Specifying and Sourcing
Native Plant Materials
Introduction to Landscapes on the Edge: Design & Implementation of
Projects on Puget Sound Shorelines and Urban Ravines
Center for Urban Horticulture
November 16, 2016
Scott Moore
Snohomish County Public Works
Native Plant Program
Specifying and Sourcing Native Plant Materials
Project Sequence
• Regional flora
• Project concept
• Secured funding
• Sites assessment
• Restoration plan: goals, objectives, timeline, etc
• Planting Plan: site conditions, soils, elevations, etc.
• Plant palette, numbers, sizes, arrangement
• Specify & Source plant materials
• Site prep
• Planting
• Establishment
• Monitoring
Specifying and Sourcing Native Plant Materials
Target Plant Concept
Specifying and Sourcing Native Plant Materials
Target Plant Concept
Implementation
3 (or 4) Target Plant concepts
• What type of plant material should be used (seed, cuttings, or
plants)?
• What are appropriate genetic sources for each species? Provenance
• What is the proper season for outplanting or seeding (the
outplanting or seeding window)
• What methods will be used to install plant materials & what post
installation plant care is appropriate?
• Right place, right plant
Provenance
• highest regional genetic affinity
• Genetic considerations are fundamental to the success of ecological
restoration
• local versus non-local plant material
• based on sound population genetic, ecological, and evolutionary theory
research;
• selection of plant material to be used in ecological restoration is often
driven by the specific project goals, availability and quality of plant
material, site conditions, and scale of the project.
• issues related to small population dynamics, gene flow in the modern
landscape, and gene expression affecting community structure and
ecosystem functions can affect the success of ecological restoration
activities.
• genetics of small populations (inbreeding and outbreeding depression,
founder effects, and fitness consequences of reduced genetic variation
Seed zones
• Elevation
• Temperature
• Precipitation
• Watershed
Plant Establishment Methods
• Natural Recruitment – maximizing natural regeneration
• Proximity of natural & desirable plant community
• Optimize recruitment
• Direct Seeding
• Outplanting Nursery stock
Planting Season
Optimal planting times for site & material
• Oct to April in PNW
• Coincides with root growth
period
• Fall optimal for woody
plants
• Bare root late winter- early
spring
• Perennials early spring?
• Broader time for container
stock
• Summer?
• Soil moisture or watering?
Type of plant material
•Seed
•Live stakes
•Plugs
•Bare root
•Container or barerooted
container stock
•Salvaged
•Ball and Burlap
Plant materials selection matrix
Acquisition
Availability: commonly occuring? Relatively rare?
Plan early: increased demand,
Sources
Work horse species
Specialist species
Standard specifications
• Common in engineering plan sets
• Common in landscaping plans
• Container vs plant size, caliper, branching, etc.
Plan development and Review
• You maybe creating your own plan in house & doing all the on the
ground work. But your grant source may want to know what your
plan is!
• Or you are reviewing plan from second party (consultant)
• And maybe contracting with a third party to actually do the
construction work
• And maybe a subcontractor is securing plants and doing installation
• And a plan and specifications will help in estimating costs.
Specification minimums
• Plant name
• Common
• Scientific (Genus species)
• Quantity
• Size (container or material type)
• Spacing
• Per acre (trees per acre, tpa) (shrubs per acre, spa) 435 tpa = 10’ OC
• On center (3 ft on center)
• Plant type (evergreen or deciduous)
• Other
• Soil moisture
• Light regimen
• WL indicator rating (OBL, FACW, FAC, Upland)
Howarth Park Nearshore Planting
important key species
included in base planting plan
Beach backshore
Zone 1
~15,000 sq ft.
spacing
American dune grass Leymus mollis
2' oc
silver bursage
Ambrosia chamissionis 2' oc
gumweed
Grindelia integrifolia 2' oc
beach pea
Lathyrus japonicus
4' oc
big headed sedge
Carex macrocephela
seaside sandplant
Honckenya peploides
Ground cover
Zone 2
salal
beach silvertop
silverbursage
upland
nootka rose
snowberry
Hooker willow
oceanspray
cow parsnip
Rosa nutkana
Symphoricarpos alba
Salix hookeriana
Holodiscus discolor
Heracleum lanatum
stock type quantity
plug
2000
plug
1000
plug
500
plug
500
plug
200 understory**
3000 sq ft
Gaultheria shallon
3' oc
Glehnia leiocarpa
2' oc
Ambrosia chamissionis 2' oc
Zone 3
3750 riparian
1 gal
plug
plug
300
200
100
2400 sq ft
2g
2g
2g
2g
2g
80
80
80
25 **
20
1800 sq ft
tall oregon grape
Mahonia aquifolium 3' oc
3g
twinberry honeysuckle Lonicera involucrata 3' oc
2g
oceanspray
Holodiscus discolor 3' oc
2g
cow parsnip
Heracleum lanatum 10' oc
2g
beach wormwood Artemesia suksdorfia 5' oc
1g
100
100
25
40
300
2400 sq ft
Sitka spruce
shore pine
redcedar
bald hip rose
snowberry
salal
twinberry
trailing blackberry
swordfern
strawberry
kinnickkinnick
Picea sitchensis
10'
Pinus contorta
10'
Thuja plicata
10'
Rosa gymnocarpa
3'
Symphoricarpus alba 3'
Gaultheria shallon
3'
Lonicera involucrata 3'
Rubus ursinus
3'
Polystichum munitum 5'
Frageria virginiana 2'
Arctostaphylos uvisursi
2g
2g
2g
2g
2g
2g
2g
1g
2g
2g
in event that Evt Parks decides to remove poplars….
