Woody Plant Propagation for Master Gardeners

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					Woody Plant Propagation for
    Master Gardeners

          Bob Tomesh
      Horticulture Specialist
           Plant Propagation
• The process of increasing the numbers of a
  species, maintaining a species, or preserving the
  vigor of a plant.
           Obtaining Plants

• Purchase plants from a reputable nursery
  – True to name
  – Disease free
  – Virus indexed
• Arrange for spring delivery
• Home Propagation (???Name, diseases)
  Successful Plant Propagation
• Knowledge of technical skills
 – The art of plant propagation
• Knowledge of plant biology
 – Morphology, anatomy, physiology, etc.
• Knowledge of plants
 – Selected method related to conditions and
   techniques to propagate an individual plant
          Plant Propagation
• Sexual Propagation
 – Recombination of genetic materials to form
   uniquely genetic individual
• Asexual Propagation
 – Use of vegetative organs to create plantlets
   genetically identical to parent plant
Sexual Propagation
         Anatomy of a Seed
• Embryo: miniature plant in arrested
• Endosperm (Cotyledons): built-in food
• Seed Coat: hard out covering for
  protection, prevents water from entering
  and initiating germination before proper
          Seed Dormancy
• Quiescent
  – Ripened seed, ready to germinate, waiting for
    the proper environmental conditions for
  – Allows seed to survive over periods of time
• Dormancy
  – Viable seed that will not germinate when in
    proper environment
  – Due to internal or external cause
           Seed Dormancy
• Scarification
  – Physically altering the seed coat to allow
    moisture penetration
  – Natural scarification processes: passing seed
    through GI tract of animals, weathering of
  – Artificial scarification processes: hot water
    bath, sandpaper, etc.

  – Breaks seed coat allowing moisture to enter!
         Scarification of Seeds
•   Seeds with hard seed coats.
•   Scratch seed coat
•   Acid scarification (wash)
•   Place seeds in a covered can with equal
    portions of sand and set in the truck bed
    for a day or two…this will scratch the seed
            Seed Dormancy
• Stratification
  – Exposing a seed to moisture and specific
    temperatures (cold) in order to encourage
  – Degrades chemical inhibitors causing
  – Useful in timing plants for germination in spring
    (Wisconsin vs Florida)
• Process of embryo development
• Internal conditions must be favorable
  – Dormancy broken
• External conditions must be favorable
  – Proper growing environment
• External factors affecting germination
  –   Water (moisture)
  –   Oxygen
  –   Light (or dark)
  –   Temperature
        Propagation by Seed
• Biology         • Applied
  – Pollination     –   Purchasing
  – Anatomy         –   Starting
  – Germination     –   Transplanting
                    –   Collecting
                    –   Storing
        Propagation by Seed
• Biology         • Applied
  – Pollination     –   Purchasing
  – Anatomy         –   Starting
  – Germination     –   Transplanting
                    –   Collecting
                    –   Storing
Requirements for Germination
• Water – first step in germination is
  imbibe of water – water penetrates seed
• Keep adequate supply of moisture to
  insure germination
• Once germination has begun, a dry
  period can kill embryo
• Indoors
  – Small seeds
  – Long season plants
• Supplies needed
  – Grow lights
  – Clean containers (with drainage)
  – Sterile seed starting medium
  – Location with proper ventilation and
Requirements for Germination
• Respiration rate increases during
• Growing medium for germination needs
  to be loose and well aerated
• Reduced oxygen supply will limit or
  reduce germination
Requirements for Germination
• Stimulate or inhibit seed germination
  – Some species need red light to germinate
  – Some require total darkness
  – Some will germinate in any conditions
Requirements for Germination
• Many seeds have minimum, maximum,
  and optimum SOIL temperatures at
  which they germinate.
• Generally, 65o to 75oF is best for most
    Growing-on of Seedlings

• Fertilizing
   – Fertilize seedlings in soilless mix promptly after
      • Do not fertilize before seedlings emerge
      • Food reserve from cotyledons
   – 15-30-15 for good root development
   – Use half rate or lower until seedlings well
   – Follow recommendations on container closely
      • Fertilize at 2 week intervals
   – Fertilizer burn problem with new seedlings
      • Can be mistaken for disease problems
            Seed Saving
• Do not save seeds of hybrid cultivars -
  Seedlings will not be the same as the
• This is why most trees are grafted or
  cutting propagules are taken from named
  cultivars (asexual propagation)
      Reasons for Asexual Prop.
•   Clone desirable specimens
•   Propagate difficult to germinate plants
•   Create larger plants
•   Save desirable plants from disease

