CO-Horts Blog

Monday, September 30, 2019

Reflections on a season of indoor gardening

Posted by: John Stolzle, Jefferson County Extension
This post details what can happen when a plant enthusiast with a will to tinker moves into an apartment. In this post, I have overviewed some of the setup, challenges, current outcomes, and tips gleaned from my trials with indoor gardening. 

moved into an apartment about a year ago. It had one large south facing window which was light limited by surrounding structures. It had no patio, nor space to grow plants outdoors, nor were there open community garden patches nearby. Slowly, in the back of my mind, the urge to cultivate my apartment space grew. I eventually purchased a few houseplants, yet, I was unsatisfied. I wanted to tinker, I wanted a challenge, I wanted to pick fruit and see flowers. 

One morning, I decided that I wanted a garden and that apartment life was not going to stand in my way. I had grand visions of tomatoes and peppers in winter. I wanted a challenge and a challenge is what I got. 

Early March 2019 - Late September 2019 (Click to enlarge)

Stage 1: The Set Up

Plants need a whole bunch of things to thrive, but for the sake of this post I am going to drastically simplify them as: Soil, Water, Light, and Space. 

I began with a garden plan in my mind; however, most of my plans went out the window as soon as I first arrived at a nursery. There were just too many possibilities and so I opted to make a game out of my garden – What could I keep alive in this plant-unfriendly environment? 

Due to ad hoc planning and prep, I made multiple trips to hardware stores and nurseries; it was fairly inefficient, but I eventually ended up with a selection of plants, containers, and soil. I drilled drainage holes in the bottom of 5 gallon HDPE buckets (for tomatoes and peppers) and purchased short lipped storage bins to catch water. Beneath the storage bins and lids, I placed paper towels to help monitor for moisture and facilitate sliding the containers around. I have heard reports that moisture can seep from terracotta/clay containers and damage floors, and so all of the plants were placed on plastic lids or in bins. 

Note: If I were to restart the project, I would use boot/shoe trays sold at hardware stores. They would likely be less expensive, and I believe that they would be easier to position in such limited space. 

Note the white growth on the soil in the picture on the right; this a type of saprophytic fungi which feeds on decaying plant matter (generally not a major concern for plants). 

Here are some references for starting out
* Container Gardening (Great Overview);
* Vegetable Gardening in Containers (Space);
* Soil (Potting soil is important!);
* Watering:
* Light:
* Insect Control:

Stage 2: Environmental Modification

After a month, many of the plants began to show significant stress. Some were spindly (in search of sunlight), the Asiatic Lilies were succumbing to disease and hadn’t grown but 2 millimeters, and the Lamb’s Ear was slowly losing its leaves. The plants had been carefully watered, planted in decent potting soil with room to grow, but needed more light. 
I thought it would fun to try growing a Mammoth Sunflower (Helianthus giganteus); the kind that can grow 10ft+ tall. It grew 3 feet with artificial support, flowered and then died shortly thereafter.
I eventually acquired and installed a broad spectrum led grow light; the plants didn’t rebound quickly but they did show signs of increased vigor… And then I began to notice the insects. 

I had attempted to avoid an insect outbreak by rinsing the foliage of each plant in my kitchen sink and then spraying some of the plants with Neem oil and/or insecticidal soap. Despite my best efforts, I have found myself locked in battle with aphids and spider mites. In this protected environment, the pesky bugs are able to feed and reproduce without a check or pressure from predators. At one point, I considered releasing predatory insects but then had visions of Cane Toads in Australia… I have so far opted to not venture into this territory, though I am very tempted.

Wiping down and then spraying the plants does seem to provide a brief reprieve from the infestation. I currently believe my challenge of aphid and spider mite management to be two-fold: 1, I occasionally re-infest my garden with new insects as I add different/new plants (to replace those which didn’t make it), and 2, my soap and horticultural oil treatments need to be better timed.  

Additional References

Additionally, I have learned that many potting soil mixes come pre-packaged with fungus gnats eggs. Upon adding water, these eggs hatch, and adults will soon be flying all around indoor environments.  These insects are very minor plant pests, but can be an incredible nuisance. I have had huge success managing the insects with yellow sticky paper; noted in this factsheet on Fungus Gnats: ://

To any adventuresome gardeners considering an indoor garden, I had the greatest struggle with: Asiatic Lilies, Snap Dragons, Sunflowers, Sweet/sugar Peas, Daffodil bulbs, and ornamental grasses. The grasses struggled and failed in the most spectacular fashion.

The tomatoes and peppers seem to struggle up to a certain point of development, after which they grow quite rapidly. The Scotch Bonnet (nursery started) has done amazingly well. It did have a significant set back due to an insect outbreak and me burning it with oils, but three weeks later, it is now flowering again. I have also been surprised by how well the Bougainvillea, Mandevilla, and Pineapple have done.

Stage 3: Success?

