Monday, October 15, 2018

Fall is for Butterflies, too!

Painted Lady on Okra, Photo Credit: Linda Langelo
Fall is a time when color abounds with the changing season and during that same time there are butterfly migrations.  September is a month where Painted Lady and/or Monarchs can be seen in high numbers.  Unfortunately, there high numbers are diminishing.  According to World Wildlife Fund and the Mexican government due to habitat destruction from illegal logging and tourism in the small patches of forests in Mexico where they overwinter.

If you want to see Painted Lady Butterflies and/or Monarchs and others and help with their population numbers, then think about giving them food sources in your landscape.  Monarch caterpillars require milkweed while the adults take nectar from cosmos, Canada thistle, rabbitbrush, zinnias and many more flowers.
Monarch on aster, Photo Credit Linda Langelo

There are several sites you can go to for information on planting the appropriate plants in your region:

  •   National Wildlife Foundation
  •   Biota of North America's North American Plant
  •   USDA's Plant Database
  •  Colorado State University Fact Sheet on Attracting Butterflies to the Garden
If you are anything like me and want to keep the color in your garden going until the very end of the season, below are a couple of ways to join in and help change the habitat for the benefit of Monarchs, Painted Lady Butterflies and many other pollinating insects:

  • Start a Monarch Watch waystation. You can register your garden.  By doing that you receive a sign advertising your garden's friendliness to monarchs.  Then the name of the city and waystation owner will be listed on the program's website.
  • The North American Butterfly Association has certification program that covers habitat requirements for all butterflies.
  • Wild Ones launched a monarch-specific certification program for gardens planted with species native to North America.
  • The Xerces Society has a certification for "pollinator habitat" program.
All are pollinators need more gardens appropriately developed since cities and even small towns create what is called interrupted spaces.  These are places such as asphalted parking lots and areas expanding with newly constructed developments.  Adding a few key plants to your garden can color up your fall garden and benefit your landscape's ecosystem and attract more color through many fascinating pollinators.

Coloring your garden with key plants can make it a local food bank for butterflies, moths and many more pollinators.  According to Karen Oberhauser, a monarch researcher at University of Minnesota along with other scientists, points out that monarchs "are the flagship species. By preserving monarch habitat that includes nectar sources and milkweed, we're going to be helping a lot of other organisms as well."

Overnight guests on a cotoneaster, Photo Credit: Teresa Howes

Monarchs have a fascinating story.  The Monarchs east of the Rocky Mountains migrate to Mexico to the oyamel fir trees.  The Monarchs west of the Rocky Mountains migrate to Southern California.  Monarchs can not tolerate the freezing temperatures of our climate.  By the end of summer the fourth generation of Monarchs migrate back south starting in October or sooner if the weather turns cold.  They migrate north because of the milkweed necessary for the caterpillar stage of their lifecycle.  This is just a brief summary of their very detailed life.

Fall isn't just for the fascinating colors of leaves, it is for the butterflies, too.  And yes, all the other pollinators, too. 

Monday, October 8, 2018

Colorful Colorado - The science behind our fall colors

by Amy Lentz, Weld County Horticulture Agent

Each year, after the summer season ends and ski season begins, there’s a two to three-week window of color that shifts its way across the state of Colorado. During this short period of time, vibrant colors such as red, orange, yellow and purple will brighten up the sometimes-dreary weather, giving us one last show before winter sets in. I was lucky enough this year to experience the fall colors in early September near Walden, in late September near Frisco, and currently along the lower elevations of the northern Front Range.

This year's predictions for aspen fall color across the state, from

Various hues of yellow, orange and red from Aspen trees near Frisco in September.

As you observe these striking changes in the trees, shrubs and grasses in your surrounding landscape, you might wonder “What is the science behind the beauty?

The genetics of the plant are a key factor in what color they will express during the fall season. Certain trees such as poplar, cottonwood, honeylocust and some ash trees will be various shades of yellow, while others such as maple, sumac and some oaks will lean more toward the orange and red tones.
Yellow fall color of a honeylocust tree.
Environmental conditions are another major factor. As the seasons change and we have shorter day lengths and cooler temperatures, a response is triggered in plants to shift their focus toward going dormant. Not only do these environmental conditions switch on the process of leaves changing color, they can also determine the intensity of fall color from year to year. Along with good soil moisture during the growing season, the warm days and cool nights of autumn help to trap sugars in the leaves, making some fall color displays more vivid.