• Maintain genetic trait
        Types of Asexual Prop.
•   Divisions
•   Cuttings
•   Layering
•   Grafting
•   Special Techniques
    – Scaling
    – Tissue Culture
 Methods of Woody Vegetative
• Graftage-combining rootstock and scion
• Induction of adventitious roots and shoots.
  – Layerage-rooting while attached to mother
  – Cuttage-rooting stems cut from mother plant
    or shoots generated from mother plant root
 Adventitious Roots and Shoots
• Roots and/or shoots produced from
  abnormal or unusual locations.
• Growing points are initiated on a
  vegetative structure.
• Dividing Plants
  – Division of a mass
    of plants
     • Spring blooming
       plants, divide in
     • Late summer
       blooming plants,
       divide in spring
• Vegetative plant part which is severed
  from the parent plant in order to
  regenerate itself, thereby forming a whole
  new plant
     Types of Cuttings: Stem
• Herbaceous: succulent herbaceous
• Softwood: soft, succulent growth of woody
• Semi-Hardwood: partially mature wood of
  the current season’s growth
• Hardwood: dormant, mature stems
Hardwood Cuttings
               Root Cutting
• Four to 6 inch
  dormant root
  segments are used.
• Adventitious buds
  originate from the
  cambial region of the
• Polarity is important
  for adventitious
• Stems still attached to their parent plant
  may form roots where they touch a rooting
• Severed from the parent plant, the rooted
  plant becomes a new plant
• The vegetative plant
  part remains attached
  to the mother plant
  while it is developing
  adventitious roots
  and/or shoots.
            Layering Methods

Tip Layer       Simple Layer   Compound Layer

Stooling       Air Layer         Stolons
                Tip Layerage
 *Some plants (black
  raspberry) rat-tail.
*Rooting takes place
  near the tip of current
  season’s shoot.
*Dig after rooting and
  before transplanting.
               Trench Layerage
• Trench layering consists
  of growing a plant or a
  branch in a horizontal
  position in the base of a
  trench and filling with soil.
• Roots develop from the
  base of new shoots
• Initiated in spring.
• Wounding between buds
  stimulates rooting.
• Used for many shrubs.
    Mound Layering (Stooling)
• Mound layering
  involves cutting back
  a plant to near the
  ground during the
  dormant season and
  mounding soil over
  the base where new
  shoots will develop.
• Dwarf fruit tree
• Method that joins plant parts so they will
  grow as one plant
• Used to propagate cultivars that will not
  root well as cuttings or whose own root
  systems are inadequate
• Induce growth form (dwarfing)
       Bud/   Scion
Graft Union

          History of Grafting
• Started with fruit, olive and nut trees
• Dates back 3000 years to China
• Found in written records in Rome and
• Now the primary method propagating
  clonal selections,(ie. Delicious, MacIntosh)
• Joining of plant parts by means of tissue
• Rootstock provides the root portion
  (dwarf, disease resistant).
• Scion wood is the parent portion selected
  for its cultivar characteristics.
• Graft union is the healing wound between
  the rootstock and scion.
        Reasons for Grafting
• Increase the number of a plant cultivar
  which is difficult to propagate by
  adventitious rooting.
• Where cross-pollination results in a plant
  different from the parent (apple).
• Seedless cultivars (seedless grapes,
  seedless plants, male plants).
    Other Reasons for Grafting
• Leaf color (Autumn Blaze Maple)
• Flower color (Prairie Fire Crabapple)
• Fruit quality (Delicious Apple)
• Tree hardiness (Bud 9 Apple Rootstock)
• Disease resistance (Nova Easy Grow
• Sexual status (Cotton-less Cottonwood,
  Marshall Seedless Ash, Male Ginkgo,
  Female Bittersweet)
Collecting Dormant Scion Wood
• Collect dormant wood in
  late February.
• Select one year-old water
  sprouts or shoots.
• One fourth to 3/8
  diameter stems (pencil
• Store in moist cool (36
  degree) environment.
Match the Cambial Zone
        Grafting Techniques

Cleft             Bark   Whip & Tongue
Root Graft
  Budding Techniques

T-Bud     Shield       Patch
Bud (Shield) Graft
• Remove loose soil
• Remove dead leaves and stems
• Note root system of plant
  – Spreading
  – Clumping
  – Rhizome
  – Tuber
•   Spreading root systems
•   Many slender roots from center of plant
•   Plants can be invasive
•   Cut with shears or pulled apart by hand
•   Asters, bee balm, lamb’s ear, purple
    coneflower, many common perennials
•   Clumping root systems
•   Many fleshy roots from crown of plant
•   Can crowd own centers
•   Keep one bud/eye with each division
•   Astilbes, hostas, daylilies, orn. Grasses
             Tissue Culture
• Utilizing our knowledge of plant biology in
  order to propagate plant in vitro
  – Able to produce large numbers of plants in
    small amount of space
  – Use plant growth regulators to manipulate
  – Sugar-rich semi-solid agar medium in
    sterilized container
Amelenchier sp.
15 shoots per culture jar
1524 culture jars
4 week rotation
1 round = 22,860 shoots
1 year = 297,180 shoots
Whitespire Senior Birch
Thank You

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