically not an issue.

  Cultivars:

  Several available.‘Aurea’, golden yellow leaves; ‘Fastigiata’ - narrow, upright form; ‘Laciniata’ leaves not as deeply lobed, vigorous growth; ‘Pyramidalis’,upright or columnar form to 50 feet tall, 25 feet wide.

  History & Use:

  The earliest fossils date back to the miocene about 18 million years ago. It has been traditionally grown for timber and firewood. It is used extensively for soil stabilization along river banks and for soil reclamation projects after such disturbances as mining or logging. They are a nitrogen fixing species meaning they make the soil significantly more hospitable to other tree species wherever they grow.

  Not native to North America. Escaped early landscapes and has established well, especially along waterways and other disturbed wet sites where it will propagate easily and form pure stands or thickets. It can be harvested for excellent furniture and cabinet grade lumber (Alnus rubra reaching 120 feet in height). Very attractive, clean and smooth, grain which lends itself to a very stable final product.

  Alders tends to pull minerals from the soil and store them in the cells of their woody architecture. The bark is known to be used for treating burns and infections because of its chemical make up.

• Apple (malus)

  A highly cultivated tree growing medium to fast and generally maturing to a round crown of 35' X 25'. Prefer moist loam soils but tolerate alkaline, clay, dry and a bit of salt fairly well. Very showy spring flowers and edible fruit make this an attractive planting choice. There are many many cultivars of apple available. So many that we will discuss only edible apples here. See Crabapples for non-fruiting or flower specialty varieties.

  Common Problems:

  Environmental:

  Structure pruning is very important from early on and should be done according to what the trees purpose will be. If the apple will be harvested the tree should be pruned to reduce height and encourage thick limbs in order to make picking practical and allow the trees architecture to support the heavy fruit. Prone to sucker sprouting at base and in the root zone of trees. Sunscald is common on newly transplanted trees, wrap trunks for 2-3 years.

  Diseases:

  Fireblight, Powdery Mildew and some other fungus problems are common with these trees. Plant Resistant varieties available from most nurseries. Control through pruning and/or chemical applications is often recommended. Apple Rusts do occur with Hawthorn and Juniper as the alternate hosts but it is an uncommon occurance.

  Pests:

  Aphids and Wooly Aphids are a regular nuisance with these trees. The fruit is prone to Codling Moth which is very common and controlled with a pesticide treatment in the Spring.

  Cultivars:

  Many are available: You can check them out at Creekside Nursery

  History & Use:

  Apples have been hybridized over many thousands of years from an almost inedible small fruit into the many varieties we enjoy today. The wood is excellent for burning and if you can find a straight solid trunk it is a beautiful furniture grade lumber. Also used for wood turning.

• American Ash (White Ash) (Fraxinus americana)

  A medium growth tree reaching 60-90’X50’ with an elliptical canopy and preferring medium soil moisture. Has a tough time in clay soils but tolerates it with adequate water. Fall and winter watering is particularly important. Is somewhat drought tolerant. Produces copious amounts of seeds which can be messy but keep the birds fat. Vivid yellow to brown fall leaves can be spectacular on some trees.

  Common Problems:

  Environmental:

  Girdling roots are common and should be watched for and pruned, if necessary, at planting. Sunscald is very common on the southwest trunk of young trees (0-3 years) and recent transplants and should be wrapped from November thru March to avoid the damage. Must be pruned as it grows to establish good branch structure otherwise it will likely develop poorly and fall apart in wind and snow storms.

  Diseases:

  Ash are effected by a number of leaf fungi that are usually not bad enough to warrant chemical control. Just rake up and dispose of infected leaf tissue when it fall s to the ground. Some cankers can be found on trunks and branches but usually only on stressed trees. Verticillium Wilt attacks stressed trees and will cause severe branch dieback or whole tree death in some cases. Ash ring spot is a virus that causes some twig dieback but it is rare and often minor.

  Pests:

  Susceptible to a number of insects especially Ash Borer and Aphids. Ash borer will damage the trunk and kill the tree if left untreated for many years. Aphid populations can be heavy but do little to stress the tree health, they are however, unsightly and the honeydew can be a nuisance on walks and cars. Ash Flower Gall attacks the developing flowers in early spring leaving an unsightly brown crusty ball and often stunting leaf and twig growth for the year.

  Cultivars:

  ‘Autumn Purple’ is the most common White Ash in use. It is smaller, seedless and has an attractive deep purple foliage in the fall. Several others available as well.

