Wild Ones 2002 Archive

QUESTION #11: Toxic spruce needles

I read that spruce needles are toxic. Does anyone know if that is only for
emerging seedlings or also for existing vegetation, like shrubs? Anyone have
any experience with it? Does anyone know where I could find out? We recently
had to cut down 50 large spruce trees and are putting them through a chipper.
That means I have LOTS of wood chips with spruce needles and want to make as
much use of them as I can. Thanks.

-- Phyllis of Marshfield, WI

RESPONSES:

7-16-02

Don't know if this will be helpful or not. I am a Wild Ones member who also
happens to be a forester. Have never heard of spruce needles being "toxic".
Most coniferous leaves, ("needles"), however, are fairly acid. For example,
I believe using pine needles as mulch, over time, could raise soil acidity in
a garden. I don't think that using wood chips that have needles mixed in would
be a problem in pathways, but you might want to be careful about using them in
gardens full of plants that won't tolerate acidic soil conditions.

-- Lauri of Carlshend, MI

7-8-02

Spruce needles are not toxic as far as I know but are acidic. Anytime a great
deal of spruce or other evergreen material is incorporated into an area the pH
will drop. This can effect plants adversely.

-- Jewel, Wetlands Nursery, Saginaw, MI


7-6-02

I have a wonderful old blue spruce and I needed to prune it up about 12 feet.
It drops many needles and I cherish them for a mulch. I have planted several
rhododendrons, giant hostas, and even have a small nursery of sapling spruce,
junipers and oaks in 2 gal containers that I have put in a raised bed and sunk
the containers. Note from WO Hostess: Rhododendrons are not native in all
areas of North America. Hostas are not native.

The mulch is more acidic than toxic. It has enhanced the growth of the saplings,
shrubs and forbs. Rhododendrons prefer acidic soils and the pine needles provide
this essential element.

The forbs and grasses which are planted on the outskirts are big blue, Indian,
purple cone, with some clasping cone(yellow cone). These grasses and forbs do
receive more sun than the rhododendrons. Little blue is planted along the border
and it loves the dryer micro climate.

Pine needle mulch is a nice benefit to have when used under the proper conditions.

--Anne of Winneconne, WI

7-5-02

I have no expertise on this, but I do have small oak seedlings and other plants
coming up under my Blue Spruce.

-- Kathleen of Berea, OH