The Science Behind Your Christmas Tree by Elaine Lockey

photo courtesy of SeattleTimes.nwsource.com

Going to pick out a Christmas tree is always an exciting holiday tradition.  It’s one my family never really took to though.  My father preferred the variety of tree that didn’t drop needles or require watering.  Once I had a home of my own, I decided that I wanted a “real” tree from then on – I sought the fresh smells and natural beauty that an artificial tree just can’t provide. 

As I perused the tree lots looking for the right tree, I have to admit, it never crossed my mind to think about why the choices are Douglas Fir, White Fir and Scotch Pine for the most part. What makes them the tree of choice to adorn my living room?  And once I brought the tree home, what can I do to keep it greener longer?

It turns out, there is an incredible amount of research behind the selection of trees specific for growing as a Christmas tree, and another whole body of research into how trees can behave more to our liking when growing in a tree stand - way more than the time that it takes me to pick out the perfect tree.  Just who is doing the research?  One such place of research is the Christmas Tree Research Center at the Nova Scotia Agricultural College.  

Focusing on the Balsam Fir, one of the main trees grown for Christmas trees in Canada, the Center has focused much of their study on how to keep needles greener longer.  This goes well beyond just remembering to put water in the tree stand.  The bonuses of this research are many, from the longer duration of freshness of trees in tree lots to how long they can look good in your house.

Needle drop is triggered by the hormone ethylene.  Ethylene is the same hormone that is released when an apple ripens. With some manipulation of the hormone, the Center has been able to find some possible solutions to slow down needle drop by half so a tree has a much longer life span. Two different solutions, one taken in through the trunk in liquid and the other in a gas “bath” affect the synthesis of the hormone and also the needle abscission layers from forming.

Other research from the Center has found that white LED lights provide the most benefit over other color spectrums, no lights, or regular incandescent or florescent lights.  Needle retention in white LED light was much higher. Blue performed the worst.  Additionally, there is more benefit to the tree if you leave the lights on all the time instead of turning them off at night.  Consequences to your electrical bill aside, if you want to keep needles on your tree longer, trees do better in the constant light.  When they are in the dark, respiration increases and they use up a lot of calories that they aren’t taking in.  

Christmas trees and greenery are more than a billion $ industry around the world. There are more than 30 million live Christmas trees sold just in the US every year.  Countries like Canada, are spending more to help the industry find solutions and eventually hope to create the perfect Christmas tree, or at least a much improved one.  New Mexico State University’s Christmas Tree Research Program has done extensive work on tracking the provenances of many commonly used trees and has introduced a tree to the industry that does better in the climate of the SW.  Some other institutions, such as Oregon State University’s College of Forestry research genetics, fertilization and disease management.  

Picking out the right Christmas tree for your home can be a science in itself for you and your family.  No matter how you go about doing your research and making a selection, it is fun to know some of the institutional science that has gone on behind the scenes to keep this long-standing tradition going. Oh, and keeping ripening fruit away from your Christmas tree is recommended.  Who knew?

Tip: Charlie Brown Christmas trees can solve that search for perfection.  There is no bad-facing side to one of these trees because they are all irregular. You can get away with just hanging one ornament and no lights.  In Charlie Brown’s world you don’t even need a tree stand, just some planks of wood! 

Help For Storm Damaged Trees by Carol King

CSU Extension

Many Front Range residents awoke on Wednesday to find that their trees had been further damaged by Colorado's second major fall snowstorm of 2011. It seems that we are not catching a break this year!  Perhaps you are wondering just what to do about it.

The Colorado State Forest Service offers these first aid tips for dealing with damage.

Read about it here.

Mountain Pine Beetle Spreads to Front Range

Photo Courtesy of University of Wyoming

The Denver Post reports that the mountain pine beetle has spread to Colorado's Front Range cities, but forestry experts and city arborists do not expect losses on the scale seen in Rocky Mountain forests.

Read the whole story here!

What Does Grow Under Pine Trees? By Nancy Szilagyi

Everyone has seen those bare spots under pine trees.  Do you wonder why?  Perhaps you have heard that nothing likes to grow in such acidic soil.  The needles are thick under these trees. They must just make the soil too acidic for anything to want to live there. That’s what I thought.