  History and Use:

  Very popular for tool handles and the wood of choice for the baseball bat. Also used in flooring, furniture, and lobster traps. Very hard wood with an appealing grain when finish sanded.

• ASH ( American)

• Growing to 60’X40” in an oval shape this tree can be very fast growing with adequate watering but typically it is a medium growing tree. A hardy selection and a top choice for city street trees because of its high ph and salt tolerance in soils. It has brown to yellow fall leaves. The females produce an incredible amount of fruit which can be a nuisance.

  Common Problems:

  Environmental:

  Girdling roots are common and should be watched for and pruned, if necessary, at planting. Sunscald is very common on the southwest trunk of young trees (0-3 years) and recent transplants and should be wrapped from November thru March to avoid the damage. Must be pruned as it grows to establish good branch structure otherwise it will likely develop poorly and fall apart in wind and snow storms.

  Diseases:

  Ash are effected by a number of leaf fungi that are usually not bad enough to warrant chemical control. Just rake up and dispose of infected leaf tissue when it fall s to the ground. Some cankers can be found on trunks and branches but usually only on stressed trees. Verticillium Wilt attacks stressed trees and will cause severe branch dieback or whole tree death in some cases. Ash ring spot is a virus that causes some twig dieback but it is rare and often minor.

  Pests:

  Susceptible to a number of insects especially Ash Borer and Aphids. Ash borer will damage the trunk and kill the tree if left untreated for many years. Aphid populations can be heavy but do little to stress the tree health, they are however, unsightly and the honeydew can be a nuisance on walks and cars. Ash Flower Gall attacks the developing flowers in early spring leaving an unsightly brown crusty ball and often stunting leaf and twig growth for the year.

  Cultivars:

  ‘Marshall seedless’, ‘Summit’, ‘Patmore’, ‘Cimmaron’, ‘Newport’ are the most common. Summit is very popular but caution is needed as it tends to grow multiple trunks and branches making it very weak and highly susceptible to failure in winds as it matures. It is very difficult to “prune” into a strong structure.

  History and Use:

  Very common street tree. Wood can be used in furniture and flooring.

• Aspen

• Grows fairly quick with adequate water to 18'X45'. Aspen do well in the clay soils but water is the key and they are very thirsty trees. Winter watering is crucial.

  Common Problems:

  Environmental:

  Roots like to surface and sprout making it ideal for fields and open spaces where this won’t be an issue. Wood is weak and tends to break easily under wind or snow loads. Pruning can help but planting with maximum distance to targets such as paths, structures and streets is best. Because this tree actually reproduces though root sprouting it is ideal to let as many sprouts as possible grow and replace the older stems (trees) that will die.

  Diseases:

  Trunk cankers and leaf fungus (blights) are fairly common. Watering and fertilizing are the best deterrents. An anti-fungal or fungicide spray applied as the leaves begin to form in early spring will often reduce or eradicate leaf blights for the season.

  Pests:

  Aphids are often present but pose little threat to overall health. Oyster scale and polar borer are often a problem as a tree ages or if it is stressed. Oyster scale can be treated by scraping off or with a systemic insecticide. Poplar borer is difficult to treat.

  Cultivars:

  'Pyramidalis' Bolleana (white) poplar, A smaller more upright and narrow variety.

  Upright European Aspen

  Growing quickly to 45’X15’ in a narrow columnar form this tree requires high soil moisture and regular watering. It does well in our clay soils and even in turf. It has flakey bark and yellow fall leaves.

  History and Use:

  This tree is found throughout the Rocky Mountains and is a major attraction in the autumn as the foliage turns to a vibrant yellow. A very popular landscape choice with a bad rap for its tendency to have problems with pests and diseases. This is true but almost always due to cultural issues like insufficient watering practices.

  Used in rustic furniture making.

• Paper birch (Betula papyrifera)

  A medium size tree 40’X25’ with an elliptical shape growing at a medium rate and liking high moisture in a cool soil. Yellow in fall.. White flaky bark is chalky and exfoliates with horizontal black lines and eyes common. Trunk typically remains golden brown for the first ten years or so of life. Fall and winter watering very important.

  Common Problems:

  Environmental:

  Susceptible to sunscald and leaf scorch. Avoid planting with direct exposure to the south and west sides. Watch for girdling roots at planting and root prune if necessary.

  Diseases:

  Diseases are rare along the Front Range.

  Pests:

  Bronze Birch Borer is a problem and should be treated preventively in the spring. Leaf miner is also an issue with this species but can be treated preventively and avoided.