Brilliant fall color in Jackson County near the Wyoming border in early September.

On a microscopic level, it’s the underlying plant pigments that lead us deeper into the science behind these amazing fall colors. So just how does the leaf make these interesting colors?

During the growing season, leaves have been producing the tree's food using chlorophyll, the dominant leaf pigment that is expressed as a green color. The chemical nature of the chlorophyll molecule allows it to absorb sunlight and use the energy to convert carbon dioxide and water to carbohydrates for the plant. Because the plant is actively growing and needs a large amount of food to be produced, chlorophyll is in high abundance and most of the leaves you see are green. Although other plant pigments are present in the leaves, the large amounts of chlorophyll present during the growing season will mask other, less abundant, pigments.  As the season progresses, the leaves will lose chlorophyll as they senesce, revealing our next pigment…

Carotenoids are also pigments made in the chloroplasts of plant cells, however some carotenoids remain in the cells and are unmasked after the chlorophyll degrades. Because these carotenoids absorb blue wavelengths of light, they tend to show up as leaves with a yellow hue.

Carotenoids expressed as yellow tones on a Kentucky coffee tree. 

The other variations of color that we see in fall foliage comes from yet another plant pigment called anthocyanin. This pigment is actually produced in the leaf of some plants prior to leaf senescence (leaf drop). It’s the combination of the anthocyanin and the carotenoids present that give us the other brilliant fall colors of red, orange, brown and purple. Anthocyanins and chlorophyll can produce brownish colors, while anthocyanins and carotenoids produce orange hues. Those leaves that show a red or purple color have a high proportion of anthocyanins.

Red fall color from anthocyanin production on an Autumn Blaze maple tree.

Red fall color of a burning bush, a common landscape shrub.
So, there you have it...some science behind the beautiful colors of the autumn season that we see not only on trees, but also on woody shrubs and ornamental grasses. These amazing fall colors are another reason we call our state 'Colorful Colorado'!

Monday, October 1, 2018

Planting Fall Bulbs for Spring Color

Posted by: Alison O'Connor, Larimer County Extension

I've always dreamed of having a spring landscape filled with daffodils, crocus and tulips--one that made people drive by slowly, admiring the riot of color. I spent a spring in England during my undergraduate degree and their fields of daffodils were so beautiful...
Thousands of daffodils at a park in London (photo from Flower Magazine)
After a tough summer with countless hailstorms, my gardening motivation has withered. But the thought of starting next year with cheerful and colorful spring bulbs got me excited. So I indulged and bought bulbs. Lots and lots of bulbs. Too many bulbs. I got them home and thought to myself, "Oh no. Now I have to plant these things."
Lots and lots of bulbs to plant. Sigh.
I bought a total of 93 bulbs (allium, hyacinth, daffodils, tulips, crocus). I picked out my bulbs by hand, but if you're planting en masse, then purchasing in bulk is easier and likely cheaper. You can also time bulbs based on bloom period (early, mid or late spring) and color. Confession: I picked out a lot of my bulbs because of their name. For example, I had to buy the hyacinth 'Jan Bos'. Jan is my mom's name and we had a dog named Bosley growing up. Jan Bos!

After such a dry summer, the thought of trying to dig in our soils nearly made me go rest on the couch. But I didn't! And I got those bulbs planted. All of them. And here's how I did it:

