CO-Horts Blog

Wednesday, February 26, 2014

Sixty Second Secrets for Gardening Success: Butterfly Gardening

Today on Sixty-Second Secrets for Gardening Success: Butterfly Gardening.

A successful butterfly garden will have several key features which create a suitable habitat for butterflies and their larva called caterpillars. The first thing to remember is to avoid using insecticides in your garden.

Next be sure your garden has the proper water. Create areas where water can puddle then add rocks in the sun so butterflies can sun and warm themselves. Last, add plants which will provide shelter and food throughout the entire season. Butterflies tend to be attracted to brightly colored fragrant flowers. Plants to consider growing for a butterfly garden in Colorado include bee balm, butterfly bush, dill, lilac, parsley, yarrow, zinnias, and other nectar bearing plants.

For more information, on butterfly gardening, contact your local CSU Extension Office.
Sixty-Second Secrets for Gardening Success is a production of Colorado State University Extension.
CSU Extension: Extending knowledge, changing lives.

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Colorado State University Extension, U.S. Department of Agriculture and Colorado counties cooperating.

Monday, February 24, 2014

Soil Testing: It's a good thing

Posted by: Alison O'Connor, horticulture agent, Larimer County

Spring is coming and gardeners are itchy to get outside and start planting. You've received seed catalogs for months now, and you’re totally over the wind and cold. I guess we should be glad that we don’t live in Minnesota (sorry, mom and dad). There is one thing you can do to get your hands dirty (literally) and prepare for the 2014 gardening season—do a soil test.

If you've never done it before, it’s a good baseline to start with. If you've gardened for years and keep adding organic matter, fertilizer, cover crops, etc., it will be a great indicator if you need to continue those practices. Soil testing, especially in vegetable gardens, should be as routine as planting peas in the spring. Plus, it’s really easy to do—the soil lab does all the tough work for you.  Follow the steps below to ace the soil test:

1. Gather your tools. In this case, I’m using a soil probe (but you can use a shovel or trowel), a plastic bucket and a container for submitting my soil sample. Some Extension offices may have probes that you can borrow or rent for a small fee. It’s really important that your bucket is clean and made from plastic—metal (especially rusted metal) can interfere with your results. The sample jar I’m using is one the CSU Soil Testing Laboratory provides (available at your local Extension office), but a quart-sized zip-top bag will work, as will paper bags.

2. Scout your area. In this example, I’m taking soil samples from a lawn, but this could be your garden, landscape bed or any other area you wish to test. If you’re having “problem areas” in a lawn or garden, then consider testing that section separately. Yes, you’ll have to pay for two soil tests, but it might be worth it—especially if you've had continual problems growing in that spot.
The lawn can be dormant;
soil may be sampled anytime the ground isn't frozen.
3. You want to get a representative sample from the entire area. You can do this by pulling at least 12-15 samples, which you will mix together. For the lawn, you’re looking for cores about 4” deep (or collect aeration cores and use those—just be sure to remove the thatch and grass).  In the vegetable garden, use a shovel or trowel to sample about 6” deep. Gathering multiple samples, mixing them together and submitting a subsample of the soil collected will be key to a successful soil test.
Gently push down on the probe to 4-6" deep.
Sample of soil pulled from the turf.
Remove the thatch and grass from the soil core.
4. Gather all your samples together in the clean plastic bucket, break up the big clods and then mix well. Remove any large roots or rocks. Fill your sample container with a portion of the mixture and put the rest of the soil back in the garden (or on the lawn).

Chunky cores.
Cores broken up.
Pour your sample into your sampling jar or baggie.
5. Do not send the lab wet soils, so let your sample air-dry for a few days before packaging it up. Then send it off for analysis. A routine soil test at CSU will cost $31 and includes pH, soluble salts (EC), nitrogen, phosphorous, potassium, organic matter, soil texture, iron, sulfates and some micronutrients. Or you can pick and choose what you want to test for. Some gardeners in flooded areas are testing for heavy metals, which is an additional charge. You should get your results via email in 7-10 days.
Let your soil sample air-dry for a couple
days before submitting to the lab.
6. A soil test will not tell you about pesticide residuals, toxic compounds, microbial activity, water requirements, compaction levels or why you cannot grow tomatoes worth a darn.