  Cultivars:

  Betula pendula 'Gracilis' or Cutleaf weeping birch is a more pollutant tolerant variety. Much more susceptible to Bronze Birch Borer and leaf miner. Bark does not exfoliate. Others also available.

  History and Use:

  Can be tapped to make syrup from the sap, however the sap contains about 1/3 the concentration of sugar of that of the Sugar Maple. This is only done in Alaska and on a limited scale. The fibers from the wood can be used in paper making. The bark is an excellent fuel source for burning.

• Black Locust (Robinia pseudoacacia)

  A fast growing tree maturing to 40-70’X40’ with an upright narrow and open canopy. Comfortable in a wide range of soils including salt and compacted clay this tree thrives along the Front Range and is very drought tolerant. Bland to catchy yellow in the fall and gorgeous yummy smelling flower clusters in the late spring. Short painful thorns at the base of leaves and deep dark furrowing bark appear like crusty ridges from the base to the twigs where they hardly smooth out. Propagates through legumes in pods and through an aggressive sprouting root system.

  Common Problems:

  Environmental:

  Prone to storm damage because of branch growth habits. Poor branch structure should be corrected through structural pruning every 3-5 years for the first 15-20 years of life. The seeds, bark and thorns are poisonous and should be kept from horses especially. If eaten by horses a vet check will likely be needed.

  Diseases:

  Some cankers are rare. Powdery mildew and some leaf fungi are common often yellowing the leaves mid summer and causing them to drop. Treatment is rarely warranted.

  Pests:

  The Black Locust Borer is a serious problem pest causing major mechanical wounding to the trees structural integrity on young trees and major stress on older ones. Should be controlled if tree has value.

  Cultivars:

  Several available. The most popular is the ‘Purple Lobe’ which has brilliant purple flower clusters that smell wonderful in the late spring. Again, it is very susceptible to the borer.

  History and Use:

  Traditionally used for many outdoor applications like fences, boats and nails because of its extreme hardness and resistance to rot. Also a huge favorite among honey bees who make a remarkable and sought after honey from the pollen of the Black Locust. Mistakenly named after the Mediterranean locust tree which has much religious historical significance.

• Columnar hornbeam (Carpinus betulus 'Fastigiata')

  A columnar tree 35’X15’ slow grower that prefers an unrestricted root zone. Attractive white flowers in early summer producing a “bean pod” which hangs onto the tree though the winter.

  Does well in drought and alkaline soils if root space is not confined as in parking lots and tree medians. Dark, thick, heart shaped leaf helps its ability to tolerate full sun and limited water. Is tolerant of pollution.

  Common Problems:

  Environmental:

  Restricted root zones from curb, pavement and sidewalks will cause trees to dieback. Intolerant of salt in the soil.

  Diseases:

  Trunk canker has been found on this species, however it is uncommon.

  Pests:

  Occasionally attacked by two-lined chestnut borer. Japanese beetle is known to eat significant portions of the leaves but is not currently found along the Front Range.

  Cultivars:

  Several available

  History and Use:

  Very desirable street tree for its upright form and tolerance of trimming. Has been used as a screen tree and in topiary for centuries. Pleaching is a technique employed by the hornbeam where single trunks are grown straight up and the limbs are trained to grow into adjacent hornbeams creating an elevated hedge. More common in Europe it is gaining popularity in the USA every year.

  The wood is so hard it also known as "ironwood". traditionally it was used as axe handles, wagon wheel spokes and and often as cogs for various early industrial machines like steam engines. Iron took its place in industry as its price dropped and it became readily available.

• Cottonwood (Hybrid)

• Fast growing to 75’X40’ with an elliptical or conical shape these trees like a lot of water but will tolerate medium soil moisture. A short lived (40 years) species commonly planted in yards and succumbing to Cytospora canker between 25-40 years of age. Great for a temporary screen or shade tree while longer lived trees are being established nearby.

  Common Problems:

  Environmental:

  Roots like to surface and cause significant trouble when near concrete or structures. Wounds often decay and create large cavities in the wood making them a hazard as the trees age. Structural pruning can be helpful in establishing sound branching to support the trees immense size as it matures. High risk for breaking in wind and snow loads if not thinned and reduced properly.

  Diseases:

  Trees are often afflicted with the Cytospora Canker which is a fungus that grows in the cambium of the tree slowly clogging up the vascular system causing branch dieback and eventual death. The Plains Cottonwood is significantly more resilient and resistant to this fungus than other varieties of Poplar.