Spring bulbs are pretty easy to work with. Essentially, you dig a hole, stick the bulb in, roots side down (pointy end up!), and cover with soil, and water in. Easy peasy. But the type of bulb and the depth at which you plant is important. You're aiming to plant the bulb about 3-4 times the height. So bigger bulbs need deeper holes. Small bulbs are just barely below the surface.
A little comparison of planting depths. Crocus are only 3" below the soil surface; daffodils can be up to 8", depending on the size of the bulb you're planting.
You can decide what bulbs you want to plant together...or have large clumps of the same type. In general, small bulbs will look better if planting in large patches. Large bulbs, like the giant alliums, can stand alone. Hyacinth have wonderful fragrance and the impact is better when in groups. Some bulbs will naturalize and form large clumps over the years (daffodils, squill). You can even plant big bulbs together with small bulbs in the same hole--you just fill in the hole with soil for the correct depths for the bulbs you're planting.
Daffodils just poking their heads out before they are planted.
I planted the bulbs in several areas throughout the front yard. I have planted bulbs in the past, so accidentally sliced a few of the older ones. Oops. But what's fun to see are the new roots that the old bulbs are forming. Check out these crocus:
Crocus that were uprooted during the new bulb plantings. I just tucked them back in.
Following planting, be sure to water in your bulbs and cover with mulch. If you have animals that like to dig up plants, place chicken wire over the top of the planting hole. Consider planting bulbs that are deterrents to animals, like frittilary, allium and snowdrops, among others.
Water in your bulbs and cover with mulch.
The great thing about bulbs is that you kind of forget you planted them and next spring it's a fun surprise to see them bloom! Just knowing the bulbs are there gives my tired fall garden a boost. I'll try to remember to take photos in the spring for you.
(The tired fall garden.)
In the front of this bed I planted 30 crocus and small alliums.
Get out and plant some bulbs--our Front Range Colorado soils tend to stay warm until November, so try to plant by mid-October so that the bulbs can form new roots before the soil freezes. They also need several weeks of cold treatment in order to bloom in the spring. Need more information? Check out the CSU publication on fall planted bulbs. Oh, and should you fertilize? Well, I never fertilize anything in my landscape. The bulb you plant this year should have plenty of "oomph" to bloom next year. If you keep bulbs year-to-year, they will benefit from fertilizer following bloom next year.

The best part about planting was finding this praying mantid...she (he?) was perched on top of my rose, enjoying the beautiful fall day.....and waiting for something to eat.
Hello, world!

Thursday, September 27, 2018

Have You Seen These Non-Native Insects?

Posted by: Jessica Wong, Broomfield County Extension

By now you are probably aware of emerald ash borer and Japanese beetle, two invasive insects that threaten Colorado landscapes. However, these are not the only non-native insects that you should be on the lookout for. 

The Asian mud dauber (Sceliphron curvatum) is a wasp originally from areas in India, Pakistan, Nepal, Tajikistan, and Kazakhstan. It is not a garden or agricultural pest, but all non-native species have the potential to disturb an ecosystem. The distribution of Asian mud dauber in North America currently includes Quebec, Ontario, and now Colorado. Within Colorado sightings have been reported in El Paso, Douglas, Denver, Larimer, Mesa, and Boulder Counties. It is likely that these wasps are in more than just these six counties, which is why we need your help finding them.

A female Asian mud dauber. Photo credit: Whitney Cranshaw
Female Asian mud daubers build nests out of mud along elongate crevices. In the Front Range they have been seen using the edge of windows as nesting sites. They hunt for spiders, which are put into the nests to provision a single larva. Asian mud dauber can be mistake for the closely related black and yellow mud dauber, an insect that is established and found throughout Colorado.    

Asian mud dauber nests in a window frame. Photo credit: Betty Cahill
The next non-native insect you should watch out for is a leafminer of Siberian elms originating from China. The insect is a small moth currently known only by its scientific name, Stigmella multispicata. It has become widespread across the eastern part of North America since it was first found in 2010. It is possible that Stigmella multispicata is already in Colorado.

Leafmines made by Stigmella multispicata larvae. Photo credit: Daniel Gilrein
The larvae of this moth are tiny green caterpillars. These caterpillars create snake-shaped leafmines that get progressively wider as they grow. Once the larvae are fully developed, they exit the leafmine, spin a line of silk and drop to the ground where they will pupate. The leafmine pattern, the size and color of these caterpillars, and their use of silk are characteristics that distinguish this leafminer from the other elm leafmining insects established in Colorado, such as the European elm flea weevil or the elm leafminer.

Stigmella multispicata larvae. Photo credit: Daniel Gilrein
If you see any signs of Asian mud dauber or Stigmella multispicata, take pictures and send them to CSU entomology professor, Whitney Cranshaw, at, and don’t forget to tell him what county you saw the insects. 

