CO-Horts Blog

Monday, June 29, 2020

The joy of sunflowers

By  Irene Shonle,  El Paso County Extension

This year I have really fallen in love with sunflowers. I have always liked them, but this year, I am in love. I love them because of their cheerful disposition, because they are so dang easy to grow, and even more because they are such great plants for the habitat garden.
Wild sunflowers in my garden (Helianthus annuus)

Sunflowers lure pollinators in with their tall form and bright-colored flowers and then  they reward them with abundant sources of both pollen and nectar. Both smaller bees and butterflies find an easy perch on their wide flat heads. Bees that are attracted to sunflowers include bumble bee, digger bee, large carpenter bee, small carpenter bee, leafcutter bee, sweat bee, plasterer bee, andrenid (miner) bee, and honey bees. Even the leaves of sunflower are a good source of food for a variety of butterfly caterpillars including American Lady, Silvery Checkerspot, and Gorgone Checkerspot. Later, the black, oily seeds provide food for a variety of birds such as finches, juncos, and chickadees.  Make sure to save a few seeds yourself to plant for next year.

Another reason to like sunflowers is to provide quick screening from neighbors.  If you have planted a slower-growing shrub or vine to block a view, but want more instant results, plant some of the larger sunflowers. Some of the ones in my garden are already 7 feet tall at the end of June!
Sunflowers (not yet in bloom) blocking the view of my neighbors while my apache plume shrub grows in 

You can also use sunflowers to create  a hidden, shady fort for children to play in.
Sunflower fort - picture from Pinterest

Some tips for growing sunflowers:
Plant in full sun.  Sunflowers, especially the wild-type sunflower, are drought tolerant, but will bloom better and grow taller with some water.  That said, I am astonished at how well the wild sunflowers are flowering here in our extreme drought and heat this summer.

Plant in groups to make it easy on pollinators to forage efficiently.  Don’t buy pollen-less single-stem varieties -- these are good for the cut-flower industry, but bad for pollinators.  Branched sunflowers are a much better bet, plus produce more blooms for you to enjoy.

Plant several different varieties to provide a continuous supply of flowers from late summer to fall. Look for “days to bloom” on the back of seed packets and plant a variety.  As a gardener, you can revel in colors ranging from yellows to oranges to reds, with wildly different sizes of plants and flowers. You can also sow sunflowers every couple of weeks in the spring to increase bloom time.
One of the many varieties of sunflowers you can grow - this just bloomed in my garden yesterday

Friday, June 26, 2020

I've got honeydew on my honey-do

Posted by: Todd Hagenbuch, Routt County Extension

The Futura will look brighter after a good wash.
(Well, after that and the paint job I'm pushing for...)
My honey-do list this summer is a long one. Of course, I put a lot of it on there myself, but it includes planting new gardens, tending to the lawn, weeding the existing gardens, keeping an eye out for the usual insects, (yes, I’m talking about you, Columbine Sawfly) and more. I even have some non-yard items on my list, one of which is convincing my mom that we need to restore her 1966 Ford Falcon Sports Coupe. That honey-do actually alerted me to an insect issue in my trees. How, you ask?

I took Mom’s car from her home a couple of weeks ago to get some estimates on the work. In the time since, it’s been in my driveway instead of in her garage. When I met her with the car to discuss the restoration, she questioned what had happened to her already-spoiled paint job. “Honey, what did you do?!?” she exclaimed. “This honey didn’t do anything, Mom,” I replied. “That’s honeydew.”

Nope, that's not custom paint- that's honeydew.
(At least it does bring some shine to the ol' girl!)
Honeydew? Yes, it’s a wonderful, sweet melon and my favorite scientist on the Muppet’s Show, but it’s also the term used for the sticky substance that is excreted from phloem-sucking insects. Scales, adelgids, whiteflies, and aphids all produce honeydew. They pick a spot on a plant leaf or needle and, with their specialized mouth parts, bite down and start sucking the phloem, or plant sap. As with all things eaten, what goes in must come out, and out it comes as honeydew. Then it floats down and finds its way onto things below it.