  Pests:

  Aphids and Poplar Gall are the most common insect problem with this tree. Neither of which warrant suppression unless aesthetics of the tree are of major importance. Poplar borers are found but uncommon and usually a minor issue.

• Cottonwood (Lanceleaf)

• Growing to 50’X40’ with an elliptical canopy this tree is fast growing and short lived due to the Cytospora canker. This is a naturally occurring cross between sargentii and angustifolia generally found along rivers and streams in the mountains. Often suckers out from roots. Bright yellow fall foliage.

  Common Problems:

  Environmental:

  Roots like to surface and cause significant trouble when near concrete or structures. Wounds often decay and create large cavities in the wood making them a hazard as the trees age. Structural pruning can be helpful in establishing sound branching to support the trees immense size as it matures. High risk for breaking in wind and snow loads if not thinned and reduced properly.

  Diseases:

  Trees are often afflicted with the Cytospora Canker which is a fungus that grows in the cambium of the tree slowly clogging up the vascular system causing branch dieback and eventual death. The Plains Cottonwood is significantly more resilient and resistant to this fungus than other varieties of Poplar.

  Pests:

  Aphids and Poplar Gall are the most common insect problem with this tree. Neither of which warrant suppression unless aesthetics of the tree are of major importance. Poplar borers are found but uncommon and usually a minor issue.

• Narrowleaf cottonwood (Populus angustifolia)

  Maturing to 55’X40’ with a columnar shape this fast growing tree is found at higher elevations along rivers and streams. Generally a cottonless tree and easily transplanted.

  Common Problems:

  Environmental:

  Roots like to surface and cause significant trouble when near concrete or structures. Wounds often decay and create large cavities in the wood making them a hazard as the trees age. Structural pruning can be helpful in establishing sound branching to support the trees immense size as it matures. High risk for breaking in wind and snow loads if not thinned and reduced properly.

  Diseases:

  Trees are often afflicted with the Cytospora Canker which is a fungus that grows in the cambium of the tree slowly clogging up the vascular system causing branch dieback and eventual death. The Plains Cottonwood is significantly more resilient and resistant to this fungus than other varieties of Poplar.

  Pests:

  Aphids and Poplar Gall are the most common insect problem with this tree. Neither of which warrant suppression unless aesthetics of the tree are of major importance. Poplar borers are found but uncommon and usually a minor issue.

• COTTONWOOD (Plains)

• A fast growing tree reaching 80-100’X70’ it prefers very wet soil but will tolerate moderate moisture. A subspecies of Populus deltoids Eastern Cottonwood, this is one of the few deciduous trees native to the Front Range. It is an important tree historically to the area and although not a good choice for planting along streets or near structures it is an excellent choice for parks, open fields, along streams and rivers and as a property border. It has beautiful trunk and branch architecture and awesome yellow fall colors. Pleasing sound when the wind blows through the leaves thanks to the size, shape and flat design of the leaf petiole. An important habitat tree for native creatures. Lives 80-140 years.

  Common Problems:

  Environmental:

  Roots like to surface and cause significant trouble when near concrete or structures. Wounds often decay and create large cavities in the wood making them a hazard as the trees age. Structural pruning can be helpful in establishing sound branching to support the trees immense size as it matures. High risk for breaking in wind and snow loads if not thinned and reduced properly.

  Diseases:

  Trees are often afflicted with the Cytospora Canker which is a fungus that grows in the cambium of the tree slowly clogging up the vascular system causing branch dieback and eventual death. The Plains Cottonwood is significantly more resilient and resistant to this fungus than other varieties of Poplar.

  Pests:

  Aphids and Poplar Gall are the most common insect problem with this tree. Neither of which warrant suppression unless aesthetics of the tree are of major importance. Poplar borers are found but uncommon and usually a minor issue.

  Cultivars:

  Many hybrids both natural and manmade are available.

  History and Use:

  A very rich history trails this species of tree. The Native American Indians used them in ceremony as well as for shelter and fuel and for many other reasons. Currently the wood is harvested for low grade lumber and used in the manufacture of products like pallets, toothpicks and shipping crates. Wood carvers and bowl turners find it an easy medium for their tools to meander and it is gaining popularity as a furniture wood, but these are all on a small scale from local urban harvesting. Cottonwood can have a very fiery eye pleasing grain but it has to be handled very carefully during the drying process or it is unstable and unreliable to work with. Dan Odell with TC Woods in Lafayette, CO is starting to mill it into large beams to be used in timber framing.

