CO-Horts Blog

Monday, February 25, 2019

Removing a Piece of Living History

Posted by Deryn Davidson, Boulder County Extension

Trees provide so much in our landscapes from shade, to carbon sequestration, to beauty and beyond. So why would anyone remove a tree? Typically if they are dead, dying, have become a hazard for some reason or are simply in the "wrong" place, they are candidates for removal. 

Next door to where I live, we had one such tree. A huge, beautiful cottonwood that is (was) approximately 125 years old. Totally healthy and happy, but over the years had started to lean to one side and was heaving up the driveway to a mixed-used building so the owners decided it was time for the tree to go. He expressed to me that he was really torn up about the decision, but it was soon going to become a safety issue. Below are photos of the removal which necessitated a 6 person crew, two chippers, a crane, several trucks, climbing gear, protective gear and many different sized chainsaws. It's hard to believe that over the course of one day (it did take all day), 125 years of history can be removed. 


The following photos show the process:

The tree was taken down incrementally 

Some scale...the sawyer is 6' tall

The final cut

He's only 2' tall

Hauling away the wood

When you do need to have a tree removed, it's important to hire a certified arborist who has the proper training, equipment and insurance coverage for whatever size task it is. It is also important to get at least three bids on the job as they can vary wildly. The removal of this tree cost a considerable sum because of its size (in the many thousands) and the owner had one bid come in at TWICE what another bid was!! That doesn't mean that the more expensive company was trying to price gouge (although maybe), it could just be that based on the equipment they have and the labor hours it would take them makes their costs higher. You also have to factor in stump grinding, or not, and material being hauled away, or not. All of these factors will affect the overall cost of the job. 

It's never fun to have to remove a tree, but when you do, be sure to cross your i's and dot your t's when choosing who will do the work. 

Thursday, February 21, 2019

The Simple Trials of Seed Germination

Posted by: John Stolzle, Jefferson County Extension

Despite the lingering winter weather, spring is on its way. And though it may yet be just a little too early for preparing flowerbeds, raised gardens and the like, now is a great time to test the germination potential of any seeds which you may have saved in seasons past.

Seeds from leftover packets or harvested from a previous year’s crops can remain viable for many years when stored under the right conditions (CSU Factsheet on storing seeds).

If you do not have any seeds from last year, you might consider saving some this season. Seed swaps and seed saving courses are becoming popular, and carrying over seeds between years can be a fun to way to maintain continuity between multiple growing seasons. For further reading on this topic, I might point you to 'this' seed saving blog post.

Generally, vegetable seed packs sold in Colorado are required to germinate above a mandated minimum percentile, although the relative longevity of these seeds can vary. Storage conditions (for example, temperature and humidity) can affect the viability of leftovers, or seeds gathered at the end of a previous season. A quick and simple test can help to assess how your seeds are doing.

I’ve been running some seed germination experiments and would like to share the process and some results.

Overall, the methods are simple: Place 10 (or more) seeds on a damp paper towel, roll/fold up the paper towel, and check it every few days. Some additional tips and tricks are presented below.

Step 1: Seed Selection
Discard any broken, crushed, or otherwise damaged seeds.

Step 2: Preparation
To help prevent contamination, clean off a countertop or other workspace as best you can, and wash your hands. A paper towel or two can act as buffer between the “germination paper towels” and a worktop. 

Lay out two connected paper towels and then wet them with water (I used distilled water). Next, place your seeds in rows on the bottom portion of the two paper towels (image B.) - this will aid in later counting. For the most part, the more seeds you use, the more robust your results will be. In the photos, I was testing ‘ancient’ seed packets and therefore used many seeds, but 10 or so should suffice for a quick assessment.

Following seed placement, horizontally Fold Down the upper portion of the two paper towels (Image C).

Tip. 2-ply paper towels were used in these tests, they held up fairly well.

Step 3: Seed Placement & Folding
In image D., below, I made a mistake which I think is worth highlighting – I placed seeds on both the top and bottom halves of the paper towel and just starting rolling it up. Because the paper towel was not first folded (as in image C.)seeds stuck to the outer layer of the paper towel when it was unrolled - This made later counting much, much more difficult as seeds were stuck to either side of the paper towel.

After Image C., The next step is to make roughly 1.5-inch folds/rolls in the paper towel until you have something like what is seen in image E. For organizational purposes, I combined multiple germination tests (for different plants) and placed a rubber band around them (image F.). To prevent drying out, your germination test(s) should be placed in a plastic bag of some sort.

Tip: The paper towels should be damp but not dripping wet.

Step 4: Results & Analysis

By day 3 some seeds in my tests had already begun to germinate; the number of germinated seeds should be counted and recorded. 

Tip: It may be necessary to periodically rewet the paper towels.

But, as it goes, a few problems were encountered....

