KNOTWEED OR CRABGRASS FOLLOW UP

Nick Christians
May 29, 2012

On March 23, 2012, I put up a blog post about knotweed.  This annual broadleaf germinates very early each season and is often mistaken for crabgrass.

At that time, I posted a picture of an unknown weed that had just emerged at Veenker Memorial golf course in Ames, Iowa that had some of the characteristics of knotweed, but did not look like the other knowtweed germinating on the course at that time.  This patch did look a lot like crabgrass, but it was clearly too early for crabgrass to emerge.  The first picture below is the way that weed appeared on March 23.

I mentioned that I would return later and see what the weed was.  The second picture was taken in late May in the same location on the course.  It is clearly knotweed.  I'm not sure why the newly emerged seedlings looked so much different than the other knowtweed on the course.  You can see why people mistake some knotweed for crabgrass each year.


Photo 1.  Unknown weed on Veenker golf course as it appeared on March 23, 2012.  It had many of the characteristics of crabgrass, but was clearly a broadleaf.

Photo 2.  Picture taken in late May on the same location where the first photo was taken in March.  It is clearly knotweed.

ISU TURF STUDENTS TREAT LAWNS AT REIMAN GARDENS

Nick Christians

May 15, 2012

The turf club has been treating the lawns at Reiman Gardens on Iowa State Campus  for the past several years.  The first two pictures below are from our spring treatments in April.  I stopped out yesterday to see how the turf is doing on the site. We have had a great spring and everything is looking good.

I also got to see the LEGO display at the gardens.  It will be there all summer.  It is quite interesting and worth the time of a visit.

 

UPDATE ON TEES SEEDED OCT. 25, 2011 AND MARCH 12, 2012 IN CHICAGO

Nick Christians
May 10, 2012

Here is a follow up on a post from March 12 about a late seeding of bentgrass on tees in the Chicago area.  My son Tim is a superintendent there at Makray golf club there.  He seeded the tee in the first picture below on Oct. 25, 2011 and covered it.  He had great results and nearly complete cover on March 12 when he pulled off the covers. 

Pictures 2, 3, and 4  below are of new tees seeded on March 12.  All 4 pictures were taken on May 10.  He is planning on opening them May 11 for play.  In a normal year, I tell people that if they get bentgrass seed in my mid-September, they will probably have to wait until early June to open.  If we keep getting these mild winters and warm springs, I may have to change that recommendation.

Picture 1.  Tee seeded on Oct. 25, 2011.

Pictures 2, 3, and 4 were seeded this spring on March 12.  All tees will go into play on May 11.

Artemisia dracunculoides-THE STUMP THE EXPERT WEED.

Nick Christians

May 5, 2012

Here is the latest 'stump the expert' weed.  It was found on the North side of Ames and submitted to our answer-line person, Richard Jauron.  Richard is pretty good at weed identification, but when he has something he doesn't know, he brings it to me.  I can generally get about 90% of them, but when I get something that I cannot identify, I recommend that Richard take it to our local weed scientist, Bob Hartzler.  Bob almost always figures them out.  

Once or twice a year we get one that is so rare that it stumps us all.  That was the case this week with the weed below.  When that happens, we go to the curator of the herbarium in Bessey Hall, Deb Lewis.  Deb hasn't failed us yet on the really rare plants.

This one appears to be False Tarragon (Artemisia dracunculoides) also known as Dragon Wormwood, Dragon Sagwort. and Green Sagewort.  It is similar to the herb Tarragon, but does not have the taste or aroma that makes it desirable for cooking purposes.  The herb commonly used in French cooking is French Tarragon (Artemisia dracunculus), which has a similar appearance.

While it is found in Iowa, it is very rare.  This is the first one that I remember seeing.  We are on the eastern border of where it is commonly found.

Now, how do you kill it?  I would suspect that 2,4-D, MCPP, and Dicamba would not be good for it, but the picture below is from a lawn that had been sprayed with Trimec earlier and was weed free except for this patch and a Canadian Thistle.  I recommended that home owner ask his lawn care specialist to try a pyridine like triclopyr or fluroxypyr, but I'm not sure that these materials will work.  

If anyone has experience in controlling this one, add a comment below.

HOW OFTEN SHOULD I MOW MY LAWN?

