White Birch Borers

[JoanneH]

I have some concerns about a very old cluster of beautiful White Birch trees we acquired with our new old home purchase last year. I had them treated with a systemic pesticide (injected around the root zone). They are very large, and appear fairly healthy, with some minor die-back of small branches that drop off from time to time.
I'm not keen on using a lot of pesticides, and research has told me that the southern exposure and sandy soil of our zone 6 shoreline location are not the best for birch.
Should I think about establishing a similar sized group of another type of tree nearby to provide light shade for our patio, in anticipation of losing these trees eventually? Or continue to treat annually? It would be a shame to lose them, but I wonder if it promises to be an uphill, expensive, and toxic battle?
Also, any suggestions for good replacements or additions to the planting for dappled high shade?
Thanks for help/advice/moral support.

 

[jimmyq]

your subject lists birch borers but you dont mention them in the text, did you have problems with them? If you want to plant a new set of trees to replace the birch can you give a bit more info on the planting location and site details?

 

[Kneejerk Bombas]

It will help to improve the soil with top dressings of compost and organic mulch. If you have lawn in the area around the tree, carefully get rid of it. Planting under story perennials and shrubs can aslo help by shading the root zone, as long as the plants chosen are not very aggressive as to end up competing with the Birch for water and nutrients.
Try to improve the growing conditions and you may find you can reduce or eliminate the need for chemicals.

 

[JoanneH]

Paul, about the borers, I haven't inspected the tree closely for signs, will do that today after researching yesterday, but the guy I had out from Bartlett Tree to treat the Hemlocks for adelgid recommended the borer treatment, and I think the previous owners had been doing it. There are several small dead branches scattered throughout the crown, and they drop off occasionally, but mostly I've relied on the expert. I do find them a bit saw-and-chemical-happy.

The area is in the Southwest corner of the patio, early shade from a huge sugar maple just Southeast of the birches, then full sun. Zone 6, good topsoil but sandy further down (I'm at the mouth of the CT River where it meets LI Sound). Fairly well-drained soil, but I think the water-table must be fairly high because we use a nearby shallow well for water supply. The well and the surrounding protected salt-marshes and river make me even more chemical-averse. Could use a bit more light shade even if the birches are OK.

Mike, nice x-ray. I guess I'm already on the right track, have been mulching (got a new wood-chipper, yay!) and planting broadleaf evergreens for some privacy in the area. How far out should I mulch? Drip-line?

Thanks.

 

[Jay Banks]

Joanne,
When looking for replacement trees look at natives such as shadblow (serviceberry).

Here's a UCONN site for you to look through for choices
http://www.hort.uconn.edu/plants/

GO HUSKIES.

 

[underwor]

I agree with Mike, make the environment as close to that in the woods as possible, keep the roots mulched, cool and well watered and borers are rarely a problem. Also, white birch is very good about sending up replacement trees from the base on its own. Let a couple of these get started and if the old trunks die some day, the replacements will be there.

Good Luck, bob

 

[John Paul Sanborn]

If they are doing a soil injection of Merit, I would not be to against that. But if they want to do a trunk injection, then you are harming the tree to save it and need to do it nearly every year. The treatment can then kill the tree.

As Mike and bob say modifying the root plate area is the best cultural practice to keep white barked birches birch healthy. The only big ones I've seen have some sort of shade from the south. Studies in the Madison, WI area show that trees on the north face of a hill always do much better then those on the south. East is better then west, since the soil has less time to warm up.

Secons would be regular deep irrigation, I use a Ross Root Feeder on mine.