Image K.: Some seeds became fuzzy with fungi; this can largely be prevented through additional aseptic steps (discussed below). 

Image L.: It can also be easy to convince oneself, as I did, that seeds are germinating when actually they are not. Coriander / cilantro seeds are tricky, in my opinion; when I stared at them long enough, I began to see that they had germinated! I snapped a photo and compared it with the same seeds a few days later, and also found some un-tested coriander seeds to compare against... no germination had actually occurred.

Image N.: Unfortunately, a major blunder occurred during my eagerness to cleanup. Days after starting the test, I realized that I had tossed out the seed packet for the corn cultivar which I was testing! I highly recommend holding on to those, as well as making good reference notes!

Tip & Note to Self: It can be very helpful to keep seed labels and few reference seeds around!

Step 5: Calculation
The final step is to calculate your results! After 7 – 10 days, divide the number of germinated seeds by the total number of seeds in your trial.

In my tests, the pepper seeds did not respond very well and demonstrated a 45% total germination rate. I believe that this was most likely due to issues regarding temperature.

Temperature & Germination Time:
Knowing the difference between Warm and Cool season crops, as well as the general number of days until seed germination, can be incredibly helpful – A wonderful cheat sheet can found in Table 1 (pg. 3) of the following CSU – Colorado Master GardenerGuide.

Peppers, for example, prefer a soil temperature of 80°F and are notorious for taking a long time to germinate (an expected 10-20 days). Watermelons have similar temperature requirements to peppers but are expected to germinate somewhere between 3-12 days.

Tip: A seed propagation or heating mat can greatly improve the germination rate of seeds.

Aseptic Technique:
Implementing additional aseptic or seed disinfesting techniques can reduce the likelihood of contaminated seeds (Image K, above); if contamination is a problem or concern, the following publication from LSU Extension & AgCenter may be of interest.

Repeating a ‘trial’ or single germination test two additional times (with each test occurring on a different day) would add to the robustness of a test’s final results. This means re-doing the 7-10 day trial, three times independently and weighing your overall results... B
ut everything is a balance. Some seeds should be saved for planting in the soil!

So What? The value of knowing seed viability
Knowing the germination potential of a seed cache allows one to plan accordingly. If seeds present a 0% germination rate it may be due to a faulty test, in which case it can useful to re-test the seeds or look into temperature requirements or other confounding factors. If the seeds present a 90% germination rate, AWESOME! - One can be fairly confident that planted seeds will germinate successfully; whereas with a 0% - 50% germination rate, it may be necessary to plant seeds more densely or to check over one's seed storage conditions.

Good Luck & Happy Gardening! 

Thursday, February 14, 2019

Roses are red, violets are blue

Happy Valentine’s Day to you!  We often think of red flowers on this day, so let’s spread the love throughout the year.  Red along with yellow and orange is a warm color on the color wheel and brings excitement to the garden.  And red is a complimentary color to green, bringing balance to the green foliage in the garden.  Thirdly, red is one of the primary colors along with yellow and blue.  Picking a color theme can help harmonize the garden.  Red is a color that demands attention and causes people to focus on it.  In design, red makes a great accent and focal point.  So let’s think about red in the garden.

Of course there are lots of red flowers we can use such as roses, gaillardia, beebalm, daylilies, penstemon, salvia, iceplant and many more.  Flowers can be easy to add to the garden.  But have you thought  about plants with red foliage?  Foliage can provide a longer source of the color red then the flowers.  

So here are some red leafed plants to consider:
Shubert’s Chokecherry aka Canada Red Chokecherry-  Prunus x virginianaShrub or tree form available.  New leaves emerge green and turn red with maturity.  Try the new variety ‘Sucker Punch’ by Plant Select that provides a tree form without all the suckers at the base.  Grows up to 20’ with a similar spread.  Has racemes of white flowers in spring followed by dark berries that the birds love.  For human consumption, best is fruit is picked after a light frost and cooked to make jelly or jam.  Boiling or drying the fruit breaks down the hydrocyanic acid that is contained in the fresh berries.

Purpleleaf Sandcherry or Cistena Plum- Prunus x cistena- a medium sized shrub (6’x6’) with white to pink flowers that emerge with the foliage in spring.  Leaves are maroon red all season.  Rarely fruits.  Can acquire diseases and insects of other plums if under stress.  Makes a nice focal point in the garden.  Does best in full sun with low to moderate moisture.


Diablo Ninebark-  Physocarpus opulifolius 'Monlo' 

The color purple-red foliage named after the devil can be a cupid in the garden.  This plant obviously named after the later.  A lovely small shrub, cultivar of a native, bearing many creamy white flowers that contrast the foliage.  Prefers moist situations and part sun in Colorado.  In cooler climates, it is more drought tolerant.  Named ninebark because the bark can be peeled off in layers.  Can grow to a height of 6-8’.