Nick Christians
May 3, 2012

Here is a good post from Rod St.John who graduated with his Ph.D. from Iowa State a few years ago.  He is presently working in extension with Kansas State in Kansas City.

 http://www.ksuturf.org/blog/2012/05/how-to-mow-your-yard-rebuttal-of-a-consumer-reports-article/

FOLLOW UP ON MOSS CONTROL

Nick Christians
April 27, 2012

Here is a follow up post from Mark Newton, Supt. of Ames golf and CC.  The last one was on August 3, 2011.  See that blog for more details.

Here is Mark's cultural and chemical protocol from last year.

In the fall of 2010, 1 week after our core aerification (1/2” tines on 2” spacing, 4 inch deep) we started the heavy moss treatments with Quicksilver. These started on September 14^th, and were sprayed every 14 days at the 6.7 oz / acre rate for three consecutive treatments, also included was a spreader sticker and tank buffer to get the PH to 6.5. Also we bumped the fertility way up on the greens, putting 3 sequential applications of 7-7-7 fertilizer at .4 lbs of N per 1000 every 2 weeks, also increased our mowing height to .140 with two rolls per week to help keep green speed. This gave us the most control and reduction in the moss, reducing the population by 40-50% and in some spots completely eliminating them.

In 2011, we are continuing the applications but on a more regular basis with lower rates. The label gives us .4lbs of AI per acre per season. That is 26.8 oz of product per acre in total. To date and future applications are shown below:

- April 6^th 2 oz/acre Complete

- May 10^th 2 oz/acre Complete

- May 24^th 2 oz/acre Complete

- June 17^th 4 oz/acre Complete

- June 27^th 2 oz/acre Complete

- July 11^th 1 oz/acre Complete

- July 25^th 1 oz/acre Complete

- August 7^th 2 oz/acre

- August 21^st 4 oz/acre

- September 6^th Greens Aerification

- September 13^th 6.7 oz / acre + Spreader Sticker

*Note – Greens height in spring start up was .140, lowered to .120 by May 15^th and remained at that height until 2 weeks ago with all this heat back to .130 so I don’t have moss free but dead greens. On a normal year would still be at .120 with 1 heavy roll every Thursday, light topdressing every 3 weeks and 1 verticut / month when weather permits

In this program we also have bumped up our fertility of the greens from prior years, and included more applications of Daconil Ultrex to further aid in the moss treatments. These treatments other than the last one on September 13^th will be put in with our regular spray program of Garys Green Ultra at 9oz/M, Tuff Turf at 4.5 oz/M, PK Plus at 4.5 oz/M, primo at .125 oz/M, and then a rotation of Fungicides. These include, Daconil Ultrex on every treatment (ranging from 5lbs/a to 10), Headway, Banner, Heritage TL, Instrata, and Emerald. Pending on weather a Banol or FORE application might be made.

Additionally for cultural practices we tend to keep greens a little dryer than in previous years with more hand-watering and deep watering. We also make sure that when we do a verticut we are always spraying the next day to not only aid in the recovery and have the best chemical controls, but to decrease the chance of spore transport and giving open areas where it can establish. 

 Here is a picture from June 10, 2010 showing how much moss was on the 18th green

 Here is a picture from yesterday April 26, 2012 on the same area.

One warning from me, it is not unusual for moss control programs to appear to be successful at some times of year, but moss tends to come back.  We'll keep monitoring this site over the next couple of years.  Hopefully Mark has come up with something that really works.

CRABGRASS APRIL 12

Nick Christians
April 12, 2012

We have had three mornings with frost on April 10, 11, and 12. I took a walk on campus on the afternoon of the 12th to see what the impact of the frost had been on the crabgrass that I observed on April 2 (see earlier post). Crabgrass is very susceptible to cold damage, particularly in the seedling stage. I expected the crabgrass to be dead, but to my surprise, it appears to be doing fine. The crabgrass is in a somewhat protected area around the horticulture building, but it is an area that did have some frost.

I am still not seeing much germination of crabgrass in more exposed areas on campus and we have not seen any emergence at the horticulture research station as of April 12. It did get down to 20 F at the research station on the morning of the 11th. If any crabgrass was beginning to peak through, I would expect it to be dead. I'll continue to monitor the early germinating crabgrass over the next few weeks and let you know what is happening.

The trial in which we are applying Baricade and Dimension on April 1, 15 and May 1 to separate plots is continuing. As soon as I have some results from that work, I will put up a post.


Figures 1 and 2. Crabgrass by the horticulture building on the afternoon of April 12 after three mornings with frost.