What size container and soil should be used for an imperial blue cape plumbago?

Hello Wayner49
In answer to your question, I'm quoting from Botanica 1997 edition, p691. If you can get a copy of this weighty tome over there, it's worth its weight in gold.
CULTIVATION
Plumbagos require well-drained soil, perhaps enriched with a little organic matter. They grow best in warm climates; in frost prone areas they do well in a mildly warmed greenhouse.
Established plants are tolerant of dry conditions, but soil should be kept moist during summer, for a good flowering display.Prune in late winter to tidy their vigorous stems, and remove old wood to encourage new growth and next season's flowers.
Plumbago auriculata.
This fastgrowing species from South Africa grows to 1.8m tall with a similar spread and carries its prolific blue flowers through the warmer months....
It suckers readily and grows higher on supports or by climbing nearby shrubs. It is cultivated as an informal hedge, or as a trimmed formal hedge.
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Given all this, I would suggest a good quality multipurpose compost and continue potting on until it is the size you want it.
Apologies for the delay in answering. I've only just seen the question!
All the best

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