Recently, I took an on-line class given by Dr. Tony Koski, professor at CSU and Extension Turfgrass Specialist.  I learned that our soil here in Colorado is very high pH--free lime.  Although pine needles fall in abundance, there could never be enough pine needles to lower the pH. Fallen needles may SLOWLY make the soil more acidic, but more likely for the better since it neutralizes the lime. It takes decades to change pH and will not decrease by more than .5 units. There goes that myth!

Following are the some of the real reasons many things, especially turf, don’t want to grow under these trees:

The turf tends to be smothered by a thick mat of pine needles.

Dense, year round growth leaves little light.  The only thing that will get through is ‘left over light’, according to Dr. Koski.  This light lacks     intensity and quality. This ‘left over light’ is what the tree does not use     for photosynthesis.

Any other plant will struggle with below ground competition—tree roots     competing for water and nutrients.  Our tree roots here in     Colorado tend to be fairly shallow.

Evergreens, with their dense growth, shed rain to the outside of the tree     line, so it’s dry under the tree. Without adequate water and nutrients,     most plants will suffer in this setting.

But, what does grow under pine trees?

 I have found a few things that for whatever reason, seem to work well under them.  The first is Brunnera macrophylla.  It has a couple of common names; False-forget-me-not, Siberian Bugloss and Heartleaf Brunnera. This one, my favorite, is ‘Jack Frost’.  It doesn’t mind the dense shade.  It doesn’t seem to mind the thick layer of pine needles around it, and the lacy blue flowers are dainty and beautiful.  After flowering is over, the stems can be cut back all of the way and you are left with the lovely heart shaped leaves for the rest of the season.

  The second, which I have come to count on, is Ceratostigma plumbaginoides, common name, Blue Leadwort. It, too, has dainty, pretty blue flowers, but it blooms later in the season than Brunnera. The flowers are followed by seed pods that look like little red tufts and are quite attractive.  The foliage is semi-evergreen and turns red in the fall. This plant is able to tolerate full sun to full shade!

  The third is Kinnikinnick.  This is a native plant in Colorado.  You’ll find it in the mountains growing quite happily along with all of the evergreens around it.  Kinnikinnick is more of a ground cover with evergreen, glossy, rounded, small leaves.  It blooms with tiny white and pink bells and shows off with pretty red berries in the fall.

All three of these plants will need additional irrigation, however, since lawn sprinklers and rain can’t reach them well, but it’s worth the extra time.

So, at least we know there are choices.  The easiest one would be to allow a natural mulch of needles to occupy that space, and that is just fine.  In fact, I find pine needle mulch quite attractive!  The other choice is to try one or more of the above plants, especially if you must have flowers in as many places as possible!

My Poor Beloved Currant Bush by Nancy Szilagyi

I love my Black Currant bush (Ribes odoratum ‘Crandall’)!  I have had it for eight years, and I have reaped several abundant harvests.  I have sat under it on a hot day and picked off currants until my hands were purple.  I have made currant scones and given them away to many friends and fellow gardeners.  I have made three batches of Currant Liqueur (Crème de Cassis) which have all been wonderful, even heavenly!  These have also made popular, sought-after Christmas gifts, although it is hard to share very much. 

In spring I wait for it to leaf out. I wait for it to bloom with its lovely, yellow, clove-scented blossoms.  I watch the blossoms wither, and wait for the berries to form.  I have seen branches so heavy with clusters of the shiny black fruit that they are bent almost to the ground. 


It has yielded an average of 8 pounds of fruit each year after the first two summers.  I’ve been so pleased with the harvest, that I have recommended it to many people.

This year I watched it leaf out and I watched it bloom.  But, alas!  Soon, I watched some of the branches’ foliage pale in color (chlorosis) and crinkle inward (leaf curl).  What could be happening! In the rush of spring garden clean up and planting, and the frequently rainy weather this year, it was a few days before I got out there to inspect it.  I took out my magnifying glass, and, sure enough, currant aphids (Crytomyzus ribis)!  NOOO!

The next day that it wasn’t raining, I broke out the insecticidal soap.  I tenderly held each branch so that I could spray each cluster of leaves from all sides and directly into the cluster. My hands were covered with soap.  So was the spray bottle.  They were so slippery that I had to go in and rinse both several times before I was done.  My hands were so tired I had to keep switching from left to right. It felt like an acute case of tendonitis!  But, I was not going to let those aphids have my currant bush!

