Callistemons can be propagated by either seed or cuttings. However, to maintain desirable characteristics of a particular plant vegetative propagation (eg. cuttings) must be used. This also applies to propagation of named cultivars.
|Callistemons have very fine seed - there is enough here to produce a forest! Photo: Brian Walters|
After flowering, callistemons produce seed capsules in rows along the branches and in the majority of cases the seed remains within the capsules indefinitely and can easily be collected at any time. There are, however, a few species that release seed once it is mature. The popular Callistemon viminalis (weeping bottlebrush) is in the latter category.
In the case of species which retain the seed indefinitely on the plant, the capsules need to collected and placed in an open container in a warm position until the fine seed is released. This should occur in 2-3 days. For best results, the capsules should be at least 12 month's old (i.e. the most recently formed capsules are best avoided). With those species which release the ripe seed annually, the plant needs to be kept under observation and seed capsules collected when the capsules commence to open.
Germination of the seed of Callistemon species is usually quite easy by normal seed raising methods. No special pretreatment is needed. Germination should occur in 14 to 30 days, depending on the species.
A common method used for germination of Callistemon and related plants is the "bog method" where the pot containing the seeds is placed into a saucer of water until germination occurs. This results in moisture reaching the seeds by capillary action and ensures that the seeds do not dry out.
Propagation of callistemons from cuttings is generally a reliable method. Cuttings about 75-100 mm in length with the leaves carefully removed from the lower half to two-thirds seem to be satisfactory. "Wounding" the lower stem by removing a sliver of bark and treating with a "root promoting" hormone both seem to improve the success rate.
Further details on general plant propagation can be found at the Society's Plant Propagation Pages.