Not a plant that was grown at Monserrate, but familiar to me in the gardens of Madeira. The reason I mention it is to call attention to a blog of Brazilian trees and plants run by Eugenio Melo
http://e-jardim.blogspot.com/. He gives information about the plants discovery and early cultivation - just the sort of information I am always looking for.
Since the blog is in Portuguese, here is a quick summary of what he has to say: The Acanthaceae provide some of the most beautiful flowering shrubs, they are fast growers, generally easy to grow and provide garden highlights to flower beds, walls and borders. Examples include the omnipresent (in Brazilian gardens!) Justicia brandegeana - Shrimp plant - and Pachystachys lutea - Yellow Shrimp (that I struggle to grow in Lisbon). These are both widly used by garden designers in Brazil for their vibrant colours. Indeed Eugenio feels that these tones of red and yellow are easy and common in hot climates. There is howvere a recurring difficulty to find flowers in a cooler tone, especially blue. Hence the post "Azul nos tropicos".
Eranthemum pulchellum was described in 1797 by Henry Charles Andrews, recently married with the daughter of a famous nurseryman in Hammersmith. Andrews published ten volumes of "The botanist's repository for new and rare plants". Palte 86 describes our plant. Seeds were sent by William Roxburgh from the coast of Coromandel. The plants were cultivated in the nursery and at Kew in hothouses.
The plant appreciates a soil with plenty of organic matter, can be grown in full sun or part shade, always well watered.
Um abraço Eugenio!