A couple of days have passed, and fortunately we did not have rain during that time to wash off the soap right away.  I have once again inspected the clusters of leaves.  I do not see any aphids that are moving.  I will not be lulled into a false sense of security, however.  The bush will have to undergo diligent and frequent inspections for a while, and probably more applications of insecticidal soap. 
I have high hopes of my beloved bush yielding its usual glorious harvest this fall.  I can already taste the scones.  Maybe even with a small glass of liqueur!

Cheers!

 

 

Pest Problems Abound After a Dry Fall and Winter by Mary Small

We’ve sure had a dry fall, winter and early spring! And alas, as I write this, I can hear the wind roaring outside.  Our persistent dry, warm, windy weather has stressed plants and this will make them susceptible to disease and insect pests in 2011. Many tree care specialists think there will be a lot of damage this year.

Here are a few problems we can expect to see:

CSU Extension

Winter burn on evergreens.  In fact, you can see it now. Look for brown needles, particularly on the south or on the windward side of the plant. Needles will be uniformly brown from the tips inward.  It’s the result of our dry, warm, windy weather that promotes transpiration, water loss through the needles. This isn’t a problem until there’s not enough water in the soil to replace what gets lost. Sometimes, though, water loss happens so fast (like on windy days!) that plants  cannot keep up with it. Needles lose so much water so fast, they dehydrate or “burn”. 
Little can be done at this point, except to water plants and hope for rain or snow! This spring’s new growth will mask most of the brown needles which will eventually fall off. Winter burn does not usually kill established plants, but may seriously damage younger ones.

University of Minnesota Extension

 Cytospora canker.  A common fungal disease found on many trees and shrubs.  While the problem is a common one, we will probably see more because of weather stresses.  This pathogen is a weak one and only successfully damages plants stressed from something else, like drought. Look for dead or poorly leafing branches this spring and examine them more closely for sunken, discolored lesions.  These are the cankers. Prune damaged branches off below them. Water trees every 2-4 weeks if there’s no significant snow melt or rainfall.  For more information on Cytospora canker management strategies, see fact sheet 2.937, Cytospora Canker at http://www.ext.colostate.edu/pubs/garden/02937.html  

Barkbeetles.org

Borers and bark beetles that attack stressed plants.  When trees are stressed, they produce chemicals that can attract certain insect pests. An example of this is the spruce ips beetle. Spruce ips beetles feed in the conductive tissue under the bark, causing needle and branch death. They are typically found in the upper portion of mature trees. They also damage recent transplants.  Actively growing, healthy trees are more resistant to insect pests.  Promote  plant health by watering during dry periods, but avoid over-irrigation as that  stresses trees, too.  Insecticide treatments may be applied to trunks just prior to the time when adults fly and begin laying eggs in the spring.  For more information on ips beetles see: http://www.ext.colostate.edu/pubs/insect/05558.html

The Catkins Cometh! by Carol King

I  know that spring has “sprung” when the street in front of my house becomes covered with cottonwood catkins. Our neighborhood in North Lakewood has many cottonwoods, poplar, willows, birches and aspen trees: all catkin-loaded!  And spring is definitely here.

The catkin is is a strand of tiny unisexual flowers, blooming on many species of trees. The flowers are tiny and inconspicuous, but the blooming catkins are lovely, though very short-lived.  Catkins rely on wind to spread their pollen, and we have certainly had the wind helping out. After the female flowers are fertilized, the male catkins wither and drop.

Each species of tree has its own habits and forms, which are interesting to contemplate. The brief beauty of the catkin-bearing trees hearlds early spring, a welcome sign of greenery to come!

The word catkin is derived from the Dutch katje, meaning "kitten", because it resembles a kitten’s tail. Enjoy this brief display which hints of Springtime!

Force Blooming Spring-blooming Trees and Shrubs

Buds will be swelling soon on our spring-blooming shrubs. It is always fun to rush the season and bring some inside to force bloom. Here's a great article from Horticulture Magazine

on the best way to do just that!

