T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Echium candicans x E. pininana (Cobalt Tower)

Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Eudicots
(Unranked): Asterids
Order: Incertae sedis
Family: Boraginaceae
Genus: Echium
Hybrid: E. candicans x E. pininana
Binomial name: Echium candicans x E. pininana
Common name: 'Cobalt Tower'

The text below is from NEW ZEALAND BOTANICAL SOCIETY NEWSLETTER. NUMBER 71 MARCH 2003 part of a research report titled  ‘Macaronesian echiums’ by W.R. Sykes, Research Associate, Landcare Research, Lincoln and A.J. Healy, Riccarton, Christchurch.

Echium candicans x E. pininana
Within the last 10-15 years plants that are intermediate between Echium candicans and E. pininana in respect to leaf size and shape, inflorescence length, inflorescence branch length and to some extent flower colour, have become locally common around Lyttelton Harbour on Banks Peninsula.
Such plants now form small populations along the roadside and are here regarded as hybrids between E. candicans and E. pininana. They are apparently not monocarpic like the latter, although they do not live as long as E. candicans and die within two or three years after first flowering. The stems of the hybrid plants either remain single or else they develop a few branches before flowering but the plants do not become bushy as in E. candicans. The densely flowered inflorescences usually vary from c. 70-150 cm long at the fruiting stage and the inflorescence branches are similar in length to those of E. candicans. The flower colour is blue to mauve-blue and usually (? always), pink in bud.
Thus the corolla colour encompasses the range of that in E. pininana and partly covers the range of E. candicans. Considerable variation in these characters can be found in a single small population.
Finally the hybrid plants tend to be at maximum flowering after that of E. candicans and slightly before the late November maximum of E. pininana.
We have not found references to hybrids between these two species in New Zealand or overseas literature so there does not appear to be a general hybrid name for such intermediates as briefly described above. However, this year McCully's Garden Centres and other garden centres in New Zealand have been selling plants of a deep blue-flowered Echium called 'Cobalt Tower' and the label also states that it is from a cross between E. fastuosum (i.e., E. candicans) and E. pininana.
This cultivar is now being raised in large numbers by tissue culture in order to maintain the characters of the clone. The plants are semi-monocarpic but have several branches culminating in flower spikes and the height of the whole plant is about 2.5-3.0 metres. However, the plants can be induced to remain alive and flower again for a year or two by removing inflorescences before the fruits mature.
'Cobalt Tower' was selected from many hybrid seedlings raised by a breeder in Napier (Graham Burton pers. comm.). Echium candicans grows particularly well in the hillside gardens in the Napier area.
A very recent TV gardening show extolled the virtue of this recently named cultivar. However, one of us (WRS) saw and collected similar plants to 'Cobalt Tower' in 1977 in a garden at Prebbleton near Christchurch. They were of hybrid plants that arose by chance after E. pininana and E. candicans were introduced to the same garden. Again, the hybrid progeny clearly showed intermediate characters between the two species.

Photographed road side on the Sumner hills, Christchurch.