My Acanthaceae journey

Sunday, 19 February 2012

White form of Justicia carnea, an excellent plant for shaded areas

I have had a passion for warm-climate Salvia for the past 15 years and they have become a vital part of my sunny borders, giving colour and form all through the year. In more recent times, I have become interested in warm-climate plants to suit the shadier sites in my garden, especially those that grow easily without the need for too much cosseting and fussing. I seem to be getting lazier these days! So I've developed a great fondness for plants from the family Acanthaceae, a number of which grow and flower well in shady places - even quite dry shade. They generally thrive in very ordinary soil and need little attention other than a hard prune annually (usually in late winter). Many Sydney gardeners will be familiar with some of these plants, as a number of them have been grown here since the 19th century. Early colonial gardeners found that plants from such genera as Strobilanthes (called Goldfussia in those days), Justicia (known as Jacobinia in earlier times), Thunbergia and Ruellia thrived in our mild climate: in England, they had to be grown in heated greenhouses.

Brillantaisia subulugurica, a long-flowering Acanthaceae plant

There are a number of less commonly seen types that also grow very well in our climate, such as Brillantaisia subulugurica, Pachystachys lutea and Rhinacanthus beesianus species. The range of flower forms in the family is broad (including bells, spires and claw-like shapes); and often it is the showy bracts of the inflorescence that are the most attractive feature, and these last for ages on the plant. The plants usually have interesting foliage - colourful, textured or of a large size that provides a good foliage background feature. In every season there is a variety of plants from the family Acanthaceae in bloom in Sydney.

Justicia brasiliana, another unusual member of the family Acanthaceae

At the moment in my garden, some of my favourite members of the family that are in bloom include a quartet from the genus Justicia. Justicia carnea is probably the most familiar, with its showy pink or white plumes that continue from summer into autumn on a shrub 1.5 m tall. It is an excellent plant for a shady border, amongst shrub or cane Begonia, Plectranthus species and Hydrangea. A less well known species just coming into bloom now is Justicia brasiliana, (previously known as Dianthera nodosa), which is a small shrub (ht 1 m) with dainty, fan-like, pink blooms on arching branches - again thriving in shaded areas. Justicia betonica (ht 1 m) has upright spires of green-veined white bracts enclosing pale pink flowers and is sometimes called the white shrimp plant, as it looks a bit like the more familiar shrimp plant - Justicia brandegeeana - that blooms practically all year round in our climate, with reddish-pink or lime-green 'prawn'-like inflorescences comprised of curving bracts holding small white flowers.

Pachystachys lutea, a showy member of the family

Over the past months, my passion for these easy-going Acanthaceae plants led me to research their history in Sydney gardens, to investigate the current nomenclature within the family, to discover which ones grow best here, and to explore some suitable companion flowers and foliage to grow with them. During my Acanthaceae journey, I met some very enthusiastic gardeners who shared my interest and learned how they grew these plants in their gardens. I have collated the information into an illustrated booklet about the family Acanthaceae, covering 34 species from 15 genera, similar to my previous Salvia publication. I have tried to give an honest evaluation of each plant, including their foibles as well as their positive points. I have provided some propagating tips and have also found where it's possible to buy many of these plants. Booklets are now available for purchase: Please click here for more information.

If you have some shaded areas in your garden that need to be filled with something undemanding but attractive - consider the family Acanthaceae! They are perfect plants for Sydney - or any other warm temperate climate.

Reader Comments

  • By Peta 2758 (Zone:9 - Cool Temperate) Monday, 20 February 2012

    I never give up when I see a plant that really catches my eye, eg your lovely Justicia betonica. Sadly it"s too cold here at Biplin. Perhaps one of those elegant coservatories would do the trick. Or maybe I must accept that we can"t have everything. Sigh... Thanks, Peta. I turned to these plants when I sadly found I couldn"t grow all the cold-climate beauties that I wanted to have! Deirdre

  • By Judie 3160 (Zone:10 - Mediteranean) Monday, 20 February 2012

    You never fail to help me identify plants in my relatively new garden (new to me)So this is what these lovely pink plants are that are blooming everywhere in shade among the tree ferns (Dandenong Ranges) - Thank you! Thanks, Judie. I am interested that those plants grow in the Dandenongs as I thought it might be too cold in winter there for them to survive. Deirdre

  • By Carole 2230 (Zone:10 - Warm Temperate) Monday, 20 February 2012

    I"ve come to love my justicia carnea and now also have a white one as well as a the well named shrimp plant. Perhaps it is because they seem to like my garden so it a reciprocal delight ;-) Thank you Deidre Thanks, Carole. Glad you are enjoying these plants that are also my favourites. Deirdre

  • By Lyn 4570 (Zone:11B - Tropical) Tuesday, 21 February 2012

    I share your enthusiasm for the genera. One of my Brilliantasias grows in the dispersal area of a bio-system and loves the extra water, growing quickly to 2.5-3m. It has been top of the cuttings list for friends. J.nodosa was sold as "Pretty-in-Pink", no botanical name so took some time to identify. Thanks, Lyn. I looked into the name of the "Pretty in Pink" one, and Justicia brasiliana seemed to be the most likely one, though I have seen it as Dianthera nodosa and Justicia nodosa. Deirdre

  • By dorothy 4060 (Zone:11A - Sub-tropical) Tuesday, 21 February 2012

    Hello Deirdre, I do not know this family but am wondering if they will grow in Brisbane - what do you think? Kind regards, Dorothy Yes, they will grow well there as they are in general from warm climates. Some of them do self-seed a bit and may be more likely to do so in Brisbane so that is something to be aware of. Deirdre

  • By Ken 2125 (Zone:10 - Warm Temperate) Friday, 24 February 2012

    Your book on Acanthaceae is excellent! As a tropical -style gardener some of these are familiar but I have been wanting to go further into this plant family. The book fills a huge gap in publicly available knowledge on Acanthaceae - plants of great beauty that grow well in Sydney. Congratulations! Thanks very much for your feedback, Ken! Deirdre

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