CO-Horts Blog

Monday, November 25, 2019

BEE Thankful for Pollinators

Posted by: Lisa Mason, Arapahoe County Extension

We have so much to be thankful for this holiday season including the meals we eat. Have you ever wondered how much of the food on our tables is dependent on pollinators? Approximately 1/3rd of our diet is dependent on pollinators, including some of our most nutritious fruits, vegetables, and nuts. Even our meat and dairy industries depend on pollinators because bees pollinate alfalfa and clover, which are food sources for cattle. (Food staples like corn, rice, soybeans, and wheat are either wind-pollinated or self-pollinated.)
Honey bees (Apis mellifera) are important food crop pollinators. Some species of bee flies (Bombyliidae family) can also pollinate crops. Photo: Lisa Mason
As you plan your holiday meals with family and friends, we can think about all the delicious foods we have because of pollinators. Here is a list of common food items and who pollinates them provided by The Pollinator Partnership:
  • Almonds - Honey bees
  • Anise – Honey bees
  • Apples - Honey bees, blue mason orchard bees
  • Apricot – Bees
  • Avocado – Bees, flies, bats
  • Blueberry – Over 115 kinds of bees, including bumblebees, mason bees, mining bees and leafcutter bees
  • Cardamom – Honey bees, solitary bees
  • Cashew – Bees, moths, fruit bats
  • Cherry – Honey bees, Bumblebees, Solitary bees, flies
  • Chocolate – Bees, flies
  • Coconut – Insects, fruit bats
  • Coffee – Stingless bees, other bees, flies
  • Coriander – Honey bees, solitary bees
  • Cranberries – Over 40 bee species
  • Dairy – Dairy cows eat alfalfa pollinated by leaf cutter and honey bees
  • Fig – Over 800 species of fig wasps
  • Grape – Bees
  • Grapefruit – Bees
  • Kiwi fruit – Honey bees, bumblebees, solitary bees
  • Macadamia nuts – Bees, beetles, wasps
  • Mango – Bees, flies, wasps
  • Melon – Bees
  • Nutmeg – Honey bees, birds
  • Peach – Bees
  • Pear – Honey bees, flies, mason bees
  • Peppers – Bumble bees
  • Peppermint – Bees, flies
  • Pumpkin – Squash and gourd bees, bumble bees
  • Raspberry and Blackberry – Bees, flies
  • Strawberry – Bees
  • Sugar cane – Bees, thrips
  • Tea plants – Flies, bees, and other insects
  • Tequila – Bats
  • Tomato – Bumble bees
  • Vanilla – Bees
Note: This list is not comprehensive. Many other crops also require pollination by insects and animals.
Some species of leafcutter bees (Megachile spp.) are important crop pollinators. Photo: Lisa Mason
Now you can quiz your friends and family over the holidays about what foods are dependent on pollinators.  

Have a safe, healthy and happy Thanksgiving!  

Thursday, November 21, 2019

Trials of Indoor Gardening pt.1: spider mites, aphids, and thrips oh my...

Posted by: John Stolzle, Jefferson County Extension
One of the best things about indoor gardening is being surrounded by green foliage during winter. But this also brings a potential for pests to thrive 365 days a year.

The indoor garden remains unaffected by an early season blizzard; fresh produce as of this publication date!
One of the greatest challenges my garden has faced has been a battle against aphids and spider mites. In outdoor environments, natural predators do much to keep populations of pests (like aphids and spider mites) in check. But in the climate-controlled world of an indoor garden or greenhouse pests can reproduce unchecked by predators and lead to imbalanced (aka. out of control!) populations.

Where did they come from?
With a few exceptions, plants which I started from seed have remain unscathed; however, a few plants which were placed next to incoming nursery stock encountered problems.
Damage from inadequate watering and spider mites on a Jalapeño
Case in Point: one poor Jalapeño (photo above) that was started from seed caught a bad case of spider mites from another pepper plant which was purchased from a commercial nursery/greenhouse. Initially things in the garden were great but while I went away on vacation, insects were busy chowing down on my pepper plants. I returned to what you see in the picture.

