Experts and Answers
After seeing the R. calendulaceum in bloom at the Arnold Arboretum last June, I have become obsessed with the desire to collect the best forms of this and other native azaleas that have been found. There are magnificent specimens in Arnold, Morris, Tyler and other arboretums, in private gardens, and in the mountains - but there has been very little propagation to make them available.
So, I have set out to learn how to propagate calendulaceum by cuttings and I find information very hard to come by. Rooting Exbury hybrids now seems to be routine, but I am told that rooting calendulaceum presents special difficulties. Have the difficulties been solved? Easton, Conn.
The problem of rooting R. calendulaceum is still one of the more difficult procedures, basically the same as for rooting the Exbury and other hybrids. It seems that many of the non-stoloniferous forms of native azaleas are still extremely difficult to root. This procedure seems to come from softwood cuttings under mist. The problem of rooting is still to get the plant to go through the first winter. It has been found that the rooted cuttings must be forced into active vegetative growth during the same season of rooting to reduce the mortality over the first winter.
We still find a great deal of variability. Some of the cultivars or selections are easy to root, whereas some others are very difficult to root.
Seeds of R. calendulaceum are very easy to germinate.
Another method of rooting is by root cuttings. This is done by taking pieces of the root, pencil-sized, approximately 4" in length, at almost any season of the year, laid horizontally, covered lightly with sphagnum moss. The root cuttings. This is done by taking vegetative shoots. - Fred Galle, Callaway Gardens, Pine Mountain, Georgia.