Like I did with the Falcon, you’ve probably parked a car under a tree seeking shade from the summer sun only to come back and find the windshield sticky with honeydew. Perhaps your deck and railing have become covered with the sticky substance, too, or the sidewalk under a tree. I get calls in the office asking what kind of tree it is that creates the honeydew, or what’s wrong with a tree that's ‘leaking’ sap from above. No one is thrilled to find out it’s actually insect poop that has covered their patio furniture or sunroof.

These shade seekers will find their windshields a sticky mess
at the end of the day as this cottonwood has aphids.
In most areas this time of year, aphids are the creators of honeydew. As one of the only insects that gives live birth, each aphid is born ready to birth to the next generation, and so on. This means that aphids multiply rapidly, and as more are born, more excrete honeydew. One day your deck is fine, and two days later, it’s a sticky mess. And just like that, your honey-do list now includes power washing the deck, scrubbing the outdoor furniture, and washing the car.

Honeydew does have its fans. The hum from the tree near the Falcon isn't the 289 V8 firing all cylinders, but Western Yellowjackets who feed on it and swarm the tree to find it. Ants love it, too, and will roam the plant or tree collecting it and protecting the aphids producing it. 

Plants can be sprayed with an insecticidal soap or pesticides to help control aphids, but I find that just spraying them down with a strong jet of water is effective and causes fewer issues for beneficial insects and the items below the tree. A hard rain will do the same thing and provide relief for a few days, but remember that the aphid population will rebound quickly. Spraying with water again can help keep numbers manageable.
A lower leaf from the cottonwood, sticky with honeydew
For detailed information on how to control aphids on shade trees, add reading CSU Fact Sheet 5.511 to your honey-do list. The control efforts you learn might enable you to knock a few of those other honey-do items of the page.

Thursday, June 25, 2020

Milkweeds, Garden Design and Monarchs

Photo credit: Butterfly Gardening

Have you ever wondered which milkweed is really recommended for our home landscapes?  There are only a 100 species across the United States to select, but the best is Asclepias speciosa or Showy milkweed.  One word of caution is that Showy milkweed does need space because it is considered one of the tillering species of Asclepias.   

Showy milkweed grows one and a half feet to three feet tall with blue-green pubescent or hairy leaves producing flower clusters or umbels of star-like rose colored to purple flowers in the upper axils of the stem.  It grows best in full sun with moist, well-drained soil that can be course, medium or fine. Its native habitat ranges from dry to moist savannas, prairies, roadsides, old fields, and meadows according to Lady Bird Johnson Wildflower Center. The plant has a milky sap when you break the stem, or the stem is injured in some way.  This milky sap is a latex and except for Asclepias tuberosa is found as a characteristic of milkweeds. This sap containing toxins is a defense mechanism for the plant to make the leaves unpalatable. This plant serves as a host for monarchs while hummingbirds and other butterflies feed off the nectar.

Other milkweeds to add to your home landscape can be those with NON-Aggressive root systems which are as follows:
  1. Asclepias incarnata or Swamp milkweed which is a native perennial growing three to four feet tall in full sun and consistently moist soils.  Flowering in July through August its blossoms are pale pink to rose purple.  Suggested cultivars are ‘Cinderella’ have pink to dark pink, reflexed petals, and pink to white crowns. ‘Ice Ballet’ is a white-flowering cultivar. ‘Soulmate’ has deep rose-pink flowers.  For further reading:
  2. Asclepias tuberosa or Butterfly weed a perennial which grows one to three feet tall in full sun and soil that is average well-drained soils dry to medium moisture. It does well in poor dry soils and tolerates drought. 

What would be the best arrangement or placement of milkweed in a garden?  Dr. Adam Baker of the University of Kentucky did research and presented that research in a paper titled, “Colonization and usage of eight milkweed (Asclepias) species by monarch butterflies and bees in urban garden settings,” along with Daniel A Potter, also at the University of Kentucky. 