  It rates quite low for use as firewood but if handled properly it burns okay.

  The national champion Plains Cottonwood tree is more than 300 years old, 36 feet around and 105 feet tall. It is located about a mile from Hygiene, Colorado on a closed property maintained by Boulder County Parks and Open Space. A viewing area is accessible from a short path off of Crane Hollow Rd. just North of Saint Vrain Rd. and just west of North 75th St. Call us if you want more details!

• Siberian Elm (Ulmus pumila)

  A fast growing tree maturing to 40-80’X50’ with an irregular to globe shaped canopy. Tolerates most soils and drought and prefers direct sunlight and well drained soils. Messy green flowers and winged seeds in spring and early summer. Often avoided by landscapers and city planners but is nonetheless a prolific propagator and often found along fences, roads alleys and other neglected sites where it grows into forests quickly. Will not sustain in shade.

  Common Problems:

  Environmental:

  Prone to storm damage because of weak branch growth habits. Poor branch structure should be corrected through structural pruning every 3-5 years for the first 15-20 years of life. Squirrels are avid visitors to these trees and love to make leaf and twig nests high up in their canopies. Being rodents they chew the bark in the winter for water and nutrients and to keep their teeth filed down. This can cause extensive damage to limbs and twigs and often results in major dieback of the upper canopy leaving the trees unsightly and compromised.

  Diseases:

  Wet wood is common but harmless. Dutch Elm Disease has been known to hit Siberian Elms but is a very rare occurrence.

  Pests:

  Leaf miner, aphids, Elm Leaf Beetle are common. European Elm Scale is quite routine leaving sooty mold to form on the bark and on anything under the canopy from lawns to driveways. All can be treated with a soil injected systemic insecticide called imidicloprid. Elm Bark Beetle is another common pest that can devastate a tree in a matter of months. If suspected in the tree or nearby it should be treated to avoid damage.

  Cultivars:

  Several available.

  History and Use:

  Originally widely planted by the federal government as shelter belts to help in the relief efforts of the 1930’s dustbowl on the Great American Plains. Having become an invasive nuisance it is no longer planted by city’s or landscapers. It is a great candidate for hedges as it does well when pollarded.

• Common hackberry (Celtis occidentalis)

  A medium to large tree 40-80’X50’ with a round spreading canopy growing medium to fast depending on soil and moisture. A very desirable choice for the Front Range as it tolerates high ph clay soils, drought and winds. A very tough tree if cared for early on in its life. Bares a purple fleshy fruit much sought after by birds and that unfortunately stains walks and patios. Attractive grey bark that is rough and corky with elegant structural form making it appealing for winter viewing. Yellow fall colors.

  Common Problems:

  Environmental:

  Hackberry’s tend to have very poor structure and require expert structural pruning for at least the first 15 years of life in order to prevent multiple trunks and weak branch attachments. Best planted away from structures, curbs, driveways and walks as they tend to push surface roots up and can cause damage. Easily damaged thin bark requires placement away from the potential for mechanical injury from lawn mowers, cars and weed whackers. The damage will often decay the internal wood causing extensive cavities.

  Diseases:

  Some fungi effect the leaves but chemical control is usually not warranted. Witches broom caused by powdery mildew and a mite it is very uncommon at this time along the Front Range. Mistletoe will kill a tree slowly and they are susceptible , however it is not seen along the Front Range.

  Pests:

  Hackberry Nipple Gall is so common you might think it part of the leaf structure on these trees. It is caused by a psyllid that feeds on the leaves which then form a small (1/8-1/4”) round bump on the leaf. There can be tens of thousands of these on a single tree and will remain until the leaves drop in the fall. They do not have a negative effect on the tree. It can be controlled with chemical sprays but is not recommended.

  Various scales can affect the tree but it is rare in this area.

  Cultivars:

  Many to choose from.

  History and Use:

  An excellent source for furniture grade lumber. Hackberry has the properties most suited for bending wood. It has higher tolerances than any other species. Some cultures use its leaves and berries in some foods and drinks. Some honeybees find the flowers a big resource for honey production.

  The first large scale planned neighborhood, Hyde Park, of Austin, TX in the 1880’s clear cut the old growth Live Oak forest and replanted with Hackberry’s!

• Thornless Honeylocust (Gleditsia triacanthos var. inermis)

  Maturing quickly to 50-75’X40’ with a round canopy it prefers medium soil moisture. A very common street and yard tree as it is drought tolerant and does well with pollution and compacted soils. A very hard wood. Considered a messy tree by many it is ideal for parking lot medians as it handles heat and radiant heat very well. This variety is recommended over its parent as the parent tree has abundant long and nasty thorns as well as large leathery seed pods.

