[CANUFNET] Medians

Tue Apr 14 16:11:22 EDT 2009

Hello

Really interesting discussions.

Allison - what was the source of the disease resistant elm cultivars?
Sean Fox of U of Guelph Arboretum has evidence that they don't resist
DED well or maybe not well when planted far from their home climates. 

For everyone - how do you define to 'stand the test of time'?  Are you
looking for relatively good survival and health over decades or maybe
only a decade, especially if you are talking a 1 m cube vault?

Barb Boysen, Coordinator 

Forest Gene Conservation Association 

Suite 233, 266 Charlotte Street 

Peterborough, ON K9J 2V4 

Tel: (705) 755-3284 

Fax: (705) 755-3292 

Cell: (705) 875-7150 

barb.boysen at ontario.ca

www.fgca.net <http://www.fgca.net/>  

www.ontariosnaturalselections.org
<http://www.ontariosnaturalselections.org/>  

________________________________

From: canufnet-bounces at list.web.net
[mailto:canufnet-bounces at list.web.net] On Behalf Of Ian Wilson
Sent: March 27, 2009 10:59 AM
To: Canadian Urban Forest Network
Subject: Re: [CANUFNET] Medians

Thanks Alison, and others who've responded.

FYI, here's some of the species we've tried.  We are Zone 6a / 5b so
we've got a few more options:

1)  Red oak - seems to be one of the best overall for salt tolerance and
tree health

2)  London plane - good tolerance to the harsh median conditions,
however they will suffer bud dieback due to salt spray in the winter,
mostly on the lower branches, which causes witch's brooms on the lower
part of the tree.

3)  Norway maple - excellent salt tolerance but they suffer bad leaf
scorch in late summer

4)  Austrian pine - does pretty well, but we have to trim them up for
sightlines

5)  We've tried black locust ("purple robe" variety) but this particular
variety is NOT doing well, mostly because it is so weak-wooded and
breaks apart

6)  Callery pear - a recent trial but seems to be doing ok so far, and
the Chanticleer variety is more upright

7)  Armstrong maple - seems to be doing ok in areas with lower speeds
(not as much salt)

8)  Honeylocust - also seems to do quite well, we have some mature
specimens on our highway medians

In terms of shrubs, we've used junipers and some varieties of Rosa
rugosa successfully.  In the winter they look pretty bleak and the roses
tend to catch the garbage, unfortunately

Ian

	-----Original Message-----
	From: canufnet-bounces at list.web.net
[mailto:canufnet-bounces at list.web.net] On Behalf Of Alison Bond
	Sent: Thursday, March 26, 2009 6:27 PM
	To: Canadian Urban Forest Network
	Subject: Re: [CANUFNET] Medians

	Ian,

	In Collingwood (zone 5a...in southern Ontario's snowbelt) we
find that perennials tolerate snow better than shrubs as they don't get
crushed.  We've tried Rosa rugosa, False Spirea, and Gro Low Fragrant
Sumac with no luck.  Karl Foerster Feather Reed Grass has been extremely
successful in a 1m median (irrigated) and curbside planting beds (not
irrigated.)  It is cut once a year in the early spring (cool season
grass that greens up early) so we have the benefit of the grass in the
fall/winter.

	As for trees, we had moderate luck with honeylocust in a 1m x 1m
x 1m tree vault (the road engineers designed the vaults and we came in
afterwards to 'green things up.'  Covering the canopies with burlap over
winter (not an easy job) improved the survival rate.  The ones that
survived their first year seem to be doing (relatively) well 4 years
later.

	Inspired by the Quebec City Urban Forestry Conference tours, we
recently tried planting one of the Dutch Elm Disease resistant elm
cultivars in a boulevard (zone 4.)  After the first winter there was
100% survival for the elms and serviceberry (A. canadensis), if you can
believe it.  Honeylocust was third.  Red oak (native to the area) did
terribly.  We don't know if it was stock from a warmer seed zone or if
the red oak is just not able to tolerate that much salt and snow (trees
were often buried in 2m snowbanks.)  Anyway, I'd try the elm in in a
median if I were planting trees.

	Finally, I've noticed that if trees are tall enough to have some
of the canopy above the salt spray, they seem to pull through.  We
planted four freemani maples in a boulevard.  As you may know, they grow
almost too fast and the stock at planting was very tall.  The lower
canopy was killed off by the salt but the rest of the canopy seems to be
doing OK...again about 4 years later.  

	Alison

	Alison Bond OALA CSLA
	Landscape Architect and Certified Arborist
	Envision-Tatham

	On Mon, Mar 23, 2009 at 4:48 PM, Ian Wilson <IWilson at kelowna.ca>
wrote:

	I'm looking for information on low-maintenance plant materials
and landscaping designs for road or highway medians that have "stood the
test of time".  I just got a copy of the new "Planning the Urban Forest"
book and saw a photo of an interesting median planting in Urbana,
Illinois utilizing native plants, which got me thinking about what other
cities might be using for medians.

	The City of Kelowna has been developing more medians in recent
years.  We've tried a variety of different designs and plant materials.
Medians seem to be among the most difficult growing sites in terms of
maintenance and plant health.  Here's some of the challenges that we
have had:

	1)  Getting enough soil volume for trees and plants,
particularly in narrower medians

	2)  Salt spray due to winter road maintenance in our climate.
Some trees suffer bud dieback due to salt spray.  Others might suffer
soil toxicity once the salts get too high.  One of the best trees we've
found so far seems to be red oak.

	3)  Sand accumulations in the planting bed.  Even if you have a
nicely mulched bed, after a year or two it all ends up looking like a
bed of sand.

	4)  Worker safety in order to maintain median plant materials
and remove garbage and maintain irrigation etc.

	5)  Landscaping medians on highways with higher speeds - the
additional wind and salt spray etc seems to be particularly hard on
plants when the traffic speeds are higher.

	We have several different designs that we have tried, depending
on situation.  We're starting to move towards a couple of different
designs, one is more of a xeriscape design with trees in a large
planting bed and xeriscape plant ground covers (where we have the
space).  Where speeds are higher and sand and salt accumulation is an
issue we're trying more hardscape with trees in "pits" and hard
surfacing, but unless we use Silva cells or something similar we run
into the challenge of limited soil volumes.

	Anybody have some good designs or ideas that they'd like to
share?

	thanks, Ian

	Ian Wilson, RPF, Certified Arborist

	Park Services Manager

	City of Kelowna

	Park Services

	Civic Operations

	1359 KLO road,

	Kelowna, BC  V1W 3N8

	iwilson at kelowna.ca

	Phone: (250) 469-8842

	Fax:  (250) 862-3335

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.web.net/pipermail/canufnet/attachments/20090414/cc4f29a6/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 7908 bytes
Desc: image001.jpg
URL: <http://list.web.net/pipermail/canufnet/attachments/20090414/cc4f29a6/attachment.jpeg>