7. While CSU is a great place to test your soil, there are other private labs that can do the same thing. CSU Extension Fact Sheet #0.520 “Selecting an Analytical Laboratory” lists multiple places for you to consider.

In the next blog, Tony Koski will explain how to interpret and use your soil testing results. Numbers are great, but what do you do with them? And will it lead to your best tomato crop ever?

Wednesday, February 19, 2014

Sixty Second Secrets for Gardening Success: Houseplants: Rubber Plant

Today on Sixty-Second Secrets for Gardening Success: Rubber plant.

If you’re looking for an easy to grow plant for your home or office, consider a rubber plant. Rubber plants are long lived plants which adapt quickly to the conditions in your home or office.
Just be sure that night time temperatures do not drop below 65 degrees Fahrenheit.
Because rubber plants don’t like to have wet feet, plant in a pot that has a saucer and drains well. Remember to water and fertilize regularly and after watering, drain any excess water out of the saucer.
If your plant is in a warm, brightly lit location, remember that it will require more frequent water, fertilizer, and repotting.
To keep the leaves clean, simply wipe off with a moist rag. For extra shine, spray the leaves with a leaf shine product available at your local nursery or garden center.

For more information, on houseplants, contact your local CSU Extension Office.
Sixty-Second Secrets for Gardening Success is a production of Colorado State University Extension.
CSU Extension: Extending knowledge, changing lives.

Tuesday, February 18, 2014

The Diamond of the Plant World

By Carrie Shimada, Weld County Extension

They come in white, yellow and pink.  They are beautiful, exotic, and sexy; and while they do not cost two month’s salary- they are often linked to status.  Yes. . . .Orchids, are the ultimate in plant couture.   With over 300,000 licensed cultivars, the orchid is to the plant enthusiast, as the diamond is to the gem-lover- rare, long-lasting, and a symbol of beauty.
Orchids typically carry the stigma of being a difficult plant to grow, but with a bit of care, anyone can be successful at growing an orchid, even though they could be considered the plant world’s diamond.

There are a few species of orchids that fare well as a houseplant:  phalaenopsis, cattleya, and dendrobium, and cymbidium– each with their own characteristics.

Phalaenopsis species, or the moth orchid, are the most elegant indoor orchids.  They have long arching sprays of flowers that bloom in winter and last for several months and they adapt well to the home setting. 
Cattleya species are commonly used in corsages.  They bloom once per year in the spring or fall and the flowers last anywhere from 2-6 weeks. 

Dendrobium species bloom during the fall or winter and they remain for 3-4 weeks. Their floral displays are showy, long sprays of white, lavender, or a combination of the two.

Cymbidium species have thick, waxy petals, with petals ranging from one inch to five inches in diameter and they can have up to 20 flowers on one stem.
Orchids prefer normal household temperatures of 65F-70⁰F during the day.  But during the night, temperature requirements vary by species:  phalaenopsis like 65⁰F, cattleya, 60⁰F, dendrobium, 52⁰F, and cymbidium, 58⁰F.

 In short, they should be fine in your house during the normal night-time temperature.  Just don’t leave them in a window during a winter freeze.

Phalaenopsis species thrive under low light levels.  They perform best in bright windows with little or no direct sun, such as an east-facing window.  They can also be grown in artificial light, such as in an office setting.

Cattleya and Dendrobium species grow best in bright light to some sun.  They do not like direct midday sun, but they do like a slightly shaded south or west-facing window.

Cymbidium species have very high light requirements- a south facing window is best.


If you want to kill your orchid- let it sit in a waterlogged pot, as overwatering will kill your plant.  To avoid this, follow a couple rules:

-When orchids are actively growing, water once a week and allow them to dry slightly before the next watering.  Unless it is of the phalaenopsis species- they do not like to dry out.
-When watering- apply enough water to get water to drain from the bottom of the pot.
-When the orchid is done flowering, reduce watering.
-Do not allow water to remain on the leaves of your orchid, as this may lead to disease.

When orchids are actively growing and flowering they need to be fertilized on a regular basis.  Be sure to follow the fertilizer label- over fertilization will quickly kill your orchid.

Fertilize once a month using a water-soluble fertilizer.  Select a 30-10-10 fertilizer if your orchid is grown in a bark media; select a 20-10-10 fertilizer if you orchid is growing in any other medium.
After flowering, reduce fertilization until new leaf growth appears.

