NDSU Extension - Williams County


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Poplars Not Popular - Be Watchful of Alfalfa

Published May 8, 2013
Poplars Not Popular - Be Watchful of Alfalfa

Trees and Shrubs for Northern Great Plains Landscapes

Poplars Not Popular

Spring is here and new homeowners are very enthused about beautifying their new home with trees, shrubs and a lawn. Developing a home landscape plan can be fun but requires a lot of hard labor and patience as plants, especially trees, grow to maturity.  When it comes to trees for new home yards and farmsteads we tend to prefer those that grow fast. Years ago, we looked to the Siberian Elm to fulfill growth expectations. Many were planted in field shelterbelts, around farmsteads and homes. It took about 20 years to realize this tree does not live very long. Although it has some drought tolerance, its life span is reduced when little moisture is received. Those who planted this tree also found it was susceptible to attacks of certain insects and very susceptible to phenoxy herbicides like 2,4-D and canker.  After we learned Siberian Elm was not the tree we thought it should be, we turned to the hybrid poplars for that fast growth. Indeed, it did grow very well for about 10 years but we learned most will be dead before they reach 20 years of age. Upon moving to our new home 20+ years ago, we hand planted many northwest poplar trees, occasionally giving them supplemental water.  As the trees approached 15-20 feet their leaves began to turn color and drop pre-maturely. By late August many were devoid of leaves. Attempts were made to provide water but we could not keep up. Today, just a few remain but they too are struggling. By the end of this summer I expect only two of the original 24 trees will be around to experience next winter.  Besides the high water requirement, hybrid poplars are often attacked by gall mites, cytospora canker, stem decay, and wetwood.  When folds ask for my thoughts or suggestions on fast growing trees, hybrid poplars usually become part of the discussion. Obviously they are not popular with me. However, they do have a place in situations where other longer-living trees that have lower water requirements can be planted nearby and the property owner is prepared to remove the declining poplars as they reach 10-20 years of age.  The Extension Service of North Dakota State University has published a neat handbook “Trees and Shrubs for Northern Great Plains Landscapes”. It contains pictures, descriptions, etc. of the major species of trees and shrubs to consider for planting in the Northern Great Plains. Although it is not intended to be an all-inclusive text, the publication includes information on 102 species plus cultivars and varieties. Hard copies can be purchased at the office now located at 302 East Broadway, known as Broadway Commons. Cost of the publication is $10.

Be Watchful of Alfalfa

Last spring many alfalfa fields were hit hard by alfalfa weevils which severely reduced yields. No one knows if they will be a menace this year. However, we do know they will actively feed when there are 430 to 595 degree days (DD) using a base of 48° F.  With this spring being so cold, the growing degree threshold will be later than normal. It is recommended to begin looking (scouting) around 300 DD. As of May 7, the North Dakota Agriculture Weather Networks (NDAWN) calculated 62-67 DD for the Sidney/Williston area. In the Tioga region, there were only 24 DD. Growing degree days are calculated by subtracting the base temperature (48° F) from the daily average of the high and low temperature. So, a day with a high temperature of 76° F and a low of 46° F would have 13 DD (76+46=122/2=61-48=13).  It will be a while before we reach 300 DD. It is possible we could reach this level by June 1. The accumulated degree days can be monitored at the NDAWN website: http://ndawn.ndsu.nodak.edu/index.html. There is also a link to NDAWN on our website. Go to applications, then insect degree days, then to maps. Be sure to select base temperature of 48° F.  Alfalfa weevils can wipe out a field of alfalfa in just a short period. So, it is important to scout the field and be ready to apply an insecticide well before damage is seen from the road.

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