In short, the small garden plots that were designed for this study were laid out differently.  The first had tall Asclepias host plants around the perimeter of the garden and were more isolated in their spacing from one another. This design attracted a higher number of females laying eggs on the taller plants versus the shorter ones.  As quoted from the study, “Host finding and oviposition by monarchs are influenced by species, height, age, developmental stage, and condition of the milkweed in the field (Cohen & Brower 1982, Zalucki & Kitching 1982; Fischer et al. 2015). 

The other design layouts of scattering the Asclepias in the center of the small gardens did not fare as well for attracting monarchs and nor did creating a mixed combination of Asclepias with other plants. Placing taller Asclepias around the border and keeping the plants open and accessible was more beneficial to attracting monarchs.  By doing this it is believed to be helpful for the monarch’s visual perception.  

If you live in the right location and are interested in attracting monarchs to your garden, keep these plant arrangements in mind.  

Photo credit: Teresa Howes, Julesburg, CO.

 Written by CSU Linda Langelo, Horticulture Agent, Golden Plains Area

Thursday, June 18, 2020

Shapes of an indoor herb garden

Posted by: John Stolzle, Jefferson County Extension 

I feel that the positive benefits and entertainment value that come with experimenting and growing plants indoors far outweigh any negatives. An indoor garden can grow 365 days/year, it can provide fresh herbs at a moment’s notice, and can transform (in my case) a drab apartment setting into something a little more lively. Lately I have been experimenting with pruning and pinching indoor Basil with the goal of boosting my plants’ productivity. What I’ve learned is that I have a lot to learn.

Indoor plants will often grow tall and spindly in search of light; pruning can discourage this type of growth and encourage a plant to grow bushier rather than taller (something ideal, imo, in this situation). This type of pruning can be accomplished by pinching off plant growth above a node, the location where leaves and branches attach to a stem. I have been actively removing the smallest leaves and apical, upward most, growth to shape my indoor Basil.

Basil Pruning - past, present, and future?

In the image above: I’ve labeled a node; the red X’s mark where I pinched off new growth at nodes some weeks ago and the plant branched outward; the purple arrows are locations where I might pinch off the plant again in the future.

This method has been very effective in encouraging the plants to branch out. But, I didn’t think about the structure of the plants before I started. I didn’t have an image in mind or an overarching strategy, I just pinched away apical growth here and there. The Basil, growing upwards, hardly able to support itself in the first place, has become quite top heavy due to my interference.

One day, one of the plants fell over (following image). I decided to just leave it, until I needed to use some Basil. Time went by and when I looked again I was surprised to see how the plant had adjusted to its horizontal orientation.

A fallen Basil plant adjusting to its orientation.
The Basil has begun to grow up the spider plant and is now growing rapidly at a node in the middle of the bridge it has made. I’m not sure what to do with this fighter of a plant. I wonder how long the plant will be able to support itself without any extra help, might the stem-bridge collapse under the weight of new growth with time? In an odd sense, I'd feel bad if this plant bridge collapsed, and so I'll probably end up placing some supports below the node; after all, it was my careless shaping that caused this situation. It’s a small thing, but it will be fun to observe overtime, and in the end, I’ll have more Basil to harvest!

I would say, “don’t do exactly what I’ve done”. In the next image you can see that I’ve created a messy jungle of wild Basil growth, because I didn’t start with any idea for cultivating structure and just pinched off growth above nodes! I need to think in more of Bonsai manner.

An untidy tangle of Basil growth.
Second, I often held-off on pinching growth because I didn’t need to use any Basil in my cooking. And now, the upward most growth is too close for my comfort to its light source; it's a problem. But I am still learning, and next time I'll have little better idea for where and how to start.

Final Thoughts:
..And, I will say that I have had luck using a similar strategy with indoor Lavender, but that's a whole different story!
Indoor Lavender
More information on growing Lavender here:

If you are interested in indoor gardening, you may also appreciate these other posts in this indoor blog series: 

Best of luck in your gardening endeavors!