Orchids prefer an environment with 40-60% humidity; since that is too humid for your home ( we live in Colorado after all) it is important to supplement the humidity.

Placing the orchid pot in a tray of pebbles with a small amount of water, having a humidifier in the room, or occasionally misting the orchid with distilled water can supply your orchid with the needed supplemental moisture.

Planting Media
Do not plant your orchid in regular potting mix- this will kill the plant.  Since most orchids are epiphytes, they grow best in soilless mixtures with bark or cork. (Epiphytes are plants that grow by attaching themselves to tree bark in order to absorb water and nutrients.)  Orchid planting mixtures are commonly available on the market- it is best to use these, as they will provide the orchids with good aeration and drainage.

As with any brilliant diamond- beauty and grace require care, but the payoff is big.  The long-lasting, sometimes fragrant, and always elegant orchid may not fit in a small blue box, but they will add a bit of sexy to your home without the hefty price. 

Tuesday, February 11, 2014

Chickens in the Garden

Micaela Truslove, Broomfield County Extension

My husband and I jumped on the urban poultry bandwagon about two years ago, and we haven’t looked back. Once you get used to the saffron-yellow yolks of homegrown chicken eggs, there’s no going back to the watery, pale yellow grocery store variety. You’ll find no shortage of articles and books touting the benefits of raising your own chickens, and though they do have their challenges, the garden can benefit from a backyard flock.

Compost: Now that it has the nearly undivided attention of our girls, our compost has never looked better. The chickens spend the majority of every day in the compost pile rototilling the contents into wonderful black humus. Hours and hours spent scratching and turning means our compost is done in at least half the time. While they are in the pile scratching around, they are also incorporating their manure. The bedding and manure from the coop also go into the pile each time I clean it out. I try to keep this in the “holding” rather than the actively cooking pile so they don’t have access to it right away. I slowly add the mostly composted material from the bottom of the holding pile into the cooking pile.

Chickens are very curious and get up to all kinds of 
antics. Photo: Micaela Truslove
There are also other chicken byproducts that make it into the pile. Crushed eggshells go out with the kitchen waste and feathers from the bedding and their daily activities are also added. Though eggshells are rich in calcium, studies have shown that they don’t make any significant difference when incorporated roughly crushed. They need to be finely ground, which is more than I’m willing to do. Our soils also tend to be rich in calcium already. If there is a deficiency, as evidenced by symptoms such as blossom end rot in tomatoes, it is usually due to uneven moisture, which inhibits uptake by the plant.

One important note on chicken manure – it should be composted before going into the garden, just like any other manure. This is especially true if the manure is going anywhere near edibles. There are crops that are more risky than others as far as food-borne pathogens are concerned. Those fruits and vegetables that are in direct contact with the soil are more likely to be contaminated than others, and care should be taken to wash produce thoroughly.  This goes for any manure. To avoid possible contamination from harmful bacteria such as E. coli and Salmonella, do not harvest crops for at least 120 days after adding fresh manure.

Weed control: I have to say that this has been a very marginal benefit. One of the things on the top of my “reasons to get chickens” list was that they would help keep the weeds down. It is true that they are voracious omnivores, but they have shown little interest in the most problematic weeds in our back yard. Maybe they’ve decided that there is a steady enough stream of good stuff coming from the house that they needn’t bother with the twisting forest of bindweed that we are plagued with (dang it!).

However, they are fantastic at keeping the lawn nice and short. Grazing is another favorite activity, and they eat grass until they are literally stuffed with it and the blades of tender green shoots protrude from their beaks because their bellies are literally too full to swallow any more. If chickens suffer from a vice, it is most definitely gluttony.
Eating a container of yogurt and fruit that
spent too long in the fridge. With chickens,
nothing goes to waste! Photo: Micaela Truslove

Insect control: We never tire of watching our girls going about their business. They are incredibly curious and a little dippy, which makes for hours of entertainment. One of their favorite pastimes is chasing insects that manage to find their way into the chicken yard . They race around with the unfortunate morsel hanging from their beaks with the rest of the flock in hot pursuit. For some reason they never just gulp it down when they catch it, so there is always a game of keep away before the insect is finally consumed. If I find an army cutworm hiding at the base of a small plant or a grasshopper munching on my lettuce, into the chicken yard it goes and hilarity ensues. They spend a good deal of time after an irrigation tugging on worms in a cartoon-like fashion.

