Localized Drought Stress is Here

As stated in an early post, summer stress is developing throughout the state. Summer stress isn’t widespread or severe but it is developing, particularly wilt stress, within very localized areas of many landscapes. Landscapes that receive little to no irrigation are especially prone to wilt and drought stress right now.

It is important to scout and assess the severity of any wilt stress in moderate-to-high value areas of the landscape. Hours are important, don’t put off the scouting of wilt stress. Assuming the grass or other plants will tolerate wilt stress without confirming the severity of the situation can lead to severe drought stress and stand loss at this time of year.

Symptoms of subtle wilt stress on June 22. Healthy turf will likely to tolerate this level of wilt stress.

Symptoms of subtle wilt stress on June 22. Healthy turf will likely to tolerate this level of wilt stress.

 

 

 

 

 

 

Grasses such as the fine fescues and annual bluegrass will be [Read more…]

Drought Ends in New Jersey

Last autumn I was blogging about the drought conditions that we were experiencing. Thankfully, this winter’s precipitation, albeit lots of snow, has changed our water status in the region. The U.S. Drought Monitor no longer lists New Jersey as having abnormally dry or moderate drought. You can view more details at http://www.nrcc.cornell.edu/page_drought.html

Expect I will have to post about snow mold disease and flooding, once we get a thaw.

The current drought monitor map of the Northeast.

The current drought monitor map of the Northeast.

Abnormally Dry to Moderate Drought Condition in Much of NJ

I mentioned in my previous post that dormancy has been apparent in many non-irrigated turfs. These conditions still persist throughout the central and northern NJ.

You can view the distribution and severity of the dry conditions throughout the northeastern U.S. at http://www.nrcc.cornell.edu/page_drought.htmlThis map shows that southern NJ is not experiencing drought conditions; whereas, central NJ is experiencing abnormally dry conditions, and northern NJ is experiencing moderate drought. This dryness typically doesn’t last through winter but it is something to watch. Moreover, you should assess your landscapes for any potential susceptibility to winter desiccation.

I want to share a some observations and ideas that have  come up while discussing this topic with turf managers.

  1. In those areas experiencing limited rain this fall, there has been very little recovery from summer stresses on non-irrigated turfs (and other plantings). These turfs may benefit from an application of a slow release N source to ensure recovery starts when water levels improve in late winter and early spring. Recall that NJ prohibits N applications to turf by professionals after December 1st (except on golf courses).
  2. While dry soil conditions this fall may have induced dormancy of the grass, the grass may be vulnerable to extended dryness through the winter especially in localized areas of turf that are sloped (water runs off) and exposed. These dry areas could experience desiccation damage if there are cold harsh winds combined with little to no snow or rain. If feasible, some irrigation of these areas before winter sets-in may be helpful in avoiding winter damage.
  3. Localized dry areas may have developed water repellency (become hydrophobic). These areas could benefit from an application of wetting agents to improve infiltration of rain and snow melt into the soil. Even if the soil is not hydrophobic, wetting agents will improve water infiltration of irrigation or winter precipitation.

Let’s hope that precipitation becomes more typical where it is currently dry.

Have a Happy Thanksgiving!

Dormancy in October? It is very dry and cool.

I spent a couple days this past week teaching in a turf care training program at Central Park in NYC. Many lawn areas in Central Park that are not irrigated were entering dormancy because of the dry soil conditions. And as you look around there is an increasing acreage of turf as well as shrubs and trees in our area that are being challenged by drying soil conditions. Fortunately, it is cool and many plants are tolerating the drying by entering dormant.

Lawn area entering the onset of dormancy. Shoot growth is shutting down and leaves are wilting.

However, managers should think about their end of the season programs related to irrigation shut down [Read more…]

“Rain Shadows”

Many people are aware that tree root competition is part of the challenge of maintaining turf within the drip line of trees. But the canopy of trees also contributes to the challenge by capturing and retaining much, and in some cases all, of a rain.

Rain shadows have been evident for some time now but the damage from the soil dryness has reached moderate to severe levels over the last couple weeks. Many of the lighter rainfalls over the last month haven’t wet the grass let alone the soil under large trees at Hort Farm No. 2 in North Brunswick.

The cumulative effects of a "rain shadow" and tree root competition lead to drought stress under trees.

Dormancy vs Death

The question of the day is… How do I know whether the grass that is losing its green color is going dormant or going to die? It isn’t always easy to tell but here are some clues that can help.

First, asses the uniformity of the grass. Is all of the grass turning brown or straw colored? Or… is the grass turning brown in spots or small patches? If the browning is occurring in spots or small patches, there is a good chance the grass plants in those spots are dying, especially if this occurs in a matter of hours to a couple days. [Read more…]