Red Barberry- Berberis thunbergii cvs. ‘Fireball’-  If you want a low shrub to add color to a border and don’t mind a few thorns, this is a good choice.  Most similar cultivars grow 2-3’ in width with a 2’ height.  Deer and drought resistant and very low maintenance.

Husker’s Red  Beardtongue- Penstemon digitalis ‘Husker’s Red’- A penstemon selection with red foliage and white flowers.  The foliage is very attractive with the flowers lasting more than one month.  This plant prefers mostly full sun.  An upright grower reaching 2.5’ ht with a 1.5’ spread.  A drought tolerant plant that attracts hummingbirds and is rabbit resistant.

Windwalker Big Bluestem-Andropogon gerardii ‘Windwalker’ - A Plant Select grass with bluestems in summer turning a lovely red in fall thru a good part of winter.  This grass prefers full sun and grows 6-7’.  It is a selection of native big bluestem.  It is a very hardy grass and is resistant to deer.

For wetter areas at higher elevations, consider using Red twig dogwood, Cornus sericea that has red stems and twigs that are very evident from fall till spring when there is no foliage.  

Remember to match your plants to your landscape: Right Plant, Right Place, Right Reason.
Wishing everyone a Happy Valentine’s Day.  Be brave and put some red in your garden.
By Susan Carter, Horticulture and Natural Resource Agent, CSU Ext. Tri River Area

Tuesday, February 12, 2019

Cut Flower Challenges

Posted by: Sarah Schweig, Broomfield County Extension

Valentine’s Day is upon us. Love it, hate it, or indifferent, let’s at least appreciate the holiday as an excuse to enjoy fresh flowers! The beauty of cut flowers is ephemeral by nature, and maybe that’s part of the appeal. Still, folk remedies and DIY solutions for prolonging vase life abound. We can explore the science behind these solutions by taking a look at the most common reasons flowers don’t last at home.

Challenge: Insufficient food supply
DIY Fix: Table sugar
This idea here is simple. Plants need sugars to maintain cellular processes. Cut flowers have carbohydrates stored in leaves and stems, and these reserves will be depleted to maintain basic metabolic activity. For flowers that are harvested when fully open, like gaillardia or yarrow, insufficient food supply may lead to early senescence. For flowers that are harvested at earlier budding stages, like gladiolus or peony, insufficient food supply means those flowers may never fulfill their destiny.

Flower food is formulated to provide the ideal amount of sugar (typically glucose), as well as acidifiers (see next problem). However, because sugar is so essential to prolonged vase life and continued development, adding table sugar (sucrose) will do in a pinch.

Challenge: Microbial activity
DIY Fix: Softened water, lemon juice, aspirin, pennies
Unfortunately, plants aren’t the only sugar-lovers living in your vase water. Fresh cut flowers will lose some of those stored carbohydrates where the stems are cut, resulting in a sugary solution that encourages the growth of microbes. While supplemental sugar will support plants, it only exacerbates the microbe problem. Bacteria and fungi block flow of water and nutrients through xylem tissue, and some produce ethylene, which encourages senescence.

The vase life claims of our first DIY fixes are based on the fact that lowering the pH of your vase water will discourage microbial activity. Although hard water tends to be alkaline, chemically softened water contains sodium and should not be used in flower vases. The citric acid found in lemon juice, however, is quite effective and is a common component of commercial floral solutions. While dissolving aspirin in water does lower pH, studies are mixed on whether it has any effect on vase life. Even those studies that report a positive effect on vase life agree that floral solutions are much more effective.

Adding pennies to vase water is based on the fungicidal properties of copper. Pennies have been made from around 98% zinc since 1983, and the copper in pennies is not - and never was - water soluble. We can fully myth-bust this one (satisfying, huh?).

Challenge: Ethylene-induced senescence
DIY Fix: Vodka, gin, whiskey, etc.
Ethylene is a plant hormone involved in ripening and senescence, and thus there is generally an inverse relationship between ethylene and shelf-life. The principle here is that the ethanol, which is contained in distilled spirits, can affect the production of and response to ethylene. Ethanol has been shown to delay maturation in plants in a number of contexts. A study published in HortTechnology investigated adding distilled spirits to water to reduce tipping of paper white narcissus by reducing plant height. At certain concentrations of ethanol, plant height was successfully reduced without apparent toxicity to roots and with no effect on flower size or timing. Ethanol has also been shown to delay the ripening of tomatoes, among other fruits. While there is evidence to support this solution, at-home success would require a high level of precision. Depending on your vase size, the difference between an effective ethanol concentration and a toxic ethanol concentration could be a matter of a few drops!

What You Can Do
There are many practical and effective ways to reduce the effect of ethylene on your cut flowers without the need for laboratory precision. Place them in a spot with good air circulation, away from heat sources. Do not place flowers near your fruits and vegetables, which produce ethylene as they ripen.