Christmas Tree Recycling by Donna Duffy

That lovely, fragrant cut tree you bought weeks ago has probably seen better days by now. It’s time to get it out of the house! Following are some options for recycling the tree once you’ve removed all of the decorations and tinsel. One caution: don’t burn the tree in your fireplace – the pitch content in the bark and needles can cause them to burst into flames from the intense heat.

Treat the birds!

Take that dry tree outside! You can prop it up against the house or leave the tree stand in place. Decorate it with popcorn, fresh cranberries, peanuts in the shell, pine cones with suet and birdseed; apples, rice cakes, or dried corn bundles. The birds will love the variety of treats – as will the squirrels. Use natural string, ribbon and raffia for hanging the edible decorations. The birds will use this material for nesting in the spring.

Use the Tree Boughs for Mulch

Recycle the boughs and use them as mulch in your own yard. Just cut the boughs off the trunk or larger branches and place them on your perennial beds. The boughs will protect dormant plants from drying out as fast as if they were fully exposed. They'll also keep the plants dormant longer because the soil temperature won't rise as quickly on sunny winter days. Be sure to remove the boughs as the plants start to emerge from dormancy. Then chop boughs into small pieces and add them to your compost pile to provide some acidity.

Recycle Your Whole Tree

Jefferson County has several sites where Christmas trees can be dropped off. This website will be helpful to find the location nearest to you: http://www.recycleyourchristmastree.com/counties/jefferson.html.  Before you take your tree, find out if there are restrictions. Many sites will not accept flocked trees and all sites require thorough removal of decorations to protect both man and machine in the recycling process. The best rule of thumb is to take your tree to the recycler in the same condition that you would find it in the forest. Then go back and pick-up some mulch for your garden! Pine needles are great for protecting fall planted materials, and bark chips are perfect for informal walkways.

City of Golden Tree Recycling

The City of Golden will be accepting holiday trees for recycling beginning Sunday, Dec. 26 through Sunday, Jan. 23. Trees may be dropped off at any time between these dates at the Golden Recycle site, just west of Hwy 93 and north of Golden Gate Canyon Road. Please leave holiday trees at the south end of the site where a sign announcing the recycling will be visible.

Trees must be stripped of all ornaments, hardware, strings of lights and tinsel. Mulch from the chipping process will be available for free at the public pickup site on 11th Street, just west of the Clear Creek History Park. For further information please contact the City of Golden Forestry office at 303-384-8141.

Rooney Road Recycling Center

Tree recycling is available to residents of Arvada, Edgewater, Golden, Lakeside, Morrison, Mountain View, Wheat Ridge and unincorporated Jefferson County. The Center is located at 151 South Rooney Road. Winter hours are: Wednesday, Friday and Sunday, 10:00 am – 3:00 pm. On Saturdays, the Center is open from 8:00am till 4:00 pm. There is a charge of $1 for single trees. For more information, call 303-316-6262.

Fall and Winter Watering by Donna Duffy

We are on track for one of the warmer autumns on record. In addition, we know that Colorado winters can have long spells of dry, warm and windy weather. During the cold weather seasons, pay special attention to weather and soil conditions and provide supplemental water to keep the root systems of trees, shrubs, lawns and perennials alive and healthy. Here are some tips to help them survive the winter.

General Tips

Apply water in mid-day when the air and soil temperatures are above 40°F and there is no snow cover. If the root systems don’t receive adequate water, the plants could appear normal in the spring, but may be weakened and die off in the summer when temperatures rise. Lack of winter water may also create insect and disease problems. Whenever you water, remember to disconnect the hose when you are finished!

Trees

Newly planted trees are most susceptible to winter drought injury. All trees utilize water most effectively when it is allowed to soak into the soil to a depth of 12”. Whether you use a sprinkler, deep root watering device or soaker hose, be sure to apply water to many different locations below the tree and beyond the canopy of branches. Trees need 10 gallons of water for every inch of trunk diameter (measured at knee height). If you use a deep root needle, insert it only 6-8” below the ground – if it’s deeper than that, it’s out of reach of the tree roots.

Shrubs

Even established shrubs will benefit from winter watering in dry years. Apply five gallons of water for small shrubs (less than 3’) and 18 gallons for larger shrubs. If the shrubs are newly planted, water twice monthly. Mulching the shrubs will help them retain moisture.

