Ornamental Plant Propagation: Seeds & Vegetative Methods

Posted on Mar 9, 2025 in Biology

Ornamental Species Propagation Techniques and Management

Different propagation methods exist, depending on whether the species reproduces sexually (via seeds) or vegetatively (asexually).

Sexual Propagation (Seeds)

Sexual propagation involves the union of male and female sex cells to form a seed. Seeds are typically sown in seedbeds during the spring.

Substrate

Peat is the best substrate for initial propagation. After several weeks, when the shoots have grown, it’s better to transplant them into compost.

Sowing Seeds in a Pot

Instructions:

  1. Fill the container up to 1.5 cm from the edge.
  2. Press down the substrate.
  3. Sow seeds evenly, avoiding overcrowding, which can lead to weak seedlings.
  4. Some seeds only require gentle firming or pressing into the substrate.
  5. After sowing, moisten the substrate using a base plate to allow water to soak upwards.
  6. Subsequent watering is preferably done with a misting bottle.
  7. Cover the container.

Germination

Germination requires moisture, nutrients, oxygen, and warmth (ideally between 16-18°C). Germination time varies from 4 days to 3 weeks. Monitor seedlings starting when the first leaves emerge.

Care of Seedlings

When the first true leaves appear, transplant the seedlings into individual pots filled with seedling compost. Always handle seedlings by their leaves. Protect them from cold and water them regularly, especially when outdoors.

Vegetative (Asexual) Propagation

Vegetative propagation uses parts of the original plant (cuttings, layers, suckers, divisions) to create new plants. This is also known as vegetative multiplication.

Cuttings

A piece or portion of the plant (root, stem, or leaf) is taken. Multiplication by cuttings is generally easy, but some plants don’t root readily. Cuttings can be:

  • Hardwood cuttings (taken from dormant, mature stems)
  • Semi-hardwood cuttings
  • Softwood (herbaceous) cuttings
  • Leaf cuttings

The diameter of the cutting should be 12-15 cm, and applying rooting hormone is often necessary.

Herbaceous or slightly hairy nursery cuttings: Best taken in spring and early summer, leaving 2-3 leaves, with a length of 10-15 cm.

Leaf Cuttings

There are three types of leaf cuttings:

  • Leaf with petiole
  • Whole leaf
  • Leaf fragment

Layering

Layering encourages root development on a stem *before* it’s cut from the parent plant.

  • Simple Layering: Suitable for plants like jasmine.
  • Double Layering: Used for plants like *Hydra*.
  • Multiple Layering: Similar to double layering, but multiple layers are created from a single branch.
  • Air Layering: Used for climbing and indoor plants (e.g., *Ficus*, azalea, camellia, cassava).
  • Mound (Stool) Layering: Used for a large number of species, including *Anthurium*, *Aspidistra*, *Aglaonema*, and *Calathea*.

Division (Suckers, Runners, Foliar Embryos)

  • Suckers: Tiny plants that grow at the base of stems (e.g., pineapple, cassava, *Captus*, *Echeverria*).
  • Runners: Long, trailing stems that root easily (e.g., ribbon fern). This is only done during the growing season.
  • Foliar Embryos: Keep the compost moist and out of direct light (e.g., *Kalanchoe*).

Reproduction of Ferns

Ferns reproduce by spores, unlike most other plants. Spores are grouped in *sori* (singular: sorus), contained within a structure called a sporangium. Spores are typically collected only once per year when they turn brown, indicating maturity (ideal temperature: 22-25°C, humidity: 80%).

  • Stolons (e.g., *Nephrolepis*): Long, thin stems with buds that reach the ground.
  • In Vitro Culture: Requires specialized facilities and is not typically done by amateurs. The gametophytic phase of the fern develops from the spore (e.g., *Nephrolepis* ‘Teddy Junior’).

Multiplication by Bulbs, Corms, Tubers, and Rhizomes

These specialized plant structures are multiplied by dividing them.

  • Bulbs: Underground storage organs (e.g., *Amaryllis*, lily, tulip, iris, *Clivia*, *Galtonia*, *Crinum*, *Vallota*).
  • Procedure: Cut the flowers and leave 1-2 leaves to allow the bulb to accumulate more reserves. Bulbs like tulips, daffodils, and crocuses should be kept dry.
  • Corms: *Gladiolus* leaves are covered with scales. The best time for division is in autumn.
  • Tubers: *Begonia*, *Caladium*.
  • Rhizomes: Indian cane, lily. These are underground stems. *Orchid* (*Cattleya*) pseudobulbs are thickened parts of stems, often aerial.

Seed Replication

Planting seeds is used to propagate new varieties.