Though I generally support the DIY spirit, commercial floral solutions are by far the safest bet for meeting your flowers’ basic needs. One size is not fits all for maintaining cut flowers. Roses and snapdragons, for example, need extra sugar to push blooms open. Sunflowers are highly susceptible to bacterial plugging of xylem tissue and may require a stronger biocide. While it’s tough to get a perfect solution for a mixed bouquet, you can get as close as possible by going with the pros on this one. Floral solutions are readily available and contain, at a minimum, necessary plant food and an acidifying agent to help keep xylem tissue freely conducting water and nutrients.

Another cause of reduced xylem function in cut flowers is embolism. Cut stems under warm water to help prevent these air bubbles from forming. Use clean, sharp tools to prevent crushing the stem tissue. Ensure that leaves growing below the water line, and any fallen leaves or flowers are removed, as this decaying matter will encourage microbial growth.

Eventually, even though you’ve done everything right, you’ll see signs of the battle with the microbes. When water turns cloudy or you notice fuzzy-looking growth on stems, change your vase water and re-cut stems.

How long will your Valentine’s Day flowers last? Try it out, maybe add a penny for good luck just in case, and let us know!

Monday, February 4, 2019

Does This Plant Make Me Look Fat?

Posted by: Lucinda Greene, Arapahoe County Extension

Red Twig Dogwood
I cleaned out my clothes closet over the weekend.  The articles destined for the clothing recycle non-profit fit easily into a few categories.  Some were too big (Yay!) and some were too small.  Some needed only a button sewn on or a hem mended to add them to my wardrobe. Others had outlived their usefulness with frayed collars, or torn cuffs.  And some, well, honestly…..what was I thinking?

Just like the careful attention to be paid when cleaning out closets, mid-winter in Colorado is a great time for homeowners to take stock of their landscape to assess their plants and determine what’s not working.  We have many warm days that can include an hour's time to critically assess the landscape, evaluate options, and make a plan for the upcoming garden season. What plants in your landscape are too big?  Have they outgrown their space and need pruning attention?  Large landscape shrubs like Viburnum or Red Twig Dogwood can benefit from renewal pruning in early spring. Removing dead or old stems from the center can help improve both the appearance and the health of the shrub.  Spring blooming shrubs like Lilac and Forsythia should be pruned just after bloom. Privets, Potentilla and other shrubs can benefit from a rejuvenation pruning every few years.  For more information on pruning, click here. 

Russian Sage
What plants aren’t performing in their space?  For example, some cultivars of Russian Sage take over bed spaces with rhizomatous growth.  Do other plants look a little unkempt or have they exceeded their bounds?  Digging up these shrubs and doing a good root pruning, or dividing these shrubs in spring can help keep them in check.  Have some shrubs outlived their usefulness, or become too woody?  Repeated shearing of shrubs can create unhealthy plants.  Have other shrubs become unattractive due to winter feeding by wildlife?  Many ground cover junipers suffer from vole damage in Colorado.  Carefully pruning out the dead limbs can improve the overall appearance of these foundation shrubs

And, honestly, are there some plants in your landscape that you have struggled with ever since they have been planted?  Do you battle with these plants regularly? Perhaps you fell in love with the blooming azalea that was calling to you at the nursery a few years ago, but you can’t get the same glory in your landscape due to our alkaline soils? Do you have sun-loving plants that no longer bloom because they have become overshadowed by the growth of shade trees?  Or perhaps you have broadleaf evergreens like Boxwood or Euonymus that suffer significant winter desiccation every year, or are not performing because they are sited on a southern or southwestern exposure? 

As you do this evaluation, take a good hard look at what is pleasing to you in your landscape, and develop a plan to tackle some of the maintenance issues, (those hems and buttons) and perhaps consider dividing and transplanting plants (recycling) or removing some plants altogether to make way for new appropriate species (shopping is always fun).  Perhaps a friend or neighbor would appreciate your plant recycling efforts. 

A number of native plants and cultivars of native plants are making their way into retail nurseries.  These plants are ideally suited for the high, dry Colorado climate and our alkaline soils. When sited correctly, they help reduce water use and landscape maintenance. (Good-looking plants, and I don't have to work hard?  Sign me up!)   Look for shrubs that survive in alkaline soils, have light requirements suited to the proposed space, and are suitable for your zone.  Ninebark, Apache Plume, and Snowberry are good examples of native shrubs that add beauty to the landscape. If you would like to learn more about Native shrubs please click here. 

Cleaning the plant landscape, just like cleaning a clothes closet can give you a whole new feeling of accomplishment.  By making a plan now to care for the health of your existing landscape, and incorporating plants appropriate to your area, you can increase your enjoyment of your outdoor space, and make better use of your precious time and water resources.  Everything fits.  And, I must say, it looks really good on you!