One trend that I recently discovered is the idea of having a “chicken moat” around the perimeter of the garden. The thinking is that the chickens will intercept many of the insects trying to enter, hunting them down like a pack of velociraptors from a movie. They really are quite effective at this, and very quick. It also means that they do not have free access to the garden because they don’t quite understand that it is okay to eat mallow, but I would rather they didn’t decimate the rest of the veggie patch, which they’d do in minutes if allowed. So the pictures you see on Pinterest of perfect raised bed gardens with nasturtiums spilling over the edges and chickens roaming the perfectly manicured pathways politely plucking bugs from the plants while leaving them intact is misleading at best, at least that has been my experience. 

As far as using crushed eggshells as slug control, there are mixed reviews as to their efficacy. Slugs are sensitive to irritants such as diatomaceous earth, which wound their slimy outer coating causing them to desiccate, the evidence is mixed as to whether or not eggshells perform the same function.

Though there are a few challenges to having chickens roaming the garden, we have found that there are great benefits as well, not least of which is the entertainment value. If you are thinking of getting a backyard flock of your own, my advice is to limit their access to desirable plants and instead give them their own space. Allowing them access to the compost pile will do wonders, and will save you a sore back from having to turn the pile regularly. They will keep your insect problems in check and provide plenty of nitrogen-rich manure. One study from the University of Missouri found that one four-pound chicken produces a whopping 28-80 pounds of manure every year! And you certainly can’t beat the fresh eggs.

Thursday, February 6, 2014

It is cold! Plant Hardiness

Posted by David Whiting, Department of Horticulture & LA, Colorado State University

It is cold today.  Let’s review winter hardiness.

Hardiness refers to a plant’s tolerance to cold winter conditions.  Low temperature is only one of many factors influencing plant hardiness.  Other factors include:

·       Photoperiod – The photoperiod (increasing length of the night) is the first signal that trees receive that winter is approaching.  This is of special concern when the parent stock of woody plants is selected from southern latitudes then planted in more northern areas.  The change in photoperiods may not properly trigger the beginning of the hardening for the tree.

·       Genetics – Plants have a genetic minimum that they can survive.  However, this will be trumped by temperature patterns over a multi-week period and short-term temperature swings.

·       Low temperatures – Temperatures this week may cause problems on some less hardy plants.

·       Recent temperature pattern – Hardiness is a factor the temperature the past few weeks.  Trees significantly increase hardiness when the temperatures decline slowly over a period of week.  When I lived in Minnesota, it was interesting how many plants were tolerant to the extreme cold (-20° to -30° F common) that are not hardy in Colorado.

·       Rapid temperature changes – Plant are rather intolerant of rapid temperature swings, so common of the Colorado winters with spring weather one week and a sudden return to winter.  This is the factor that most limited our plant pallet for Colorado.

·       Moisture – Trees loose about 20° hardiness when they go into winter with dry soils.

·       Sun and wind exposure – In our sunny climate, bark temperatures on trees can heat to 70° to over 80° in the winter sunshine.  Then freeze at night.  This leads to winter bark injury.  On evergreens, exposure to constant wind is a major hardiness issue, dehydrating the needles. 

·       Carbohydrate reserve – General plant health plays into hardiness.  Plants with a good supply of stored photosynthates are more hardy then plants that experienced growth limiting factors the pervious summer.

The USDA Hardiness Zone Map indicates the average annual minimum temperature expected for geographic areas.  Keep in mind the map is looking regionally, and does as does not take into account the microclimate changes in your elevation, drainage, exposure (aspect), or thermal heat loading.  So, in mountain communities, the zone for your area may not reflect the actual microclimate of your yard.  Actual microclimates maybe one or even two zone warmer or cooler.

Examples of Winter Injury
  •  Bud kill and dieback – From spring and fall frosts or from extreme low temperatures.
  •  Root temperature injury – Roots have limited tolerance to sub-freezing temperatures.  Roots receive limited protection from soil, mulch, and snow.  Under extreme cold, roots may be killed by the lack of snow cover or mulch.  Perennial flowers that are hardy under snow cover, may not survive the winters without snow cover and thus become an annual rather than a perennial.
  • Soil heaving – The freeze thaw cycle of the soil can push plants out of the soil, breaking roots.  Protect with snow cover or mulch.
  • Trunk injury – This is common on the southwest side of tree and is directly linked to drought.  This is more common on trees with hardscape over the rooting zone and soil compaction limiting the water infiltration into the rooting zone.
o   Sunscald – Caused by heating of bark on sunny winter days followed by a rapid temperature drop, rupturing cell membranes in the freeze thaw cycle.  
o   Frost shake – Separation of wood along one or more growth rings, typically between phloem (inner bark) and xylem (wood), caused by sudden rise in bark temperature.

o   Frost crack – Vertical split on tree trunk caused by rapid drop in bark temperature. 