Some time after this, I purchased a sad looking (#discount) Taro plant. I placed it in the garden, wiped off its leaves and stalks with a damp paper towel, and watched it closely. After some weeks, I began to notice many tiny glistening, sticky spots on its leaves; the spots were honeydew, evidence (waste) left by aphids. I took a closer look (picture below) and saw tiny green insects (aphids) moving around the leaves.

Aphids on a Taro leaf
A lack of patience.
One pepper which had become infested with spider mites appeared to stop growing after treatment. I became frustrated because it hadn’t produced a new leaf over the course of two months! So, I decided to rip out the pepper and use the pot for something else.
Pepper plant after 3 months of growth in an 18cm (7in) diameter pot.
Little had I known that the plant had been developing a very robust root system. Sigh.. a root system that would have been able to support many specialty peppers. On the flip side, now I know the plants are growing and that this container was likely too small for the plant anyway. Recommendations for adequate container sizes can be found here

What can be done... aside from tearing out a plant?
It is important to first know what may be attacking a plant. For example, after looking for some time (phone cameras, magnifying glasses, hand lenses, and microscopes can be helpful!) I observed not only spider mites but also thrips on my pepper plants! These two insects require slightly different management strategies. Note: Information on thrips is linked-to at the end of this post.

Spider mites and aphids lay eggs on plant material and go through a roughly 2-week life cycle (important to know when planning follow-up treatments). A jet of water is often enough to dislodge these pests from many plants. Have a spider plant (‘Chlorophytum comosum’with spider mite webbing between its leaves? - Give it a shower in the sink!

It is easier to battle 10 insects than it is 10,000. Washing a nursery plant upon its arrival can save headaches  by preventing major outbreaks from ever occurring. Note: Not all plants like to have wet leaves. It can be helpful to look up a plant’s general care recommendations.

Insecticide products do exist for treating spider mites, aphids, thrips, and other various plant pests. Insecticidal Soaps with the active ingredient Potassium Salts of Fatty Acids, and Horticulture Oils (e.g. Neem, Cottonseed) can be effective parts of an integrated pest management strategy. It may not seem like it, but Insecticidal Soaps and Horticultural Oils can be harmful to humans and pets and other non-target organisms. Pesticide product labels should always closely be followed and adhered to. Note: when applying an insecticidal soap (active ingredient: 'Potassium Salts of Fatty Acids') any insect not completely wetted (e.g. an aphid hidden in a rolled up leaf) will not be affected.

What I wish I would have known.
  • That placing plants in the shower or sink or (even better!) taking them outdoors prior to treatment can make cleanup a much easier process.
  • Some plants can react poorly to Insecticidal Soap and/or Horticultural Oil treatments. It can be mildly traumatic to see a plant drastically defoliate a day after being treated.
  • Yellow sticky pads can be incredibly effective at managing indoor populations of fungus gnats (sometimes mistakenly referred to as fruit flies).
  • Patience is key (in reference to the pepper I tore out).
For more information on a variety of topics, please see the links, below.

As a fun aside, insects (like 'Lady Bug' and Lacewing larvae) which feed on spider mites, aphids, etc. can be purchase from locations around the USA. Here is a very impressive list of BioControls and example locations from across the US where they can be acquired:

For an introduction to this indoor garden, please see this blog post:

 Best of Luck in all your gardening endeavors! 
- John 

Monday, November 18, 2019

Drought hits most of Colorado Again, pray for snow!

By Susan Carter
Here we go again.  Many of you remember the drought of 2017-2018, second worst on record.  Some parts of our state where there is no irrigation did not even bother planting crops; some areas were on water restrictions and then came the snow the winter of 2018-2019.  That was a godsend.  If we would have had two years in a row of severe drought, we would have been hurting for water resources.  With the winter snow and the wet spring, sources of irrigation and domestic water filled up beyond what was expected.  For a brief period, the entire state had no, zero, nada drought.  Then the drought started creeping up from the southwest corner again.  Now ONLY the north to northeast corner of Colorado is not in drought.  Note the Water year starts in October.
So what does this mean for your garden and perennial plants including trees?  Drought stress is not something that just goes away because you watered once or because for a brief period, the state was not in drought.  Water is one of the key ingredients in photosynthesis and other plant processes that help the plant create carbohydrates and move water and nutrients throughout the plant.  When plants cannot adequately produce food, they use up their reserves.  Each plant, like people, is different due to the environment and the type of tree as well as its specific genetic makeup.  So some plants will bounce right back, where others will stumble along for a few years before they give up because they have exhausted their resources.  In addition, stressed trees attract insects that can also exhausts the tree’s resources as they cannot fight off the insects or recover from the damage done.
Old Pinon Pine with IPS Beetles- Incorrect water stress
Photo By Tom Ziola
Leaf Scorch- drought can be a cause
Photo by Susan Carter