Roses and Other Perennials

If you planted perennials in the fall, they probably didn’t have much time to establish a strong root system and they will need winter water. Water when the ground appears dry by checking the soil condition 2-3” deep.  All perennials that are in a windy or southwest location will benefit from supplemental water. Keep an eye on the mulch around your perennials, it’s often blown around in the winter and will need to be put back in place or supplemented.

Lawns

Lawns can suffer winter damage as well as trees, shrubs and perennials, especially newly established lawns. These new lawns will need supplemental winter irrigation following the general tips above. During dry winters, lawns are more susceptible to winter grass mites and dessication if occasional winter irrigation is not applied.

For More Information…download the CSU Extension Fact Sheet #7.211 “Fall and Winter Watering."

Needle Drop in Evergreens by Mary Small

Spruce trees are getting a lot of attention this fall. Their inner needles are turning yellow or brown and dropping off. 

To put your mind at ease, it’s not unusual for these conifers to shed interior needles beginning in late summer and continuing well into fall.  This is normal evergreen behavior.

In fact, all conifers (“evergreens”) including spruce, pine, fir, juniper and arborvitae lose their oldest needles every year. Contrary to what the name implies, “evergreens” are not really green forever. Their needles generally have a 2–4 year life span, although spruce trees live about 5-7 years. 


While needle loss occurs every year, the process is usually gradual, over a period of several weeks or even months, depending on species and weather. It’s so gradual, that you might not even notice the needle drop.

Some species can shed needles in a fairly short period of time, making it look as though they’re in serious trouble. And environmental problems, like drought, can make needle drop happen more quickly than it would if the tree was healthier. 

That’s what’s wrong with the spruce this year.  August and September were low moisture months, with most Denver metro locations receiving only a trace of precipitation after early August.  These dry conditions stressed conifers, particularly spruce, which prefer moister conditions than we experienced.

There is no need to treat evergreens for the condition.  This fall and winter, ensure all evergreens are irrigated monthly in the absence of rain or snowmelt. Apply water so it reaches the absorbing roots.  For established plants, these are located a distance of two to three times the height of the plant away from it. For newly planted trees, apply water to the planting hole and just outside it. Always irrigate when the soil is unfrozen and able to absorb the water. 

Studies show that fall-applied water has great benefit.  Roots are still active and can absorb water as long as soil temperatures stay above 40 degrees Fahrenheit. 

If evergreen needle drop is occurring on outer needles or both inner and outer needles, a closer look is needed.  Branch samples may be brought to the Jefferson County Extension Plant Diagnostic Clinic, located on the Jefferson County Fairgrounds, for diagnosis.  Jefferson County residents will be charged a $7 fee, non-Jefferson county, $10.

Cotoneaster Gives Color Through the Fall by Heirloom Fan

When we moved into our home, we found a low growing woody shrub in the back yard that provided color and interest for several seasons. If you have not tried a Cotoneaster in your landscape, you might want to consider it.

Cotoneaster is from the Rosaceae family, which includes apples, peaches, plums, crabapples and 250 other common landscape plants. There are several varieties of Cotoneaster, including those that are deciduous and evergreen types. Some of these are even used in bonsai applications.

The Cotoneaster in our landscape is the deciduous variety, with shiny small green leaves, woody stems and small white/pink flowers in the spring. But one nice feature that I appreciate is as color begins to fade in the fall garden, the Cotoneaster comes forward with vivid bright red berries. As the leaves drop off the berries are even more of a standout against the dark woody stems. The berries are similar to rosehip shape and the ones on my bushes are very shiny and look great against snow as well. They are also attractive to birds for winter feeding. Cut a few stems around Christmas to add a holly like touch to arrangements, too.

So if you are looking for ways to extended color and interest in your garden or landscape, you might want to try a Cotoneaster plant.

Big City Trees Discourage Crime!

Yet another reason to plant trees!

Along with energy conservation and storm-water reduction, scientists may
soon be adding crime-fighting to the list of benefits that urban trees
provide.

Read the whole story here!

