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
Project Sequence
Specifying and Sourcing Native Plant Materials
• 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
•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?
Optimal planting times for site & material
Type of plant material
•Seed
•Live stakes
•Plugs
•Bare root
•Container or barerootedcontainer 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)
Beach backshore Zone 1 ~15,000 sq ft. 3750
spacing stock type quantity
American dune grass Leymus mollis 2' oc plug 2000
silver bursage Ambrosia chamissionis 2' oc plug 1000
gumweed Grindelia integrifolia 2' oc plug 500
beach pea Lathyrus japonicus 4' oc plug 500
big headed sedge Carex macrocephela plug 200
seaside sandplant Honckenya peploides
Ground cover Zone 2 3000 sq ft
salal Gaultheria shallon 3' oc 1 gal 300
beach silvertop Glehnia leiocarpa 2' oc plug 200
silverbursage Ambrosia chamissionis 2' oc plug 100
upland Zone 3 2400 sq ft
nootka rose Rosa nutkana 2g 80
snowberry Symphoricarpos alba 2g 80
Hooker willow Salix hookeriana 2g 80
oceanspray Holodiscus discolor 2g 25
cow parsnip Heracleum lanatum 2g 20
riparian 1800 sq ft
tall oregon grape Mahonia aquifolium 3' oc 3g 100
twinberry honeysuckle Lonicera involucrata 3' oc 2g 100
oceanspray Holodiscus discolor 3' oc 2g 25
cow parsnip Heracleum lanatum 10' oc 2g 40
beach wormwood Artemesia suksdorfia 5' oc 1g 300
understory** 2400 sq ft
Sitka spruce Picea sitchensis 10' 2g 10
shore pine Pinus contorta 10' 2g 10
redcedar Thuja plicata 10' 2g 10
bald hip rose Rosa gymnocarpa 3' 2g 60
snowberry Symphoricarpus alba 3' 2g 60
salal Gaultheria shallon 3' 2g 60
twinberry Lonicera involucrata 3' 2g 60
trailing blackberry Rubus ursinus 3' 1g 100
swordfern Polystichum munitum 5' 2g 100
strawberry Frageria virginiana 2' 2g
kinnickkinnick Arctostaphylos uvisursi
** in event that Evt Parks decides to remove poplars….
switch ROGY to RONU, increase conifer component, add PSME.
Howarth Park Nearshore Plantingimportant key species
included in base planting plan
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 longWhips: soil bioengineering: fascines, brush mats, etc.
.25-1.5 inch dia 4- 6ft longPoles: 1.5 – 3 inch dia 4 - 8ft longPosts: 3 – 12+ inch dia 8 ft – 16 ft long….
VersatileInexpensive to produceEasy InstallationEasy handlingHigh mortalityLimited Species Limited to dormant season*Low maintenanceLow genetic diversity “clones”
Rooting potential
Survival potential
Target plant density
Area to plant
Desired established plant densities
Length of cuttings.
Live Stakesrelatively 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 Salix sitchensis
• Pacific Salix lucida
• Hooker Salix hookeriana
• Scouler Salix scouleriana
• Dogwood• Red osier Cornus sericea
• Rose family• Ninebark Physocarpus capitatus
• Salmonberry Rubus spectabilis
• Honeysuckle• Twinberry Lonicera involucrata
• Snowberry 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
ContainerHigher cost per plantLow handling cost Lower mortalityMost species availableLower skill for planting*Medium mortalityMedium aftercare
Variety of Container types and volumes
4” 1 gal2, 3, 5, 7, 10+
Tall potsPrerooted 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!