switch ROGY to RONU, increase conifer component, add PSME.
10
10
10
60
60
60
60
100
100
Seed
• Low Cost?
• Easy handling
• Native seed more widely
available
• Contract collection
• Commercial seed
production
• Non-native placeholder?
• Low maintenance
• High genetic diversity
Seed Considerations
• Grass, herbs, shrubs
• Acquisition/availability
• Origin
• Hand collected or field
production
• contract grown
• Direct seed or nursery
production
• Expense
• Application methods
• Keep mixes simple using
common species
Cuttings:
piece of stem, branch, or root, separated a host plant and used to create a new plant:.
Live stakes: .5 – 1.5 inch dia 2-4 ft long
Whips: soil bioengineering: fascines, brush mats, etc.
.25-1.5 inch dia 4- 6ft long
Poles: 1.5 – 3 inch dia 4 - 8ft long
Posts: 3 – 12+ inch dia 8 ft – 16 ft long….
Rooting
potential
Survival
potential
Versatile
Inexpensive to produce
Easy Installation
Easy handling
High mortality
Limited Species
Limited to dormant season*
Low maintenance
Low genetic diversity “clones”
Target plant
density
Area to plant
Desired
established
plant densities
Length of
cuttings.
Live Stakes
relatively short length cutting inserted
vertically into ground.
Vegetative applications and
installations
Ravines, Steep slopes, and Bluffs
soil plant bioengineering strategies
Plants appropriate for live staking
• Willow
•
•
•
•
Sitka
Pacific
Hooker
Scouler
Salix sitchensis
Salix lucida
Salix hookeriana
Salix scouleriana
• Dogwood
• Red osier
Cornus sericea
• Rose family
• Ninebark
• Salmonberry
Physocarpus capitatus
Rubus spectabilis
• Honeysuckle
• Twinberry
• Snowberry
Lonicera involucrata
Symphoricarpos albus
Rooted cuttings
• Increased resiliency
• Summer bioengineering
installations
• Browse protection
• Provide better leaf area to root
area ratio
• Low soil volume container plant
• Pre-rooted live stake
Bareroot
Great care in handling
Greater skill for planting
Low cost
Medium mortality
Medium aftercare
Seasonal availability
Don’t let those roots dry out!
Bareroot
sizing, provenance, availability
wacd-pmc
Plugs
usually herbaceous plants and graminoids
Low cost per plant
Low handling cost
Lower mortality
Limited species
Medium planting skill
Low - Medium mortality
Container
Higher cost per plant
Low handling cost
Lower mortality
Most species available
Lower skill for planting*
Medium mortality
Medium aftercare
Variety of Container types and volumes
4”
1 gal
2, 3, 5, 7, 10+
Tall pots
Prerooted livestakes
Variety of containers
• Containers (variety of volumes)
• 4”
• 1gal
• 2, 3, 5, +
• Tall pots
• Prerooted livestakes
Salvaged material
• Transplanting difficulty is species
specific
• Site permission
• Positive plant identification,
• Some difficulty in prep/digging, and
handling/transporting..
• Storage/Nurturing
• Don’t lose your Ethics
Balled and Burlap (B&B)
• High cost per plant
• Lower mortality?
• Limited species
• Greater skill for planting
• High aftercare needs
• Check for severe root pruning
Estimating your plant needs
• Desired space/acreage to plant
• Available funds
• Plant spacing per stock type
• Many online plant calculators
Spacing
Function- (landscaping, change light/water regimes, mortality rates,
erosion control)
Habitat – desert, wetlands, forests
Existing site conditions (invasive species, existing trees or native
shrubs)
Spacing
In general-
Trees 8 – 20’ OC (100-700 TPA)
Shrubs 2 - 4’ OC
Groundcovers 1-2’
Live Stakes 1-3’ OC
Spacing and cost calculators available on line
Sources of Native Plants
Regional PNW Native Plant Nurseries
Just Google it! Or WNPS.org, local county
from inventory
contract grow
Conservation District Plant Sales
Salvage or on site harvest
Contract Seed collectors
Contingency
• Site conditions change or are not as indicated in
plan set
• Mortality
• Alternative Sources
• Substitutions
• Unicorns
Go Plant!