Appreciating Pyracantha by Elaine Lockey

Firethorn, Pyracantha coccinea, is one of our showiest fall shrubs.  The first time I saw one I did one of those drive-by double takes, turning my car around so I could get a closer look.  Then I said to myself, “I have to have this plant.”

Ask gardeners who have Firethorn in their gardens and you’ll get a wide range of opinions as to its usefulness.  The biggest complaint has to do with it’s ½ - ¾” long thorns, hence the common name Firethorn.  This is a plant that you want to put in a place where it can grow to its full potential without much pruning.  Depending on the cultivar, it can range from 3’-10’+ ft height and spread. It is not advised to shear it and pruning should only be done occasionally to maintain its natural beautiful shape.  Believe me, the less you have to prune this the more your arms will thank you. The one exception to this is that Firethorn makes a beautiful espalier! Due to its thorns you would want to avoid putting it right next to sidewalks or other traffic areas unless you want to keep people and animals out of a certain area. Great to keep those pesky neighbor kids from short-cutting across your garden!

This is truly a four-season plant. It offers showy white flowers in the spring, evergreen lustrous green leaves, and its best known feature- orange or scarlet berries, actually berry-like pomes, fall into winter. It generally has an upright open shape but can be highly irregular and arching. Birds love eating the berries and it offers great cover for birds from predators. Plant this by a window to see all the bird visitors up close. It is considered deer resistant, always an added benefit.  The berries also make excellent jelly! (see recipe below) I would recommend either planting Firethorn as a specimen plant or using it as an attractive thicket-like mass planting.

Firethorn is hard to transplant so plant it where you will not want to move it in the future.  It grows better in full sun, however, the leaves can sometimes burn in the full winter sun so a sunny sheltered location would be best. It is best to plant this in the spring as it is slower to establish.  It can be susceptible to fire blight but that is not as commonly found here with this shrub as in other states. Some cultivars are not as winter hardy as others.  A great Xeriscape plant, it does not need much water, ¼- ½ ” of water a month and can withstand dry and droughty conditions once established.

Belonging to the Rose family Rosaceae, Pyracantha coccinea’s native habitat is Italy to Caucasus.

The following cultivars are recommended as best for Colorado to zone 5. They are either selections of Pyracantha coccinea or P. angustifolia:
‘Wyatti’: heavy fruit producer, orange-red fruits
 ‘Gnome’: hardy, medium size, compact form, orange fruits
 ‘Kasan’: very hardy, spreading habit, orange-red fruits
 ‘Lalandei’: vigorous growth, grows to 10’+, hardy and reliable, orange-red fruits
 ‘Pauciflora’: finer textured foliage, lighter fruit producer, 4’ ht and spread, orange fruits
 ‘Monon’ and ‘Yukon Belle’: medium size, quite hardy, orange fruits
These different cultivars offer different overall sizes and compactness, fruit colors or heavier fruit production than others.
Plant and enjoy this spectacular and easy to grow shrub, but with one last tip - wear leather gloves and long sleeves when planting this!

Pyracantha Jelly
Place 7 cups washed pyracantha berries in a very large pan with 5 cups of water.
Simmer uncovered for 20 minutes. Strain through a cloth.
Measure 3 cups berry juice, ½ cup lemon juice and 7 cups sugar into a very large pan. Over high heat, bring to a boil, stirring constantly.
Immediately stir in one bottle liquid pectin, bring to a full rolling boil and boil hard for one minute, stirring constantly.
Remove from heat, skim off foam, and pour into sterilized glasses. Follow recommended canning procedures for your altitude.
 (recipe courtesy of Texas Cooperative Extension Service)

Fire Blight Arrives in Our Trees! by Mary Small

As if trees didn’t have enough trouble from last summers’s hail, October’s damaging freeze and a late spring, some have now developed fire blight!  This bacterial disease is common on crab apple, apple, mountain ash and pear. 

Warmer than average temperatures during blossom time creates ideal conditions for disease development. If rain falls at the same time, its spread is rapid.  And guess what?  This spring was just perfect, if you were fire blight bacteria!

Fire blight symptoms can be found as early as petal drop, when infected blossoms shrivel and turn brown.  During the late spring and summer, infected branches wilt and darken as the bacteria colonize them.  Branch tips darken and bend over in a “shepherd’s crook” formation, appearing as though they were torched.  In wet weather, it’s easy to find small blobs of cream colored bacterial ooze on infected tissues.  Branches and trunks also develop cankers, areas of sunken discolored tissue.  

