The responsibility of the Oman Botanic Garden propagation team is to propagate Omani native plants. Initially the challenge was to propagate seed and cuttings in an extremely hot climate. Through collaboration with horticulturists from Royal Botanic Garden Edinburgh (RBGE) and with botanic gardens from Australia, successful protocols were developed and we continue to conduct research projects to experiment with new propagation methods for the native plants – many of which have never been propagated before.
Plants are propagated by seed or through cuttings, division and air layering. Seeds are collected in the wild by the Botany and Conservation team, and after they have been identified and cleaned, the seeds are given to the propagation team for sowing. The number of seeds collected and the number of plants grown corresponds with the planting designs for the garden.
Prior to sowing, a propagation number is created in a plant data base table where all relevant information about each seed is recorded. The optimum treatment for seed germination is investigated, and various pre-sowing treatments are considered – including, for example, soaking in water, scarification, putting the seed in a fridge to break dormancy. After pre-sowing treatments, the seeds are sown into seed trays with a seedling mix that suits the individual needs of the plant. Each pot has a unique label that contains the lineage of the plant. Seed trays are kept in a propagation house and, once the seed has germinated, the seedlings are planted in small pots and moved to glasshouses and polytunnels.
An important horticultural practice is the cultivation of plants from cuttings. Fresh cutting material, either collected in the field or from the nursery, is received in the propagation house. Pre-cutting preparation includes sterilising plants with a mild bleach solution and removal of dead and diseased tissue. Only healthy cuttings are prepared. To induce root growth, heat from underneath is used, and intermittent mist from above prevents the plants from drying out.
There is no horticultural manual on how to propagate native Omani species. Some of the propagation is trial and error. To date, 358 species from 73 families have been successfully propagated.