Those yellow ash trees

Green ash overhanging a road at Farm Island, Pierre.

We are at, or maybe just a few days past, the peak colors for green ash in our area. Hopefully when this is published some of the yellow will still be on the trees.

There’s an invasive pest to the green ash, the emerald ash borer, that if left uncontrolled will kill any tree it infests.

If you don’t know how to identify an ash, the vast majority of all yellow trees at this time are ash. So take a drive around town and imagine what each street will look like if every yellow tree is removed. This will result in somewhat sobering images, but ones that are pretty much guaranteed – backed up by the fact that odds makers in Vegas aren’t running a line on a probability the borer will get to Pierre (I checked).

The borer has been found in the state but so far has yet to be detected outside of Sioux Falls and Canton. Unfortunately all evidence says the borer will get to the Pierre / Fort Pierre area in a decade or less. This time schedule is estimated on how quickly the borer colonized new areas in other states. The ash borer is a notoriously weak flier, preferring to stay on a host tree until it completely dies, then moving onto a nearby neighbor. Further, the borers do not like to fly when the wind speed is above 5 mph, so when the adults are active and strong winds are coming from the south east, the borers are likely to just stay on their host trees instead of being blown towards us from the Sioux Falls area.

But the human factor can easily change things, and in all likelihood the borer will arrive in our area hitching a ride on a vehicle or in a chunk of firewood.

So back to that driving trip around town imagining the yellow trees are gone. Options are to treat or cut down. Treatments are best done by a professional using restricted use insecticides, injecting each tree every other year, to the tune of $200 per tree. For some, the annual expense of $100 per tree is the right decision given the size, accessibility, economic, and emotional values of the trees by the home owners. If not, well, the tree must be cut down. No exceptions.

So consider your landscape as it sits now. Ask yourself, do you have any ash. If so, how many and do you want to keep one, more, or none. Removing individual trees over the course of several years is usually more palatable both in cost and aesthetics compared to the removal of many trees all at once. Another good question to ask yourself is what is your intended plan for the house five to 10 years from now — will the house still be yours or is the plan to sell? Mature trees add value to homes but ones which must be cut down soon perhaps do not.

The one advantage we do have over the borer is time. Please use it wisely.

Art Smith is a co-owner of East Pierre Landscape and Garden Center, 5400 SD Hwy 34, Pierre.

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