What does success look like in a mad-gardener’s laboratory?  I have lost many plants along the way and have added some fun new players such as Purple Passion Gynura aurantiaca, Lavender, and Taro. It has been a worthwhile experiment in my mind. Yields have been low, but my vegetables are just starting to produce... And who knows, maybe I’ll have fresh tomatoes in winter. 

A bit of gardening chaos; perhaps it's time for a mid-season prune.
I have many tales to tell from my trials with indoor gardening: of tomato training, of the importance of wind and humidity, supplemental lighting, container rotation, fertilizing, and manual pollination...  Perhaps this will be the first in a series of indoor gardening blog posts.  

For more information on houseplants, check out this blog posted last Monday:

 Best of Luck in all your gardening endeavors! 
- John 

Thursday, September 26, 2019

High and Dry Garden

The High and Dry Garden
By CSU Horticulture Agent, Linda Langelo

In Akron, Colorado, we have a demonstration garden that shows the public what plants can tolerate an extended drought and still survive.  In some cases, even do well.  Last year we applied for a Colorado Garden Show Grant and received funding to renovate the garden.  It was first implemented in July 2005 by a now retired CSU Horticulture Agent, Joanne Jones.

Since 2005, we have watched the garden through the seasons to see which plants were able to tolerate the conditions and which plants did not.  The plants received supplement precipitation from Mother Nature.

The plants that survived and did the best are listed as follows:

Squaw apple--------------------------Peraphyllum ramosissimum
Oregon grape-------------------------Mahonia repens
Desert Colorado Four O'Clock----Mirabilis multiflora
Curl-leaf Mountain Mahogany----Cercocarpus ledifolius
Common Gaillardia-----------------Gaillardia aristata
Chocolate Flower-------------------Berlandiera lyrate
Provence Broom--------------------Cytisus purgans
Snow Mesa Buckwheat------------Eriogonum wrightii var. wrightii
Upright Blue Penstemon-----------Penstemon virgatus

I want to share two of my most favorite plants from the list above:

Squaw apple-- 
Photo Credit: Linda Langelo 

Squaw apple is in the rose family and is also known as wild crab apple.  It has endured without any extra care.  This could make a great hedge or backdrop for a garden.  It gets four to six feet tall. It attracts birds, bees and butterflies.

Desert Colorado Four O'Clock- 

Photo Credit: Linda Langelo

This is a no muss, no fuss plant.  Once it gets established it can seed itself in other places, but in our garden it has never been invasive.  It is a deep-rooted native plant.  It is filled with flowers from late May through the end of summer.  The flowers open in the afternoon.  It is hardy to zone 4.  It grows to 18" tall and spreads to 72" wide.  I would consider both of these plants underused.  They are great for conserving water.

The new plants that we were able to implement in the garden are as follows:

Silver Edged Horehound--------Marrubium rotundifolium
Undaunted Ruby Muhly Grass-Muhlenbergia reverchonii
Dark Knight Blue Mist Spirea--Caryopteris clandonensis 'Dark Knight'
Desert Sweet, Fernbush----------Chamaebatiaria millefolium
Apache plume---------------------Fallugia paradoxa

It is hard to pick a favorite or two from this list.  They are all great plants, especially when it comes to drought tolerance.  I really like the blossoms on Blue Mist Spirea.
Photo Credit: Linda Langelo
We ended up having chosen the right season to renovate this garden.  We had snow a week after the plants were in the ground.  Then we have had rain almost weekly or more through the season.  All the plants did well from the 29 degree Fahrenheit day with snow on the ground through this wet season.  

This garden is placed along our walking path in the Washington County Fairgrounds.  We also have placed a free library to hold our brochures, other Extension information and have a horticulture book exchange.  

Photo Credit: Linda Langelo
Without the funding from the Colorado Garden Show, this would not have been possible to give this garden a new "facelift".  We had community volunteers, Akron High School Science Students, Colorado Master Gardeners, office staff and the town workers, even the neighbor by the walking path participated in the renovation.  That is what makes a community.  As the garden grows I can take more photos and share them in a 2020 blog!  Stay tuned.....

Monday, September 23, 2019

"Plant Parenthood" - The rise (again) of houseplants

Posted by: Deryn Davidson, Boulder County Extension


Aaaaah, houseplants. My childhood homes were full of them. Both of my parents have green thumbs and it seemed that every nook and cranny had some lovely, green, leafy thing adding to the coziness of our abodes. Many of those same plants STILL reside with my folks and I'll just say that I grew up when MTV only played music videos and big hair and spandex were all the rage. Sometimes my chores included watering those plants and I always felt a little anxious that I was going to over-water one of the many, many pots and have to run for a towel and dry up the mess as it came cascading down out of the saucer. C'est la vie, it happens to the best of us! 

It's no surprise that once I moved out of my parent's home I began to fill my own with my collection of plants. Some I purchased, some I inherited and some were from cuttings that I took from office buildings, restaurants, college campuses, etc. What?!? Don't tell me  you never popped off a spider plant baby, stuck it in your bag and put it in a glass of water when you got home!!

