This plant is very aptly named as its leaves are star-shaped, heavily overlaid with silver. It is a thick-stem and, for me, one of the most attractive of this group. The Thompsons, in their book Begonias: A Complete Reference Guide, classify this plant as trunk-like, non-ramified. Others in this group are B. ‘Rudy’ and B. ‘Silvador.’
Trunk-like, as the name implies, means that the mature stem looks like a tree trunk. Non-ramified is a term meaning that it will not branch freely. Instead of branching the plant will slowly send up new stems from the basal area. Very possibly, like B. ‘Rudy,’ when mature and happy with its growing conditions, this plant will send out underground stolons which will give rise to new stems. B. ‘Star Frost’ is a cross between B. carolineifolia and B. wollnyi. The female plant is rhizomatous with palmate leaves. B. wollnyi, the male, is semi-tuberous, upright-growing, with silvery leaves and similar to B. dregei. Only the mysteries of hybridization can explain the serrated, star-shaped leaves of the plant. B. ‘Star Frost’ was created by Michael Kartuz in 1977 and registered with the ABS as #566.
Cultivation of this plant is relatively simple. It is easy to grow if treated like a rhizomatous plant. Water somewhat sparingly and keep it potbound in a shallow container. It likes bright light, but only limited sunlight if grown outdoors as the leaves are thin and easily burn. Frequent fertilization will encourage robust basal growth.
This plant can grow to a few feet in height if not pruned. The tip cuttings can be propagated. Unlike the procedure used for most other Begonia cuttings, these cutting should be allowed to callous before planting to discourage rot. The pruned stem (trunk) will often produce more than one new shoot, but always at the end of the stem at the site of the cutting