So how do we deal with drought that seems to come more often?  Well we can properly water, winter water, direct downspouts etc… to keep what we have alive.  Then we can start by replacing plants that have died with more drought resistant plants.  Remember, if you have a tree in a lawn and you remove the lawn and install rock what have you just done?  The root system of that tree is totally under the lawn.  A tree’s root system is at least twice its width or 2-5 times the height.  Ninety percent of the roots are in the top 12-18" of soil.  That area needs water.
Watering photo from CSFS
Trees are like people in that they do NOT like change.  To change a watering zone from frequent watering of turf to watering the tree root zone, you have decrease the frequency slowly.  You have to wean it off the watering to the appropriate 10, 20 or 30 day of watering interval for the type of tree and environment. (Watering Mature Trees)  I could go on with more ways to save water, but I think that is a blog for another day, the point is think about drought affects, where you water and why you water and come up with a long term plan. 

Snow around Plum trees
Photo by Susan Carter

In addition, we can hope for more snow!  If the ground is dry and frozen when the snow arrives, it does not hydrate the parched soil.  If the soil is dry, but not frozen water so there is moisture in the soil (but not saturated) so if it thaws again there is water available to the roots.  Plants need to go into the winter with moisture available to them as they continue to respire and give off moisture even if they have dropped their leaves.  Of course evergreen plants like pine and spruce trees, evaporate due to having leaves all winter.  A dusting of snow is not very helpful either.  It can just evaporate.  Snow at least 6” deep can insulate the ground and provide enough moisture when it melts to help.  Then there are the reservoirs that need to fill so we have irrigation and domestic water.  So let it SNOW!

Susan Carter is the CSU Extension Horticulture and Natural Resource Agent for the Tri River Area.

Monday, November 11, 2019

Ric Rac Orchid Cactus (Epiphyllum anguliger) by Irene Shonle

My fishbone or Ric Rac orchid cactus this year finally is large enough to have had a wonderful blooming period, and I am smitten!  The fall-blooming flowers are large and white with yellow-orange sepals, and are delightfully, waftingly, fragrant at night and early morning. To me, they smell like Easter Lilies mixed with a little citrus blossom - quite lovely.  The sad part is that each flower only lasts a day - two at the most, so you have make sure you are home to enjoy them. Cancel all out of town travel when you see the buds enlarging! I’m not sure you have to stage a viewing party like people do with their Night Blooming Cereus, but on the other hand, it doesn’t seem over the top, either. My cactus had two flushes of blooms this year, a couple of weeks apart. We’ll see if that is an ongoing phenomenon. 
Ric Rac Cactus flower (Epiphyllum anguliger)

Even out of bloom, it is a worthwhile specimen - the long stems have a unique foliage, giving the plant its common names.The flat, deeply lobed stems vaguely resemble a fishbone. It’s also so called ricrac orchid cactus because ric rac ribbon has that same shape.  The stems are long and arch before trailing downward, giving it a wild and slightly octopus-like appearance. It makes a terrific hanging basket plant!

 Epiphyllum anguliger is a cactus species endemic to Mexico, occurring as an epiphyte in evergreen forests in Guerrero, Jalisco, Nayarit and Oaxaca. Epiphytic plants actually grow on trees or other plants, and find soil and nutrients trapped in small pockets where the branches emerge from the tree trunk.

Epiphyllum anguliger is easy to care for and very low maintenance. I have found they are less finicky than my spring-blooming Epiphyllum which I wrote about in a previous blog ( The fragrant flowers open at night may last into the day on cool cloudy days.