Fire blight bacteria spend the winter in the canker margins until warm, moist spring weather stimulates bacterial growth and oozing.  Insects carry the ooze to flowers where the bacteria reproduce quickly in the sugary nectar.

Bacteria also spread through splashing water into natural openings and wounds created by hail, insect feeding and pruning.  We’ve seen a great deal of fire blight this year on crabapples damaged by last July’s severe hail storm.

Prune out the damaged branches.  Make pruning cuts 8 to 12 inches below visible signs of infection.  Surface sterilize pruning tools with bleach, ethyl alcohol or disinfectant sprays after each cut to avoid spreading fire blight on pruning tools. 

Local weather conditions determine disease severity each year.

Check out this CSU Extension fact sheet for more information.

Trees Not Leafing? Here's Why by Mary Small and Robert Cox

    Many Front Range trees and shrubs are not leafing well, leafing slowly or appear to be dead.  A number of these were injured by the severe cold snap last October 8-9, 2009. The damaged plants had not fully “hardened off” when temperatures took their sudden drop.  (Hardening off is a natural, gradual process that prepares woody plants to survive cold winter temperatures.) 

In some cases, affected plants were already stressed by environmental conditions and predisposed to further damage from the cold. Numerous ash were already struggling with “ash decline” or borers.  Some catalpas had verticillium wilt, a fungal disease that attacks conductive tissue and weakens plants.
 Trees and shrubs that received late summer or early fall irrigation and nitrogen fertilizer remained succulent rather than hardening off and were more prone to cold injury. 

 A significant amount of dieback has been observed on rose, spirea, blue mist spirea, honeylocust, crabapple, ash, Amur maple, red oak, catalpa, hackberry and others.  Some trees with dead tops are just now pushing shoot growth from latent buds in the trunk. Any trees showing this type of growth will generally not develop into strong landscape trees and should probably be removed. 



For more information, call the Jefferson County, CSU Extension at 303-271-6620.

Cottonwood Cotton by Carol King

I saw the first whisps a couple of days ago. Soon we will be sweeping up big piles of the stuff. As it warms up, it will be sticking to our sweaty bodies; we will be spitting it out and wondering when will it all end. What you say? Well, cottonwood cotton of course!! Planttalk Colorado provided this information about cottonwood cotton.

"Cottonwood trees are dioecious, meaning they have male and female flowers on separate trees. Cotton shed by female trees in June is often so abundant that it turns nearby lawns white. Heavy snows in winter promote plentiful new growth. This in turn fuels abundant flowering of both male ("cotton less") and female (cotton-bearing) cottonwoods in the spring. Flowers on female trees, after being pollinated by wind-borne pollen from male trees in April, develop small green capsules that split open in June to shed small seeds carried by wind-borne "cotton".



It takes cottonwood seedlings several years of growth to become sexually mature and flower. This explains the observation for a female tree that "it never had cotton for years after the seedling came up. Now it has cotton every year".

Some municipalities have ordinances against female cottonwood trees, as the wind-blown cotton is deemed a nuisance. A few municipalities enact ordinances against male ("cotton less") cottonwoods, because the April pollen causes problems for allergy sufferers. Although cotton can be a nuisance, it has no allergenic properties. People with allergy symptoms during June cotton distribution are probably suffering from other wind-borne pollen - from grasses, weeds or other trees.

A few cases of nursery-sold "cotton less" cottonwoods later developing cotton are usually due to mislabeling or to a misunderstanding. Some hybrid cottonwoods sold in the nursery trade are listed as "sterile female hybrids". These are not "cottonless" because they are not male. "Sterile" in this case refers to the fact that they bear inviable seed, incapable of germinating but still produce much cotton to distribute that inviable seed.

Ethephon, sold as FlorelT, is labeled to prevent cotton development in female trees and needs to be applied during flower development."

So there you have it, dear gardener. It's all about making more cottonwoods!