Anyway, there are many, many houseplants available, depending on your lighting, your level of commitment and so on. They are great! They clean the air, bring life into a room, and some studies show they reduce stress and can boost creativity. Who doesn't want all that? Well, as it turns out, the millennial generation is hip to all this. Good on ya!! Sales of houseplants are up nearly 50% over the past few years and businesses attribute much of that to young folks (those in their 20s and 30s). I heard this figure as I was driving along listening to the radio recently. The show was one that typically covers some pretty hard-hitting topics in politics, religion, social justice issues, etc. But when I tuned in, what did I hear?? They were interviewing people about houseplants!! I was so excited!! I kept thinking this must be just a little 5 minute blurb, but no! The whole show was dedicated to it!! What fun for all the plant nerds out there. Apparently social media is playing a huge role in the rise in interest in houseplants. People like to show off their successes and find a community and support around caring for them. 

I highly encourage you to go to the link below and give a listen. You'll learn all kinds of interesting trends and other information about houseplants. Plus, it's just fun to hear a nationally syndicated radio program highlighting our indoor, foliage friends!!

The Perks and Perils of Plant Parenthood on 1A 

Six popular houseplants that help clean the air:

Chinese Evergreen


Spider Plant

Aloe Very

Peace Lily

Thursday, September 19, 2019

A Pesky Invasive That Can be Managed

Posted by: Nancy Klasky, Broomfield County Extension

You may have seen common mullein (Verbascum thapsus) scattered along roadways, mountain canyons, rangelands, or in forests. The tall stalky plant has yellow blooms gathered at the top and large sage-colored leaves at the base. It grows profusely after major disturbances like fire, construction, or flooding. Common mullein is an introduced species and is present in all 50 states and Canada. Originally brought to North America for medicinal purposes, it has been designated a C List Noxious Weed by the Colorado Department of Agriculture, which means it is up to private and public entities to manage. 

I got to learn a lot about mullein after the High Park Fire west of Fort Collins. This lightning- ignited fire started in June of 2012 and due to the hot, dry spring, it burned over 87K acres and destroyed 259 homes before being contained a month later. I worked on land in this area at the time and saw first-hand both the devastating effects of the fire and the renewal of the forest that followed. After all, when occurring naturally, fire is a cleansing process that actually keeps our forests healthy. If left unmanaged, accumulated duff (forest litter) and smaller shrubs and trees can create dense, overgrown forests that can cause cataclysmic wildfires. Some regular burning keeps this in check.
Common mullein before mitigation work.
Tiny seeds find their way into crevice of rocks and form first year rosette. 

The land I worked on is a mixed forest just over 8,000 feet in elevation. It’s primarily ponderosa pine, with some Douglas fir and aspen. Ponderosa pine evolved with the wildfires. Thick bark protects them from destruction by low-intensity fires, and natural loss of lower branches reduces “ladder fuel” that allows fire to climb to the crown of the tree. Much of the surrounding land was turned into a moonscape by the High Park Fire, with 100% mortality of trees and other plants. On the managed land, many ponderosa survived, but most other vegetation was destroyed. This created the ideal environment for common mullein to grow, and boy did it grow. Where once there was an abundance of wildflowers, kinnik-kinnik, and common juniper shrubs, there was now a forest of mullein.

Mullein seeds will survive a fire and can remain viable for 100 years! They may have been in the area for decades, unable to germinate until this disturbance. Worse yet, each of these plants can produce 100,000 to 250,000 seeds per terminal spike. I had my work cut out for me, but I was determined to see this beautiful property restored to its natural state. 

Common mullein is a biennial plant, which means it takes two years to grow to its mature height and bloom. The first-year plant is a basal rosette that stays low to the ground and does not flower. If the plant lives to the next year it will bolt up and bloom. Management techniques that work with this lifecycle are important to stopping the spread of this invasive plant and not exacerbating the problem. 
Last years deadheaded stalks with no new mullein growing!

Like I mentioned mullein likes disturbed ground, so how do you get a plant out of the ground without creating more disturbance? First, you only want to remove the plant if it is a first year rosette. The roots are shallow and usually easy to pull up. It’s important to try and press down the soil as you pull the plant out. Yanking the plant out will give the seeds you know are there a better chance. If the plant has made it to the second year, which was the case with many plants by the time we got to them, you want to cut the bloom off before it starts to dry and drop its seeds. With the help of great groups of volunteers we were able to make many trips to the property to work on the mullein issue. Each year we saw less of the plant come back, and each year we worked to remove what did pop up. With persistence and determination, we saw the native wildflowers, kinnick-kinnick, and juniper shrubs take back what was theirs! The beauty of the restoration is when the native vegetation grows back, that is enough to keep the mullein from growing. There are other management options to consider, but I found the mechanical removal of this plant the best one for this area. 
The property with it's natural vegetation having taken back over.