The plants prefer partial to dappled shade or bright indirect light, making it easy for most households to find a location for them. They would NOT appreciate a south or west window.

Because they are epiphytes, they prefer a well-drained soil. They prefer to be somewhat root bound, so don’t pot them in a very large pot. They should not be kept overly moist in order to prevent root rot.  Allow the soil to become semi dry between waterings. They would appreciate a little extra water during the growing season (spring to late summer as a general rule) and should be kept slightly dryer when not in active growth (late fall and winter).  Give plants a brief rest at the end of each flowering period by watering only enough during the next two or three weeks to prevent the potting mixture from drying out. It can be fertilized with a weak cactus or orchid feed over the growing season every two weeks or so. Do NOT over-fertilize.

If your friends fall in love with your cactus after your viewing party, not to worry. The plant is easily propagated. Break off a stem and allow it to callous over a few days before planting. Put in a light soil mix and water lightly. Do not disturb until you see new growth. This may take over a month. 

The occasional unruly long stem can safely be cut back to shorten. New stems will usually grow right from the cut area, and this can help to increase the fullness of your plant. It will also give you a supply of branches for propagation.

You’ll need patience and a bit of room to let this plant come into its full glory, but you won’t be sorry you brought it into your house.

Thursday, November 7, 2019

2019 "Best Of" Winners Announced from CSU Annual Flower Trial!

Posted by Jim Klett, Professor, Department of Horticulture and Landscape Architecture, Colorado State University

Each year, the Annual Flower Trial Garden tests and analyzes the performance of more than 1,000 varieties of annual bedding plants in Colorado’s harsh growing conditions.  Dozens of expert evaluators rate the plants for vigor, growth pattern, bloom and other characteristics.  The trial results help home gardeners identify annual bedding plants that are most likely to succeed.  For more detailed descriptions and photographs, visit  The following are some of the winners selected from the 2019 trial: 

Best of Show – Dahlia ‘City Lights™ Purple’ from Selecta 
The dark foliage and flowers of this variety made a dramatic statement in the garden.  The growth habit had excellent uniformity with upright plants that did not flop despite overhead irrigation.  Plants had strong flower power and were favorites of the bees. 

Best Novelty – Begonia T-REX™ Ruby Slippers from Terranova
The huge red leaves had silvery edges that would make a great contrast for color and texture with other plants in the garden.  Plant is grown mainly for the foliage.  It made a very eye-catching plant for areas with dry shade and can be used in either the ground or in containers.

Best New Variety – Petunia ‘Headliner™ Dark Saturn from Selecta
The unique flower color was very impressive with a bold soft creamy yellow and a dark star shaped eye.  Plants had strong vigor and developed into a uniform blanket of blooms in the container.  Plants and flowers held up well in the heat. 

Begonia (shade) – ‘BK Collection Vermillion Red’ from Beekenkamp
The overall appearance was striking all through the season with a very intense, rich shade of red and abundant blooms.  In addition to the prolific flowering, blooms were double which greatly added to the overall show.  Plants had dark green foliage and were very uniform.

Begonia (sun) – ‘Tophat™ Pink’ from Syngenta Flowers
Plants had great vigor but maintained a very uniform growth habit.  Flowers were unusually large and very abundant which made them immensely popular with the bees.  Plants looked great in either the ground or container and only got better looking even into the fall.

Bidens – ‘Campfire™ Flame’ from Proven Winners
Flowers had beautiful shades of orange/red/yellow and fade to a nice rustic color.  Blooms were prolific and kept a solid canopy of color all through the summer and into September.  Growth habit was very uniform and the overall effect was quite striking in a container.

Digitalis ‘Pink Panther’ from American Takii       
This plant flowers the first year on compact plants with small foliage.  The heavy branching produced multiple spikes at one time and did not require pinching.  The sterile blooms are long lasting and attracts pollinators.   Pink flowers are abundant and very attractive.

