"Acanthaceae blooms in sprinter"

Some easy-to-grow plants are in flower!
Sunday, 03 September 2017     

Justicia floribunda, syn. Justicia rizzinii

We are now well and truly into 'sprinter' - that transition between winter and spring in Sydney gardens: before spring really arrives but with some gorgeous blooms to interest us. I don't have a traditional spring garden, but I have enough flowers at this time to keep me attuned to the season. As many regular readers will know, I have a particular interest in plants from the Acanthaceae family, and quite a few of these are blooming now, many continuing on from winter! These plants are so easy to grow in our Sydney climate, mostly thriving very well in shaded or part-shaded spots, even where the soil is rather dry.

The good old shrimp plant, Justicia brandegeeana, actually flowers all year round, with its quirky inflorescences comprised of showy colourful bracts enclosing rather insignificant white flowers, and they really do sort of resemble shrimps or prawns! The classic variety has reddish-brown bracts, but other cultivars exist, including the lime-yellow version 'Lutea' (shown above), a tall-growing, deep-red bracted one called 'Big Red' and a pink and yellow-hued combination known as 'Fruit Cocktail'. I also have a dwarf-growing form of the reddish-brown one, which grows only 20 cm in height. Another unusual form I grow has white-marbled leaves, with reddish-brown bracts. The shrimp plant must be one of the easiest plants of all to grow in Sydney: mine were given to me by my mother when I first started gardening, presumably on the assumption that no one - not even her novice-gardener daughter - could kill them! These flowers have cheered me all through winter! Unfortunately, this time of year is when we really should prune them, even though they are blooming well, to keep their shape compact - however, even after hard pruning, there will still be some flowers left and they will come back better than ever very soon!

The genus Justicia in the Acanthaceae family has some beautiful plants among its species, and one that has been flowering already for months and will keep on going for a few more months is Justicia scheidweileri. It is the smallest Justicia that I grow. It is around 20 cm and has attractive silver-veined leaves and chubby spikes of burgundy-bracts enclosing mauve flowers, from late summer to spring. It is a lovely groundcover for a shaded area. I like to grow it amongst silver-leaved rhizomatous Begonia or velvety silver groundcover Plectranthus 'Nicoletta' in a shaded spot, to echo its foliage markings. It self-seeds gently but is so cute that no one could ever mind having more of these plants! Another Justicia that has been flowering from winter and will continue on for another month or so is Justicia floribunda (syn. Justicia rizzinii, shown at the start of the blog). Like most members of the Acanthaceae, it is a trouble-free, easy-care plant for warm temperate and semitropical climates, and at just 1 m tall, it can find a place in the smallest of gardens. From June until October, it is smothered in dainty, pendulous, tubular-bell shaped flowers, each multi-toned in colours of scarlet, orange and yellow. It may layer very gently to form a clump but never enough to be a nuisance. The airy effect of its blooms provides a pretty contrast to more robust flowers that appear in winter and/or early spring, such as orange or yellow Clivia, various bromeliads with orange and/or yellow flower spikes at this time, and nasturtiums. Shrubby Abutilon with their Chinese lantern blooms in a similar range of hot colours are also particularly floriferous when Justicia floribunda is at its best.

Another Justicia out now is the unusual Justicia adhatoda, one of the tallest of this genus, which can reach heights of up to 4 m. It has large attractive shiny leaves that have a lime tinge in their new growth. The flowers are held in spikes and they have the typical two-lipped form, similar to those of Acanthus mollis, and they are white with a purple netting on the lower lip.

I mentioned the blue sage bush, Eranthemum pulchellum, a few weeks back when talking about harbingers of spring. This one grows into a shrub about 1 m tall and has simple flowers of pale or (less commonly) darker blue. It is most useful for a shaded part of the garden, where other plants may struggle. I like it grown nearby cream form of Clivia miniata and pale blue Iris japonica or Iris wattii, which have lovely blooms of the identical hue of the paler form of the Eranthemum, at the same time, and also enjoy a shaded spot in the garden.

Ruellia macrantha (ht 1.5-2 m) is out now too. It has gorgeous large, bright purplish-pink flared funnel-shaped blooms from winter into early spring. Its petals are exactly the same colour as Aechmea gamosepala (ht 50cm) with its thick bristles of purplish-pink bracts tipped with iridescent blue bead-like flowers, in bloom at that same time (pictured here with the Ruellia). Like all the Acanthaceae plants mentioned here, the Ruellia needs to be cut back very hard after blooming is over, to ensure a compact form.

A final Acanthaceae plant I am enjoying at the moment is Peristrophe bivalvis (syn. Peristrophe roxburghiana), a gift from a kind reader several years ago. Colloquially know as the magenta plant, this loose, rambling shrub (ht 1 m) has been flowering for the past two months and is still going strong. It has petite but striking flowers of the most vibrant colour of any plant in my garden. It is growing in quite a shady position and seems to be taking root where its sprawling stems touch the ground. I intend to dot it round the garden in various shaded spots to cheer me up next winter and sprinter!

 Reader Comments

1/5  Margaret - 2122 (Zone:10 - Warm Temperate) Monday, 04 September 2017

The Acanthaceae family is a wonderful one, with so many varieties of desirable plants available. All varieties of my shrimp plants are full of flower, but do need cutting back. An old gardening friend gave me the lime-yellow variety, and always cut her bushes to the ground, much to my amazement. They bounced back, better than ever. I have not tried this, however. J. adhatoda has reached over 4m, but is beautiful; Peristrophe bivalvis has a flower, which is gorgeous - thank you! Glad you are enjoying your Acanthaceae, Margaret, and great that the peristophe has a flower! Good to know it struck from the cutting. Deirdre

2/5  Kerrie - 2104 (Zone:10 - Warm Temperate) Monday, 04 September 2017

I just bought Justica Floribunda. I don"t have a big garden & 50% of it is in full beating down northern sun so until some of the small trees i planted grow up & provide some shade I"m restricted for space for anything but hardy sunlovers. Thought i might put tbe new Justica in a pot on tbe terrace? Many Acanthaceae plants go OK in sun or shade. I think that justicia would be fine in a pot. Deirdre

3/5  Kerrie - 2104 (Zone:10 - Warm Temperate) Monday, 04 September 2017

I"ve got the common brown shrimp plant growing in a wall pot cascading down with a couple of bits upright. Haven"t pruned it but expect I"ll have to repot it soon. Sounds good! Maybe you could give it a light trim? Deirdre

4/5  Helen - 7256 (Zone:10 - Mediteranean) Monday, 04 September 2017

From the photos I think my favourites would be the J floribunda -such a cheery colour at this time of year and the very pretty scheidweileri --the foliage sets off the flower colour so well. Must look gorgeous even when not in flower. Am still battling their badly behaved relative ( Acanthus mollis) --but am enjoying the the beautiful vanilla fragrance of box leaf Azara---this year it is actually doing what the garden writers rave about --filling my little patio with its scent. Many of the Acanthaceae might be a bit too cold-sensitive for your climate but you are lucky to be able to grow so many gorgeous cold-climate plants! Deirdre

5/5  Barbara - 2081 (Zone:10 - Warm Temperate) Monday, 11 September 2017

Deirdre congratulations on yet another informative blog. I have had the pale blue form of Eranthemum Pulchellum in my garden for the past 21 years and didn"t know what it was. Do you know where I can buy the darker blue form of this plant?

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