Division

What is division?

Division is the breaking apart of a parent plant into a number of smaller separate pieces. Each piece must have a growing point or a bud and as much root system as practicable.

Division differs from separation in that the detached pieces from the divided plants were not formed as separate detachable plants.

Types of plants suitable for division include what we will call Group A, those with specialised vegetative structures, such as:

• rhizomes

  • pachymorph - produces large slow growing horizontal stem.

  • Leptomorph - indeterminate stems that continue to produce stems at each node eg: bamboo

• tubers

• tuberous roots and stems

• pseudobulbs.

Group B, other suitable plants, include:

• softwooded perennials (SWP)

• herbaceous perennials

• 'clumpies'

What we've called 'clumpies' are plants which form large clumps (eg flax, Strelitzia, Prunus glandulosa). Often these plants form this habit due to the presence of a rhizome or stolon, but included in the 'clumpies' are those plants which are woody perennials rather than those with herbaceous habits. Also included are woody plants which produce suckers which subsequently develop into individual clumps of stems.

Note: that many of the plants in the plant groups listed above are commercially propagated by seed, soft-tip cuttings and/or tissue culture.

For example:

• Canna x generalis (a SWP) can be easily divided but is commercially propagated by seed.

• Ajuga reptans (a SWP) can be easily divided but is commercially propagated by soft-tip cuttings.

Advantages and disadvantages of division

Advantages of propagation by division include:

• a high success rate and a relatively quick turnover--for example, Ophiopogon sp. (mondo grass);

• suitability for slow-growing plants from seed to flower-for example, Clivea sp.

However, there are two main disadvantages.

• There is little commercial application for it, because of the large space needed for

stock plants in order to produce quantities of saleable plants. It is most often used in specialist nurseries for softwooded and herbaceous perennial production.

• It can be labour-intensive, and therefore not commercially viable in most cases, but is extremely useful if small numbers of large, established plants are required.

General guidelines

For propagation by division, you must observe the following guidelines:

• Ensure that correct naming, and proper disease-free, weed-free cultural conditions have been maintained in the selection of plant materials.

• Material must come from a known source in order to ensure the new plants are healthy and disease-free. Weeds are especially a problem in large clumps of plants.

• You must keep damage to plant material to a minimum.

• The newly divided plant should have ample healthy roots, enough to be able to support the foliage.

• The newly divided plant should have buds, or growing points.

• The aerial growth may have to be reduced to balance the root system.