Geranium ‘Clarion® Peach’ from Benary+
This regal type of geranium had large blooms with truly mesmerizing shades of peach, pink and white.  The uniform, mounding plants were covered by blooms all season long and were a definite show stopper.  Other entries in the same Clarion® series were also impressive with excellent vigor and flowering.

Impatiens – ‘Beacon™ White’ from PanAmerican Seed
Snowy white flowers covered the plant canopy providing a bright splash of color for shady areas.  The vigorous plants maintained a controlled growth for excellent uniformity.  The added bonus for the entire ‘Beacon™’ series is that they have strong resistance to Impatiens downy mildew which has devastated many Imapatiens walleriana in the past few years.

Lantana – ‘HAVANA Sunrise’ from Dummen Orange
This heat loving plant had good branching, large umbels of flowers over dark green foliage. The compact growth habit with prolific very attractive multi-colored flowers with shades of pink, cream and yellow makes it outstanding. It has a very uniform growth habit and looked great in a container.

Petunia (container) – ‘Crazytunia® Tiki Torch’ from Westhoff
Flower color was exceptional with a bold and colorful combination of red, yellow and orange.  Combined with strong plant vigor and abundant flowering, this entry was clearly a standout.

Vinca – ‘Soiree Kawaii Coral’ from Suntory
Tiny coral colored flowers were bright and prolific making an impressive display of color in either ground or containers.  Additional features were the small white eye on the bloom and glossy green foliage.  Plants stayed compact all summer long with no leggy branches.

Zinnia – ‘Zesty™ Scarlet’ from Ball Ingenuity
Vibrant scarlet flowers had great flower power with the abundant flowering and uniform growth habit.  Plants had excellent vigor and were disease free all-season long.

Monday, November 4, 2019

Where Do Bees Go in the Winter?

Posted by: Lisa Mason, Arapahoe County Extension

I have been asked a few times this season what happens to the bees in the winter. Bees and other insects have special adaptations, so their species survives from year to year. Here is a look at bee adaptations and life cycles in the winter time.

Honey Bees
Worker bees foraged all summer and into fall bringing in food reserves to last them the winter. When temperatures start to drop, honey bees huddle together to make a cluster and shiver their wings. Shivering provides warmth for the hive. Their main goal is to keep the queen warm so the colony can survive. The core temperature in the hive can be as high as approximately 91 degrees Fahrenheit. A healthy hive with adequate food storage is more likely to survive, which reinforces the importance of best beekeeping practices by the beekeeper all year. Read how to prep a hive for winter here.
A honey bee, Apis mellifera. Photo: Lisa Mason
Solitary Bees
Solitary bees live a one-year life cycle. During the life cycle, a female bee builds a nest underground or in a cavity. She will collect pollen and nectar to bring back to the nest. All the collected pollen and nectar is made into a ball called “bee bread” which will be all the food needed for one growing bee. The female lays an egg on the bee bread and seals up the nest. After the egg hatches, the larva will go through full metamorphosis from a larva, to a pupa, and on to an adult before emerging from the nest the following season. The lives ended for the female and male solitary bees we saw flying around this summer, but their brood is warm for the winter underground or in a cavity, and will emerge next summer.
An overview of the solitary bee life cycle. Graphic: Lisa Mason

A native bee emerging from her underground nest. Photo: MaLisa Spring
Bumble Bees
Bumble bees live underground or in large cavities and have a one-year life cycle, like a solitary bee. During the summer, new queens and male bees hatched. They left their colonies to mate. As temperatures dropped, the male bees and worker bees from the current season’s colony died. The new, mated queens found a place to rest and hibernate over the winter, usually underground. When spring arrives, she will emerge, begin to forage, build a new nest, and lay eggs. The eggs will mostly be female worker bees at the beginning of the season. The queen will continue to lay eggs throughout the season. In late summer, new queens and male bumble bees will hatch and leave the colony and the cycle repeats itself. Queen bumble bees are capable of living alone, unlike honey bee queens.
A bumble bee, Bombus sp. Photo: Lisa Mason
For more information on bee life cycles, you can read the Native Bee Watch Citizen Science Field Guide.

For more information on what happens to other insects in the winter, you can refer to this CO-Horts Blog post written by Jessica Wong.