CO-Horts Blog

Monday, May 25, 2015

A great Colorado botanist most of us have never heard of - by Irene Shonle

Many of the early botanists in Colorado are familiar to people, if only because their names are memorialized on mountain peaks and with specific epithets:  the twin fourteeners Grays and Torreys  (named after Asa Gray and John Torrey of Flora of North America fame), or Townsendia hookeri (named after William Hooker), Primula parryi (named after Charles Parry), and on and on…  for an interesting read on these famous explorers and botanists, go here:

But, when I recently came across a book about Hazel Schmoll, a Colorado botanist who did much to protect our state flower, I was chagrined to realize I had never heard of her.  Here is a little bit about what I learned:

  • She was determined and took schooling much further than most women in her era. She graduated from CU in 1913 with a degree in biology, then earned a master's degree in botany at the University of Chicago.   Even more unusual, she went back and became the first woman at University of Chicago to obtain a doctorate degree in ecological botany (the at-the-time new science of studying plants in their natural environment).  A woman after my own heart (since I also have a doctorate from there in Ecology and Evolution). Further evidence of her rebellion against the limitations put on women were in evidence in her dress (she refused to use a sidesaddle but shockingly wore a split skirt and often even pants) and that she chose to never marry.  She also worked bring the right to vote to the Eastern States while she was teaching at Vassar  - she did not like not being allowed to vote out there after being allowed to vote in Colorado (Colorado was the second state to allow women to vote in 1893).
  •  From 1919 to 1935, Hazel Schmoll was Colorado's State Botanist at the Colorado State Museum.  When the museum closed the thousands of herbarium sheets she had worked on went to CSU and CU, and are still used today.  At the time, there were still quite a few men in opposition to a female State Botanist, and this was discouraging, but her struggles and excellent work paid off since she won the respect of many.
    Hazel Schmoll is shown in 1924, when she worked in the Colorado State Museum as state botanist. (Carnegie Branch Library for Local History, Boulder Historical Society collection /Courtesy photo)
  •  While conducting a plant survey at Mesa Verde National Park, she discovered Astragalous schmollae, a rare plant now named in her honor.
  •  In that early era, people would head for the hills to pick armloads of wildflowers (for example, in 1911, a single trainload of people picked over 25,000 columbines in one day in Silverton). Hazel noted that the populations were diminishing, and that our state flower was in danger (it was voted as state flower in 1899).  Hazel led the effort of the Colorado Mountain Club, and in 1925, she helped pass the "Columbine Bill" which still protects our state flower.
  •   She lived until she was 99!
I wonder how many would be left in the wild today without the Columbine Bill?

So, next time you see a meadow full of Columbine, give a nod of gratitude to Hazel Schmoll, an underappreciated botanical treasure!

Wednesday, May 20, 2015

Does your Bluegrass have the Yellows?

Lush, water- and fertilizer-fueled grass growth is often
light green or yellow. Clippings should be collected if
you can't mow often enough to prevent the accumulation
of clumps - which cause the grass underneath to turn
even brighter yellow!

Tony Koski, Extension Turf Specialist

You’re not the only one who has had enough! Have you noticed some yellowing in lawns in the past week or so? The precipitation and cool weather over the past couple of weeks have created some temporary (well, if the rain stops) problems for our cool-season lawns.

While there is plenty of glowing green turf out there, the persistent moisture has encouraged ample growth, especially on well-fertilized lawns - growth which may be lighter green or even yellow. Fast- growing grass leaves are often lighter green because leaf chlorophyll content is less concentrated or “diluted” by the rapid growth rate. Plus, those leaves lower in the canopy are normally more pale green – or even slightly yellow – than leaves higher up in the canopy, where light intensity is greater. When weather delays mowing and the grass gets tall, the darkest green leaves are mowed off – leaving the pale green and yellow leaves behind. When this rain stops, temperatures warm and you catch up on your mowing, growth will slow and more normal color will return.

Iron chlorosis develops in random patches. The youngest leaves
will be the brightest yellow, since iron doesn't move well
from older leaves to younger ones. Rapid growth and saturated
soil will encourage this temporary iron deficiency in turf.
The wet, cool conditions are also causing iron chlorosis to develop. The roots can’t get adequate iron from the soil to supply the rapidly growing shoots – so the turf becomes iron-deficient and chlorotic (yellow). With iron chlorosis, the YOUNGEST, newest leaves at the top of the grass plant will become deficient first. This is in contrast to the yellowing described above, which occurs on the OLDER leaves in the lower part of the turf canopy, with the youngest leaves at the top of the canopy being darker green. Persistent, severe iron chlorosis can cause the entire plant to become yellow – sometimes to the point that some plants die and the turf thins out. As soil temperatures warm and we get drier weather, the iron chlorosis we are seeing will diminish. 