Southwest bark injury is linked to drought stress.  It is common on trees with a restricted root spread or hardscape over the rooting area (restricting water infiltration into the root zone).

Winter injury on evergreens

  • Winter drought – Water transpires from needles and cannot be replaced from frozen soils.  It is more severe on growing tips and on the windy side of trees.
  • Sunscald – Winter sun warms needles, followed by rapid temperature drop rupturing cell membranes.  It occurs typically on southwest side, side of reflected heat, or with sudden shade.
  • Photo-oxidization of chlorophyll – Foliage bleaches during cold sunny days.  Needles may green-up again in spring. 
  • Tissue kill – Tissues killed when temperatures drop below hardiness levels.
Winter drought, sunscald, and photo-oxidization of chlorophyll are common on arborvitae.  This is a poor plant choice for this windy site with little winter moisture.

Monday, February 3, 2014

Musings on Once-blooming Houseplants By Irene Shonle

My Amaryllis is just about to bloom (maybe a little late for the holidays, but perhaps just in time for Valentine's day).   I try to enjoy it for as long as it lasts (moving it down into the cooler downstairs to prolong the show), but it is always fleeting.

Amaryllis in full bloom
This got me thinking about all the room I give to plants that bloom but once a year. I water them, feed them, make sure they have their happy amount of light, watch for insects, and in general, worry about them for the entire year.   They spend most of the year as just greenery, and then shine for a just a few short weeks.  Other plants in this category are my Epiphyllum ‘cactus’, my night-blooming jasmine (Cestrum nocturnum), and some of my orchids.

Are they worth the space they take up and the care I lavish on them?  What about my more quotidian plants like my faithful geraniums, which are almost never out of bloom, or my heliotrope, which blooms in regular cycles? Or even my Amazonian lily (Eucharis amazonica) and Chinese perfume plant (Aglaia odorata), which bloom more sporadically, but usually at least twice a year?  Should these plants not be even more appreciated, because they are always providing me cheer, even in the depths of winter?  
Orange Amaryllis and Pelargoniums (Geraniums)

There are other reliable houseplants that are sporadic bloomers or even everbloomers (crown of thorns (Euphorbia milii) some Hoyas, Lipstick plant (Aeschynanthus radicans) that I don’t grow, which also qualify as the workhorses of the houseplant world.  Also in the long-blooming category is the heavenly-scented Osmanthus fragrans, which I grew and dearly loved for years, until it suddenly crashed and died.  Still not sure why.  The flowers were not conspicuous, but they carry one of my favorite scents ever.  And for people with the right conditions (and perhaps a green thumb), African violets, jasmines, and gardenias can all do well.  Not for me --  they are happiest in high humidity, but others might have better luck.  I do grow Bougainvillea, but they only bloom well for me in the springtime, but I think if I had better sun, they would be a longer bloomer.  

But back to my once bloomers.  I think perhaps they’re wonderful simply because you have to appreciate them now.  I love the sense of anticipation as the big stem of the Amaryllis pushes up from the pot, and the buds slowly unfurl into splendor.  If I don’t take the time to slow down and admire, I’ll miss it.  And have to wait a whole year!

 As my Epiphyllum “Unforgettable” comes into bud in the spring, I greedily count the buds, waiting impatiently for the show. And what a show – each flower lasts no more than a day or two, but they are so improbably Dr. Seuss-like and brilliant, and there are so many in succession, that it truly is “unforgettable.”  I have even been known to take guests up to my sunroom to admire it in full bloom.

Epiphyllum 'Unforgettable"
And I wait all year for the heavy, sweet scent of the night blooming jasmine to fill my bedroom – it always seems to be triggered into blooming when I bring it into the house after a summer outside.
Night blooming jasmine (Cestrum nocturnum)

Yep, I guess those once-bloomers are worth it, after all.  But I won’t be giving up my workhorses, either.