Perennials
Amy Jo Detweiler
Perennial
• plants
that live for 2+ years
• once mature they flower
annually
Herbaceous
• non-woody
plants that die
back and go dormant in
winter
Perennial lifespan
• depends
on type of plant,
soil, climate, care, etc.
Perennial types:
ground covers
• biennials
•
border plants
• rock/alpine
plants
•
Perennial types:
herbs
• bulbs
• ornamental
grasses
•
water plants
• ferns
•
Planning & Design
• research
• visit
nurseries, gardens
• neighbors
• consider time
Planning & Design
• yourself/professional
• consider
site
• environment
Stats for The Dalles
• USDA
Hardiness Zone 6-7
• microclimates/frost dates
• annual precipitation ~ 14”
• soils – sandy loam/silty
loam
climate summary at http://www.ocs.orst.edu/
Design principles
balance
• contrast
• repetition
•
harmony
• unity
• dominance
•
Design Elements
• color
• flower
• texture
• fragrance
Design Elements
bloom time
• seasonal
interest
•
function
• mature size
•
Formal Design
• symmetrical
shaped beds
• straight lines
Informal Design
• asymmetrical
shaped beds
• free-flowing beds
Low Maintenance
non-invasive
• resistant
• sturdy stems
•
adaptable
• short/long life
span
•
Do a design
• sketch
out
• use a garden hose
• consider hydrozones
Site considerations
soil
• sun/shade
• wind
• bed/border
•
existing
features
• viewpoint
•
Plant material
• nurseries,
• seeds
• neighbors
• mail
order
greenhouse
Soil
• provides
nutrients
• improves aeration
• address drainage
concerns
Soil
• add
organic matter
• 1/2-1/3
• improve water holding
capacity
Prepare the hole
• twice
as wide as container,
same depth
• amend with soil
Containers
• check
out roots
• avoid planting dry root balls
Following planting
• water
new plants in well
• irrigation type
• root stimulant optional
• mychorrhizae
Mychorrizae
Watering plants
• water
deeply less often
• avoid water on foliage
• once established, as needed
Drip line
Irrigation Test
• dig
down 6-8”
• ball up soil
Using Mulch
• reduce
weeds/weed cloth
• prevents desiccation
• prevents erosion
Using Mulch
• covers
bare ground
• 2-5” deep
• types
Maintenance
fertilization
• weeding
• cutting back
•
transplanting
• dividing
•
Maintenance
• winter
watering ?
• pest management
• reapply mulch as needed
Fertilizing
avoid direct contact with the roots
• wait for establishment
• increase the amount of nutrients
available to the plant
•
Fertilizing
• spring
feeding
• avoid late summer, early fall
feedings
• slow-release, phosphate
Weeding
• weed
cloth
• mulch
• within
a bed
Cutting back
• encourage
repeat bloom
• promote new growth
• control size
Transplanting
• in
spring or fall
• redesigning
• mislocation
Why divide?
• decline
in vigor
• becomes
invasive
• for propagation
How to divide
• every
3-5 years
• early spring, late summer
• dig around drip line
• avoid root damage
Propagation
• seeds
• stem
cuttings
• root cuttings
• grafting(advanced)
Seeding
light soil
• moisten soil
• sprinkle seeds
•
cover with
thin layer of
soil
• repot when
larger
•
Stem cuttings
in morning
• cut 3-5”
• remove
bottom leaves
•
dip in
hormone
• place 1/2-1/3
in soil
• clear plastic
•
Root cuttings
1/4’+ wide
roots, 3-4”
long
• when plant is
dormant
•
plant upright
• when growth
is seen
transplant
•
Other uses
• cut
flowers
• dried flowers
Website
•
http://oregonstate.edu/dept/ldplants/