Melting out disease can become a big problem in bluegrass
lawns during extended rainy, cool periods in the spring.
Melting out can quickly kill large patches of turf when
conditions are favorable: cool, moist and cloudy.
We are seeing melting out (Bipolaris sorokiniana) in bluegrass lawns now. Normally more of a problem in the Midwest and other wetter parts of the country, this fungus is turned on by continuous cool, wet conditions.  It causes small brown spots to form on leaves (similar to leaf spot disease seen on turf under warmer summer conditions – but those are caused by a different fungus, Drechslera poae) and leaf sheaths. Under ideal (cool, wet) conditions, the fungus invades crowns, rhizomes and roots of the grass plant – causing leaves to turn light green or yellow. Heavily infected plants die and turn brown. The turf yellows and thins out in patches – hence the name “melting out”. Severe melting out can cause large, irregularly shaped patches of dead turf. Advanced melting out is very difficult to control with fungicides. This disease is more common on older lawns; overseeding with newer, more resistant bluegrass cultivars is probably the most effective management tool. Also, heavy spring nitrogen use will increase the potential for and severity of this disease.

Roughstalk bluegrass (Poa trivialis) loves cool, rainy weather.
Rainy, cool weather also encourages the growth of two light green grasses in lawns: annual bluegrass (Poa annua) and roughstalk bluegrass (Poa trivialis). Poa annua is flowering profusely right now (an important allergen for many this time of the year), and Poa triv will spread rampantly in this kind of weather. Selective control of Poa trivialis in bluegrass lawns is not  possible; annual bluegrass can be controlled long term using a combination of strict cultural practices and use of Tenacity (mesotrione) herbicide.

Annual bluegrass (Poa annua) invasion is favored by cool,
rainy weather.
When things dry out and warm up, the severity of these problems should diminish – except that the Poas will never go away on their own. And I’m betting that this will be a banner year for necrotic ring spot – a root rot disease that is encouraged by overly moist soil conditions in the spring and summer. More to come on that…

And speaking of more to come….a look at the 10-day forecasts by both AccuWeather and Weather Underground are calling for rain on 9 of the next 10 days in Fort Collins.

Friday, May 15, 2015

Totally Tuber: Planting dahlias in your garden

Posted by: Alison O'Connor, Larimer County Extension

I'm stepping up my game this year at the Larimer County Fair. I've entered nearly every year since I started working for Extension and love the competition, the judges' remarks and the sheer chaos of entry day. But I've never entered much in the Open Class Flower Show, primarily because I don't feel my flowers are worthy. Insect damage, bleached petals and misshapen foliage does not make the cut in our judge's eyes. Plus, there are really, really good flower growers and they actually know what they're doing.

But this year I bought dahlias. I grew a few several years ago and they were surprisingly easy, low-maintenance plants. But I had tucked them in a bed on the side of the house and didn't enjoy them much. Then I got an email from an Oregon dahlia company..."Sale! 50% off! Buy dahlias now!" So I did.

For those who haven't attempted the "summer-blooming bulbs", here's a quick lesson in planting dahlias. Don't be scared--they're really no different than a daffodil or tulip. Yes, they do need to be dug from the ground in fall (they are not winter hardy in Colorado), but properly stored and cared for, dahlias (and their folk) can last for years.

I purchased a mix of flowers from the "Cut Flower Collection" and also a group from the "Itsy Bitsy Collection". I figure that by the time the Fair rolls around, I should have enough flowers to scrape together an arrangement. And the names are the best part! Some of my cultivars include 'Bride to Be', 'Lights Out', 'Bambino' and 'Angels of 7A'.
Each tuber comes stamped with the variety name.
First of all, read the instructions sent by the grower. They know what they're doing and what's best for their plants. One of my favorite things about dahlias is that they don't need to be watered following planting--only after sprouts appear above the soil surface.
Planting instructions attached to the dahlias.
Carefully inspect your tubers and make sure they are firm without any signs of rot. If they have sprouted, you can snip back the new growth to a length of one inch. This will not hurt the dahlias and will actually encourage better growth.
Cut back new growth to 1" in length.
I have a sunny location in my garden where all the plants died over the winter (except for the silver lace vine, which nothing can kill). A perfect location for the dahlias. I raked back the mulch, squealed at the amount of worms I found and started digging. Dahlias need to be planted flat on their side 6" deep and 18-24" apart. The plants can get quite large at maturity (anywhere from 12" to 5+ feet; taller plants will need staking) so proper spacing is necessary.
Pulling back the mulch to expose the soil.
Plant dahlias flat on their side in a 6" deep hole. Space tubers 18-24" apart.
Digging each hole was getting cumbersome, so I stepped up production and dug a trench and placed the tubers, properly spaced, in the trench.
The dahlias are planted and ready to cover with soil.
Now, because I always forget where I plant my bulbs, I decided to mark where they were planted with a golf tee. (Of which I have many on hand.)
Handy dandy golf tees to mark where the tubers were planted.

