I had Bud.118 rootstocks growing roots under foil which I'd employed as
rodent protection. The problem came from leaving the foil on, thru the
growing season, and the trunks were more moist than they should have been.
Roots grew mostly from the graft area.
I haven't worked with M9, sorry, but I believe modified tissue growths occur
when the area on the plant is kept both dark and moist.
tc, s.WI
----Original Message Follows----
From: Jason MacArthur <>
To: nafex@
Subject: [NAFEX] Burr Knots
Date: Tue, 9 Mar 2004 06:39:57 -0500
I recently planted a small orchard of dwarf apple trees. In order to limit
both vole and borer damage I made little screen skirts with foam collars for
the trees, as I have seen described in a couple of locations. My question
is, with M9 rootstock being highly susceptible to burr knots as it is, am I
asking for trouble by having the foam in contact with the tree essentially
year round? The foam seems to dry out but it will still always be dark
underneath it. These collars are approximately 18" off the ground, so they
are not grabbing the rootstock but rather the scion. Does anyone have any
experience or thoughts on this?