Monday, September 17, 2018

Bringing Herbs Indoors for Fall and Winter Use

Posted by:  Mark J. Platten, Teller County Extension Director

Many of us gardeners also love to cook, and all summer we’ve enjoyed cutting fresh herbs to use in our recipes. With summer over and the first frost imminent in the high country, how can we continue to enjoy them? One solution is to buy herbs at the grocery store, although that can be expensive and they may not be fresh. A better solution is to bring our herbs indoors so you can enjoy using them year-round. 
Herb Garden in a Raised Bed
 From every walk of life and corner of the globe, humans and herbs have shared history. Some of the earliest herb gardens have served us with medicinal, religious, and culinary staples; they’ve perfumed bodies, disinfected houses, and repelled insects. Herbs are defined as any plant, or plant parts, valued for “medicinal, savory, or aromatic qualities.” By this definition, herbs can be trees, shrubs, herbaceous perennials, annuals, vines or lower plants.

The best time to bring your herbs inside is before the first frost, which is the middle of September, or earlier, in many of our mountain communities. Perennial herbs such as parsley, sage, tarragon, oregano, mints, lavender, thyme, and chives can be divided in the fall. Use a shovel to cut the plant into sections taking as much root as possible. When dividing, place some back in the garden and pot one or two of the healthiest for your indoor herb garden. Pot the herbs in fresh, commercial potting soil and water them well.

Chocolate Mint
If your herbs are already in pots, check to see if they need re-potting. Fresh soil and enough room for the roots will help them make the transition indoors. Before bringing plants indoors, check each plant for pests by in­specting the stems and leaves. It’s a good idea, once you have them in the house, to keep them away from other plants, just in case they have any insects or eggs you might have missed.

Coming indoors can be traumatic to your herbs. They’ve been used to direct sunlight, rain, wind, and tem­perature variations. Before permanently placing them in your home, first set the plants outdoors, out of direct sunlight, for a few days to get them used to indoor conditions. Then bring them in for a few hours to get them used to the indoors. If you have time, and they’re not in danger of frost, repeat this process for up to a week.

Herbs need at least six hours of direct sunlight each day. A sunny windowsill works great. Turn your herbs regularly so they’ll grow evenly. If you don’t have enough natural light, use an inexpensive fluorescent shop light with a cool fluorescent, or grow, bulb. Hang the light about six inches above the plants and give them several hours of light each day. This lighting method also works great if you’re starting herbs from seed.

You can add to your herb collection by taking cuttings and starting new plants. You can propagate lavender, comfrey, horehound, oregano, peppermint, tarragon, thyme, lemon balm, scented geraniums, sage and rosemary from cuttings. Healthy tip growth makes the best cuttings. When taking cuttings, snip off a 4-5 inch length of stem, remove all but the topmost leaves, and insert into a loose potting soil. Keep the cuttings moist until they become rooted, then transplant to larger containers. Fertilize sparingly and water regularly.
Indoor Herbs courtesy of Andrea Dunn
Herbs can be beautiful indoors and nothing can replace fresh herbs in your home cooking. Imagine an indoor garden of basil, thyme, parsley, sage, rosemary, and chives. So have some fun and save some money by bringing your herbs indoors this fall.

Sources include Colorado Master Gardener Garden Notes:; Penn State Extension: , and Teller County Master Gardener Katie Geist.

Thursday, September 13, 2018

Best plants to create habitat

One of the best reasons to grow native plants is that they do more to provide ecosystem services than non-native plants.  With pollinators and birds in decline, it’s a great way to help. While everyone remembers from basic science classes that plants are at the bottom of the food chain, it is important to realize that some plants pull more weight than others.   For starters, many non-native plants don’t support any insects at all. This is because about 90% of herbivorous insects are specialists to one degree or another.  The insects simply don’t recognize the alien plant as food.

Here is where a functional definition of a native plant can be useful. Entomologist Doug Tallamy (author of Bringing Nature Home) uses this one: is a plant or animal that has evolved in a particular place long enough to be able to establish the specialized relationships that are nature.   Alien plants just have not been around long enough to develop these relationships with the local fauna.
Further research by Tallamy’s lab bear this out; they have found that some oaks have up to 557 species of moths and butterflies, Prunus like wild cherry and plum can yield up to 456 species; and maples support up to 297 species. Introduced species such as Bradford pears have almost no species on them. When it takes over 6,000 caterpillars to raise one brood of chickadees, it is clear which species will help birds  and other insect-eaters the most.

