“Trees: the good, the bad and the ugly” presentation in Shoreview this week

With spring’s arrival many area green thumbs are anxious to get out and start prepping gardens for the much-awaited growing season. Metro lawns are sill blanketed in snow and it seems as though spring will arrive a bit later than it has in recent years (2010 being an exception).

But, Minnesotans know that weather in our state can change overnight and the transition from the lingering cold into warmer, spring-like conditions is inevitable.

Planting flowers, vegetables and herbs is likely to be a couple of months away, but the prime time for tree planting is just a few weeks out.  

“The best time to plant trees in our area is from mid-April through early June and again in late fall,” Senior Manager of Wildlife for the Three Rivers Park District John Moriarty said.  “Summer’s heat can put too much stress on young trees.”

Moriarty will be speaking all about trees in his presentation “Trees: The Good, Bad and the Ugly” at the Shoreview City Council Chambers on Wednesday, March 20 at 7 p.m.

His presentation is the third in a four part series hosted by the Shoreview Environmental Quality Committee (EQC) in its Environmental Speaker Series: “Our Neighborhoods, Our Environment.”

Jessica Schaum, environmental officer for the city of Shoreview said the EQC has long looked at Moriarty as an expert on native trees and plants, as well as invasive species. Prior to his current position with the Three Rivers Park District, Moriarty was the natural resources manager for Ramsey County for 14 years.

“He’s very knowledgeable on these topics and is a good story teller,” Schaum said. “I’m sure he will use some humor in his presentation as well.”

Moriarty will speak about a number of tree related topics, including how to control invasive species, such as Siberian elm, amur and Norway maples and buckthorn. He will also talk about ways to protect trees like green ash and American elms, which are particularly disease-prone.

Ramsey County’s efforts in removing invasive plant species and in planting native species will be discussed, as well as which types of trees are best for landscaping.  

Many people like to plant trees that are fast growing and produce a lot of flowers, such as the previously mentioned maple and elm varieties. The problem is these trees produce a lot of seeds, which are wind-swept into woodlands. In forests and parklands these prolific growers more-or-less take over, crowding out native species, Moriarty explains.

He said good alternatives to trees like amur and Norway maples and Siberian elm are bur oak, sugar maple, basswood and hackberry trees.

Gertens Greenhouses and Garden Center’s Nursery Manager Robin Ostrander said each tree choice should be based on location, soil conditions and the purpose of the tree. Certain trees are more ornamental than others and some provide more shade, for example.

“People in the Twin Cities are planting a lot of maples, because they are sturdy trees with nice color that do not mind an urban environment and they are relatively fast growing,” she said.

Ostrander said they used to plant a lot of silver maples at Gertens, but no longer do because of the invasiveness of the trees caused by their seeds. 

She said in recent years “Freeman” hybrid trees like autumn blaze have become popular in the area.

“As far as maples, I really like the sienna glen because it’s a hybrid first found growing locally in the Lake Elmo area that mother nature made herself,” Ostrander said.

Changing growing zones

According to Moriarty not all non-native species are bad. He said that traditional growing zones are changing along with the climate.

The U.S. Department of Agriculture’s most recent Plant Hardiness Zone map from 2012 shows these changes.

According to the map, areas of the state stretching from the Twin Cites metro and south are now rated as a hardiness zone 4b, and a small section of the state in extreme south-central Minnesota is now rated as a zone 5a.

What this means is trees like the shagbark hickory, ginkgo (native to China) and the red bud, which in the past have grown farther south, are now becoming popular around the Twin Cities, Moriarty said.

Conversely some coniferous trees like balsam firs and certain species of spruce are no longer growing well around the southern part of the state, because of increasing summertime temperatures. 

Regardless of the tree type or time of year they are planted, regular watering is still always key to keeping trees alive, Moriarty said.

Ostrander added that it is crucial to find balance in watering, because you do not want to over or underwater trees.

Too much water will basically drown a tree and rot its roots and too little will starve it of much needed moisture.

“When I water trees I water them thoroughly and wait a few days until the soil dries out a bit before watering again. The amount of watering will depend on the tree and soil conditions where it is planted,” Ostrander said.  

Moriarty’s presentation on trees is free and open to the public. He will dedicate time to answering tree-related questions attendees may have.

Joshua Nielsen can be reached at jnielsen@lillienews.com or 651-748-7824.

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