Gwen is the leader of the Society's Epacris Study Group. The following article is reproduced from the March 1999 issue of the Group's Newsletter.
Epacris seedlings often appear in gardens, particularly in areas where soil has been disturbed, but difficulties are often experienced in controlled propagation from seed. The aspects involved in the successful propagation of Epacris from seed appear to fall into four separate categories:
Epacris seed is produced in 5-valved capsules, usually about 3.5 mm long, with numerous very small brown to blackish seeds in each cell.
Seed collection time in south-eastern Australia is often between December and February but this will vary considerably in accordance with flowering period.
A major difficulty appears to be that the total seed on a plant can sometimes ripen and be dispersed on the one day. Unless plants are observed regularly the seed can be lost. As the capsules begin to dry the small brown to blackish seeds can be revealed when a capsule is picked and opened, or are shed when the branch is shaken.
Use a clean dry plastic metal or glass container, without seams where the seed can be caught, and hold it under the fruiting stem. Run one hand along the stem so that the small capsules fall into the container or pick the capsules individually and place them in the container.
Take the container inside or away from an breezes and place the contents in a tea or rice strainer or a similar object with a fine plastic or wire mesh. Stir the contents vigorously so that the seeds fall through into a container below. The husks of the capsules plus odd leaves etc which have been gathered will be retained in the strainer and can be thrown out. You should now have a container of Epacris seed, with perhaps the odd small leaf or fragment of the seed capsule. If there are any tiny insects in the container these should be removed so that the seed is not eaten before you are ready to plant it.
If you are unable to observe a plant carefully until the seed ripens the fruiting stem can be placed in a calico bag which is then tied firmly. It may be necessary to cut the stem at the time of collection. A paper bag can be used but it can disintegrate if it becomes wet during the ripening period. Nylon stockings provide an alternative, but the small seeds and plant fragments can become lodged in the fabric and difficult to remove.
A sheet of fine weed-mat or a plastic sheet can also be placed around the base of a plant to catch the seed as it falls to the ground.
Epacris seed can have a dormancy period, with better germination sometimes achieved if the seed is stored for 12 - 14 weeks prior to sowing.
Seed should be stored in a cool, dry, dark location.
Several growers and researchers recommend that Epacris impressa seed be stratified prior to sowing, or immediately after sowing.
Stratification is used particularly for plants which experience low temperatures combined with moisture in their natural habitat. In cool climates seed can be sown in autumn then left outdoors for the chill factor to be effective during the winter.
Alternatively seed can be sown in a moist mix and the seedling tray placed in a refrigerator for a period of between one and eight weeks. The temperature commonly used for stratification is between 1 and 5 oC. Seeds should not be placed in a freezer, as tissue damage will occur. Another method can be to place the seed with pre-moistened peat moss in a sealed plastic bag near the bottom of the refrigerator for about a month prior to planting.
Seed should be sown in a well-drained medium with the ability to retain sufficient moisture to promote germination. Propagation mixtures of around 3 parts sand plus one part peat moss have been used with success or commercially packaged seed-raising mixes are also readily available.
In addition to conventional seed-raising, where the container is simply placed in a sheltered situation until germination occurs, success has been achieved by using the 'bog method' (where the seedling tray is placed in a container of shallow water) and also by leaving the seed uncovered in the tray and placing it under a misting system until germination occurs.
Germination can take from a few weeks to several months, so don't be too anxious to throw out trays of seed which appear to show no results.
Considerable success has been achieved by using smoke-treatment of seed and propagation medium.
Difficulty has been experienced by growers in achieving successful development of young Epacris seedlings, from the transplanting stage.
The seedlings have very fine roots which must be handled with care when transplanting, to avoid damage. Plants must also be placed in a sheltered situation during this initial development stage.
It is also thought that at this stage the micorrhizal associations involved in good root development may hold an important key to success here, and research is being undertaken on this aspect.
For further information on propagating Australian heaths see the general propagation notes.