Clearly, the moral of the story is that to support pollinators and birds, plant native plants.  But even within native plants, some species are more helpful than others.  Tallamy’s research has found that just five percent of the local plant genera produces about seventy five percent of the insect food that drives food webs. Including these powerhouse in your garden (even if you otherwise have lilacs and petunias) will do much to support bird species.  And the birds will keep the caterpillars from overrunning your plants. If you have breeding birds in your yard, you won’t see many caterpillars because the birds will have eaten them.

So, how to figure out which species are the powerhouses in our area? A really cool site where you can find native plants for your zip code – ranked by how many caterpillar and moth species they host- can be found at (based on collaborative work with Dr. Tallamy).
Typing in the zip code for Boulder as representative of the Front Range, I get results for both herbaceous plants and trees in order of how many insects they support.  Granted, this website is still in Beta format, and is not perfect, but it is nonetheless a terrific start.

So, the winners of the best habitat plants in the herbaceous category for butterflies and moths for the Front Range are….. drum roll….

Goldenrod (Solidago spp.)
Sunflower (Helianthus spp.)
Strawberry (Fragaria spp.)
Lupine (Lupinus spp.)
Sagebrush (Artemisia spp.)
Violets (Viola spp.)  (We do have native violets, although they are hard to find in nurseries).
Rabbitbrush (Chrysothamnus spp).
Goldenrod lights up the late summer garden and is fantastic for habitat

And in the woody category they are….

Willow (Salix spp.)
Poplars – aspen, cottonwoods (Populus spp).
Prunus (chokecherry, plum) (Prunus spp)
Oak (Quercus spp – esp. Quercus gambelli here)
Pines (Pinus spp)

Chokecherries have fragrant spring flowers and edible fall berries 

You may even have some of them in your yard now, but it couldn't hurt to plant more.

Monday, September 10, 2018

Plant Diseases Have Tartans, Too!

Posted by
Mary Small
State Colorado Master Gardener Coordinator
I went to the Longs Peak Scottish-Irish Festival in Esters Park this past weekend. So colorful! And so many tartan patterns identifying the different clans.
My mind wandered. Instead of thinking about my ancestry, it hit me that clan tartans are similar to some classifications in the plant disease world. Patterns of damage help us identify what “clan” a plant's problem belongs to.

For example, to the left is a picture of lupines. Can you see how some of the plants look  okay and others don’t? The pattern of damage is random – pointing us to the biotic clan. This means that the cause of the damage is probably a living one – like fungi, bacteria or viruses. I think it’s probably a fungal root rot and I would love to look at the roots more closely to help confirm that. But I don’t think digging up plants in this garden would be appreciated, since it’s a public one.

Apple scab on crabapple
Look at the crabapple leaves here on the right. A number of them have scattered spots. You can also see that some of the leaves in the background don’t have spots. The spotted pattern on the two main leaves is not identical, either. This problem is apple scab, which is a fungal disease. An interesting feature of these leaf spots is that they have “feathery”, not solid margins. Apple scab also belongs to the biotic clan.

Fireblight on crabapple
Can you see the random pattern of damage in the  crabapple to the left? Most of the leaves look normal, but there are some scattered twig tips with dead leaves. This is fire blight, which was a huge problem in 2019 largely due to the late spring/early summer rains that helped splash the bacteria around. The disease belongs to the biotic clan.

Leaf scorch on linden
What do you think about the pattern of damage on this linden (right)? All the leaves have the same damage – brown leaf edges and tips. The pattern is uniform on all of the leaves, which points to the abiotic (non-living) clan. The poor tree had two major strikes against it. It was growing in a non- irrigated area (I hesitate to even call it a “lawn”). On top of that, much of its already struggling root system was severed during driveway and street construction. No (or few) roots to absorb water and hydrate the canopy and you get the pictured leaf scorch.  

What happened to this oak (below)? All of the newer leaves (near the twig tip) look dark green and healthy. But all of the older ones are distorted, paler and have some cool-looking fringe at the tips.  The leaf damage was caused by herbicide injury. The older leaves were exposed to herbicide, but the newer ones were not. It’s another member of the abiotic clan.
Herbicide injury to oak
 Next time you’re out and about, see if you can identify which "clan" a plant problem belongs to. By the way, I belong to Clan Ross (tartan below).

The Ross tartan