  Common Problems:

  Environmental:

  Must be pruned to a single stem so as to avoid multi trunks and branch spacing needs to be established otherwise the tree will suffer breakage as it matures. (The ’Skyline’ cultivar is an exception) Surface roots are common and can be a problem if damaged from lawnmowers or root cutting for sidewalk or curb repairs.

  Diseases:

  Canker causing fungi can be a serious problem but typically only attack stressed trees. Watering and fertilizing is helpful as a preventative measure. Watering should not be frequent and light as it promotes thyronectria, (a canker fungi). Some leaf fungi are common but hardly a problem needing control.

  Pests:

  Borers can be a serious problem but typically only effect stressed trees. Honeylocust Plant Bug and Leaf Hopper are very common problems which should be treated if occurring more than 1 year in a row. Pod Midge Gall is also a semi-serious issue if persisting more than one season and should be treated. There are a variety of aphids that attack the leaves of Honeylocusts which should be controlled. Spider Mites will attack the leaves turning them golden in the heat of the summer and should be controlled. Leaf Miners are a problem but uncommon in Colorado.

  Cultivars:

  It is itself a cultivar of the thorny variety of Honeylocust. There a few other varieties available.

  History and Use:

  This tree was not a popular selection because of its numerous,needle sharp and massive thorns that defended it against casual climbing or cutting. Then, at the beginning of the 1900's, while walking among the suburban woodlands of New York City, a man discovered and propagated the natural thornless hybrid that is so widely planted today, Native Americans used the seed pulp for sweet foods. It can also be fermented for making beer. The wood is very hard and attractive. Locally it is salvaged and used in furniture. It can also be used outdoors as it is rot resistant.

• Horsechestnut (Aesculus hippocastanum)

  Similar to Ohio Buckeye but larger at 60’X45” and more conical in shape growing slow and preferring medium soil moisture. The bark exfoliates or peels. Does quite well in alkaline (high ph) soils. Doing well in cooler sites they display beautiful white flower clusters in the late spring and bare an inedible spiky fruit.

  Common Problems:

  Environmental:

  Being a weak wood the branches snap easily from snow load and high wind. Careful canopy pruning can help alleviate some this issue.

  Pests and Diseases:

  Susceptible to several fungi and pests in most climates. Seems to be free of pests and diseases along the Front Range.

  Cultivars:

  Several cultivars available including fruitless varieties.

  History and Use:

  Traditionally the fruit was used for dying linens blue and also for making acetone. The nut is poisonous, but unlikely fatal if ingested although deer have an enzyme allowing it to be eaten without harm.

  This was the tree that Anne Frank saw from her family’s attic hideaway during WWII in Amsterdam. The 150 year old tree is still there despite its many afflictions and attempts by the city to condemn it. (1/30/2009)

• Kentucky Coffeetree (Gymnocladus dioica)

  Reaching a size of 50-70’X40’ with a round to oval canopy these trees are slow growing and require light to medium soil moisture. Very attractive bark, leaves and seed pods. It is tolerant to high ph soils and drought. This is a tree that should be planted much more than it is as it is quite suitable to the Front Range and has almost no pest and disease issues. Its open canopy allows considerable sunlight through to the ground making it ideal for turf planting.

  Common Problems:

  The only issue is the litter from the seed pods which contain very hard seeds shaped like a coffee bean. It may be wise to avoid planting the tree where animals graze as it has been known to cause toxicosis in sheep, cattle, horses and humans. And given that the tree often propagates off of root shoots even a field next to a fenced in tree could present saplings attractive to grazing animals.

  More detail: http://www.library.uiuc.edu/vex/toxic/kentucky/kentucky.htm

  No known pests or diseases of any significance.

  History and Use:

  The beans have been used as a coffee substitute. (I wouldn’t do that!) The leaves and seeds can be poisonous to humans if ingested in large quantities.

  “When Kentucky was first settled by the adventurous pioneers from the Atlantic states who commenced their career in the primeval wilderness, almost without the necessaries of life, except as they produced them from the fertile soil, they fancied that they had discovered a substitute for coffee in the seeds of this tree; and accordingly the name of Coffee-tree was bestowed upon it. But when communication was established with the sea-ports, they gladly relinquished their Kentucky beverage for the more grateful flavor of the Indian berry; and no use is at present made of it in that manner.”