Welcoming the Peach Blossoms by Heirloom Fan

After the devastating hailstorm which hit in the middle of the summer last year, I wondered how the trees, bushes and perennials would handle that type of trauma and still survive. After the storm, like many people, we found our trees had sustained damaged such as snapped branches and even part of the bark “skinned” on the branches and limbs. I wondered not only what this would mean to the health of the tree last year but what would happen after it went through the winter dormancy and if we would see a good recovery in the spring.


Luckily today, I saw one of the first glimpses of how nature can recover after an event like this as I see my peach tree slowly begin to open its flower buds. Even better, there were several bees that were making their way to the open blossoms. These small, dark, shiny bees were most like orchard mason bees, which are extremely beneficial for fruit production and are non aggressive.

As I began checking the tree a few weeks ago, I also noted that most all of the limbs and braches did have leaf and flower buds, including those that had sustained damage. I purposely did not do pruning on my peach tree this spring just to see how many of the branches would show recovery and so far, I can say that it looks very promising. I found that even some limbs that had damage in spots, still seemed to “work around” that damage and produce the leaves and blossoms in the non injured areas.

There are also other bushes and trees that are not yet ready, such as the lilac so the progress and recovery of each of these will be closely watched. Last year, after the hailstorm, a very odd occurrence happened where trees and bushes re-bloomed midsummer. To see a lilac in full bloom the first week of August was strange indeed and showed the extent of the trauma that these plants endured.

I am hoping for the best and will be reporting on what I see as we go along this spring.

Bushwhacking! Proper Shrub Pruning by M J Lechner

Early spring is a good time to sharpen those pruners and get busy thinning and shaping the shrubs and bushes on your property. 

The first thing to consider is whether or not  blooms form on old branches or on new wood.  Forsythia, lilacs and hydrangea all bloom on last year’s growth, so they should be left alone until after they flower.  Hibiscus, many clematis and buddleias (butterfly bushes) bloom on fresh growth, so they can be thinned and shaped before the bloom season. 

There are two ways to approach pruning your shrubs: one is to thin and the other is to regenerate the entire plant.  Thinning is the less drastic approach.
Remove all the dead, diseased and weak (thin-diameter) branches.
Remove all the crossing, rubbing branches and those that lay on the ground.
Remove some of the larger stems (10-50%) from the older branches.
Selectively shorten and thin the remaining stems.
Remove some of the new sucker growth

Regenerative pruning is not for the faint of heart.  It literally means cutting your shrub all the way to the ground and letting it regenerate.  This is best done when a shrub has really gotten out of hand.  Before doing so, consider the following:
Is the shrub healthy and vigorous?
Is this a shrub that will produce abundant new stems?  (Old lilacs that are non-producers or tend to develop powdery mildew are perfect candidates!).
Is this a grafted shrub?  If so, be careful not to cut below the graft.

This is not always the easiest of garden chores, but doing before the heat of summer and the extra weight of  leaves makes it a whole lot easier. Get busy!

Time to Limb up for Spring! Proper Tree Pruning by M J Lechner

Early spring, before bud burst, is the perfect time to assess any small trees on your property.  A couple of things to think about as you walk around your yard:
Are your pruners in shape?  If not, its time to either invest in a good set of by-pass pruners or head to your nearest gardening center to have them sharpened. By pass pruners give you the clean cut you need when pruning. 
Do you spot any co-dominate trunks?  Now is the time to choose your leader and either remove or shorten the other branches vying for the top spot.  As hard as it is to pick, it will save you a lot of heartache in the future- especially when we have heavy wet spring storms!   Most limb failure in Colorado comes from unattended co-dominant  branches….

Are your small trees becoming exceedingly ‘decurrant’ or bushy?  We all want lovely rounded trees, but not too soon.  Delay the development of a decurrant form by maintaining the leader and selecting a few strong permanent branches higher up in the tree.
Are your branches ‘in the zone’?  For small trees, such as a Chanticlear Pear, you will want your canopy to be at least 5 feet up.  You can elevate the canopy by gradually removing the lower branches.
How’s your ratio? A good rule of thumb for any tree is to attempt to maintain a 60/40 ratio of crown to trunk.  That means the trunk should be a bout 40% of the total height with the crown comprising 60%.
Take advantage of this gorgeous weather to give your small trees ‘the once over’.  They will thank you by living longer, healthier lives in your gardens.