Plant Selection

Plant Selection

LandscapingChapter 7

Objectives• Describe the origins and forms of the

plant used in landscapes• Explain plant nomenclature• Describe the factors relevant to

proper plant selection

Origins of Landscape Plants• Native Plants

– Evolved naturally within a certain geographic location over a long period of time.• Ex: Eastern White Pine, Douglas Fir

• Exotic Plants– Introduced into an area by some means other than nature.

• Ex: Junipers and Yews are native to China and Japan• Naturalized Plants

– Entered the country as exotics but have adapted so well that they have escaped cultivation and are often mistaken for native plants• Ex: Bird of Paradise is a plant native to South America but grows

like a native plant in the desert of the SW US.

Plant forms available• Woody plants– Trees, shrubs, vines, many ground

covers–May be broken down further into

coiferous and flowering• Herbaceous– Vines, grasses, nearly all plants used to

create floral displays (flowers)

How Landscape plants are sold• Bare rooted• Balled and burlapped• containerized

Bare rooted plants• Dug from the nursery field and then

had the soil washed away from the roots

• To prevent drying the roots may be wrapped in damp moss and inserted into a plastic bag or dipped in wax

• Plants sold in bare-rooted form are usually deciduous species that are small and dormant at the time of harvest

Bare Rooted plantsAdvantages• Light weight• Least expensive

Disadvantages• Harvesting techniques

reduce the root system and slows new growth

• Transplanting season is limited to early spring and late fall

Balled & Burlapped (B & B)• Dug at the nursery with a ball of soil intact around

the root system• Ball size is determined by plant size and standards

established by The American Nursery and Landscape Association

• Once the root ball is dug it is wrapped in burlap and tied or pinned to prevent the soil ball from breaking apart

• Another harvest trend is to replace or supplement the burlap with a wire basket around the root ball

• Essential for the successful transplant of all types of evergreens and large deciduous wood plants

Balled & Burlaped Advantages• Less disturbance to

the root system• Allows a longer season

for transplanting• Allows large plants to

be moved and installed

Disadvantages• Added weight makes

handling difficult• More costly

Containerized• Plants are grown and sold in containers

such as metal cans, plastic buckets, bushel baskets, plastic bags and wooden boxes

• No loss of roots because they are grown in the container they are sold in

• Transplant easily with little to no transplant shock and no loss of growth time

• Young plants—3 to 4 years old or less• Can be installed at almost any time of year

ContainerizedAdvantages• Usually small and easy

to handle• Entire root system is

intact. No harvest injuries to impede transplanting success

• Few restrictions on time of transplant

Disadvantages• Large plants seldom

available• Plants become

rootbound if in container too long

Herbaceous Plants• May be started from seeds• Bedding plants• bulbs

Plant nomenclature (X)• Common name- the name the plant

is know by within a country or region of a country

• Botanical name- name that is used and recognized internationally – Expressed in Latin– Assigned to the plant by a taxonomist

• Important for landscapers to know both the common and botanical names of plants

Selecting the proper plant• Plants need to be selected for more

reasons than sentimentality, easy availability, low price or trendiness.

Selection factors• Role• Hardiness Heat zone• Physical• Cultural Factors

Role factors• What function will it serve in the

landscape?• Architectural element• Engineering element• Climate control• Aesthetic• See fig 7-6 p. 103

Hardiness factor• Will it survive the winter?• Most reliable measurment of a plants

potential for survival is its hardiness rating

• USDA prepares and periodically updates a Hardiness Zone Map

• fig 7-10

Heat Zone Considerations• Not as well studied• Mid 90’s the American Horticultural Society

tracked the number of days various regions of the US experienced tempertures over 86˚F– This is called a heat day

• AHS developed a map similar to the one put out by USDA only for heat

• To view a copy of a heat map go to http://www.ahs.org

Physical factors• Mature size and rate of growth• Density of the canopy with and without leaves• Branching habit• Thorns• Shape or silhouette• Leaf size and thickness• Leaf pubescence• Type of root system• Flowering characteristics• Seasonal variation

Cultural factors• The requirements for the growth and

maintenance of plantings

Summary• Landscape plants can either be native, exotic or

naturalized• Several types and forms available for use• Plants are sold bare rooted, balled and burlaped

or containerized• Flowers also come in a variety of forms• Important to know both the common and

botanical names of plants• Plants should be selected based upon 4 factors-

role, hardiness/heat zone, cultural and physical

Assignment• Achievement Review parts A, B, C, E• 35 points• Due on Thursday