We have a new addition to our household, Maple. She is a rescued research beagle from Colorado State University and she is ALL PUPPY. Curious about everything and learns something new about the world every day. I didn't realize she would have such an interest in the dahlia tubers. I should have known. Now I'm worried that she may be inclined to dig them up, so I bought some fencing.
Maple meeting a tuber for the first time.
I covered all the tubers with soil, added mulch (in a thin layer) across the planting areas and marked each one with a golf tee. Now I just have to wait a few weeks for growth. Let's hope it stops raining.

And if you don't have garden space, dahlias can easily be grown in containers. Just follow the same spacing and depth requirements mentioned above. Also consider the mature size of the plant and your container size--ensure it's big enough to support the plant at maturity (generally a 12" by 12" container will be large enough). Cover the tuber with a few inches of soil and water it in. Be careful about watering until growth starts...but don't let the potting media dry out. Also make sure your media is well drained so the tubers don't rot. You'll also need to fertilize throughout the summer.

Dahlias are great container flowers. Just make sure your container is large enough to support the plant when full grown.
Later this fall, I'll be sure to post about what to do to harvest and keep your dahlias for next year. I'm sure Maple will be a great helper. For the official CSU Extension Fact Sheet on summer-blooming bulbs, click here.
Maple requested the pansies.
I'll remove them as the weather gets too hot and just allow the dahlia to grow.

Wednesday, May 13, 2015

Western Spruce Budworm Outbreak Potential

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

The western spruce budworm (WSBW), Choristoneura occidentalis Freeman, is the most widely distributed and destructive forest defoliator in western North America.  An outbreak has been prevalent throughout Teller and several adjacent counties the past three-to-four years and is likely to continue into 2015.  Their primary host is the Douglas-fir, although they will also be found on white fir, Engelmann spruce, blue spruce, and subalpine fir. 

The budworm larvae emerge from their hibernacula in early May through late June and begin feeding on old needles until the new buds emerge and then they feed on the new growth, hence their name.  They emerge as tiny larvae, approximately 1/8-1/4 inch, with yellowish-green bodies and a brown head. 
Juvenile Larvae
As the new needles continue to lengthen, the rapidly developing larvae continue to feed.  It is during this phase that most of the damage occurs when they loosely web the new foliage together, feeding in relative protection from predators.  You may not even notice them until they drop, or hang, from the affected trees, attached by what appears to be spider-like threads. 

Webbing of New Tips

They go through six stages of growth with the final larvae between 1-1.25 inches in length, with tan or light-brown heads, and brownish-olive bodies.  Each mature body segment has two conspicuous pairs of white spots. 

Mature Larvae

This process of growth takes approximately 40 days, at which time the larvae pupates and the adult moths emerge 7-10 days later. 

Pupal Casing

Some of the first moths emerged last year in Teller County the middle of July.  

Western Spruce Budworm Moth

After mating, the females lay masses of overlapping, green eggs on the undersides of host tree needles.  The young larvae hatch in approximately 10 days and move to crevices under bark scales, or lichen, where they spin silken hibernacula and overwinter.  This completes their cycle, with one generation per year. 
The greatest impact to mature trees is reduced growth because new needles photosynthesize more efficiently than mature needles.  Multiple years of defoliation can lead to branch tip loss, top death, and even tree mortality.  Saplings and young stands directly beneath the mature host trees are especially affected when the larvae disperse from above.

Tip Defoliation

Even if the WSBW doesn’t kill your trees, the injury and stress will make your trees more susceptible to secondary infestations of Douglas-fir beetles and other insects/diseases, which may lead to the death of your trees. 

In most years, the natural predation via arachnids, parasites, climate, and birds will keep them in check.  Adverse weather conditions, especially sudden freezes toward the end of May when the larvae have just emerged, could kill a significant portion of the larvae.  Unfortunately, with our relatively mild winters over the past decade, this may not be likely.  With three plus years of fairly heavy outbreaks in the area, you may want to consider other measures.

Cultural practices such as thinning, watering, and fertilizing enhance tree vigor, which may help them withstand repeated attacks.  Chemical control is often used to protect high-value trees, much the same way as we protect against mountain pine beetles.  For more information on chemical use, please see Washington State University Extension’s Forest Health Note:  One successful control agent is a naturally-occurring bacteria, Bacillus thuringiensis, or B.t.  It is specific to larvae without having any adverse effects on the environment.  See the CSU Extension Fact Sheet for more information on B.t.

It is often cost prohibitive to spray your entire property, especially if you have large parcels of land; although, there are several subdivisions in the region that have conducted aerial spraying.  There tends to be a minimum number of acres required by the aerial operators.  In Teller County, it is 450 acres minimum with a cost around $55 per acre.   

Even with aerial spraying, only the top of the canopy is covered. Between spraying and predation, hopefully the outbreak can be put in check and most of the trees saved.  Whether conducting individual or aerial control, the best time to spray is the two-to-three weeks following bud break, generally occurring early, to mid, June.
For a list of forest contractors who may be qualified to spray your individual trees, please contact your local Extension office, or the Colorado State Forest Service