Queensland Poplar and other Botanical Treasures

Homolanthus populifolius (Queensland poplar)

For years, I had seen this unexpected botanical treasure pop up in gardens and always wondered about it.  I enjoyed gazing at its heart-shaped leaves and red petioles (leaf stems) but was forever befuddled by its identity.

My desire to learn the name and the origin of every plant is probably not healthy – few obsessions are good for you — but what can I do?  It is a combination of awe and endless gratitude that draws me to this pursuit.
Only God is more pervasive, and more giving and sustaining, than the vegetation around us.  We could not live, or even breathe, without plants.  Plants provide our oxygen and our food, our shelter and our clothing, our medicine, spices, and perfume, to say nothing of beautiful, sweet-smelling bouquets.  God is the ultimate mystery but at least there are resources for divining names and origins of mysterious plants.
I was surprised to learn that the volunteer plant with the foliar hearts comes from the Australian rain forest.  Known as Queensland poplar (Homalanthus populneus), it grows into a large shrub or small tree.  It’s sometimes called bleeding-heart tree on account of its leaves, which turn bright red before dropping from the plant.  Emerging foliage is pink to copper and soon takes on a pleasant green color that is somewhere between emerald and lime.  Leaf drop occurs throughout the year but only a freeze will completely denude it of foliage.  If temperatures stay below freezing for long, it will die.
Queensland poplar is a member of the spurge family (Euphorbiaceae), one of the most successful plant families, with habitats that span the globe and include every climate zone, from tropical to desert.  Queensland poplar, although it lives for about 10 years, is a highly desirable ornamental selection since, in our part of the world, it only grows to a height of ten feet and is virtually maintenance free.  Moreover, you need not despair of its short life span due to its easily germinating seeds that will provide you with a constant collection of fresh plants.
Unlike Queensland poplar, slipper plant (Pedilanthus bracteatus) is a spurge family member that is not commonly encountered as a volunteer or in any other capacity.  In fact, in 30 years of plant watching, I had never seen one before encountering it in Malibu just a few days ago.  Despite the local dearth of slipper plants, they are actually hardier than Queensland poplars and, once established, are highly drought tolerant and withstand cold temperatures down to 25 degrees or colder.
San Marcos Growers, in Santa Barbara, has a number of both Queensland poplars and slipper plants in stock.  Although San Marcos Growers are not open to the general public, you can find local nurseries that they supply through their website at www.smgrowers.com.
Speaking of local nurseries, I happened to visit Sperling Nursery in Calabasas the other day and could not help but notice several contorted filbert – commonly known as hazelnut — (Corylus avellana ‘Contorta’) specimens.  If you are looking for an exotic hedge, this is the plant for you.  The contorted hazelnut was first discovered in the mid-1800’s when a plant with twisted and spiraling stems was found growing in a hedgerow in Great Britain.  Shoot cuttings were taken from the contorted plant and cloned offspring were soon being planted far and wide.  It also makes an exotic stand alone garden accent or curiosity  One of the plant’s common names is Harry Lauder’s walking stick, a tribute to a Scottish entertainer of that era who used various kinds of misshapen walking sticks in his comedy act.
Contorted or corkscrew filbert/hazelnut makes a memorable deciduous hedge.  It is especially noticeable in winter when leaves have fallen.  At a mature height of ten feet, it may also be utilized as a security fence since its tangled growth creates a virtually impenetrable barrier to trespassers.  In spring, golden male catkins provide quite a show, even while females flowers, that are borne separately, are non-descript.  It is relatively free of pests and diseases.
The contorted filbert tree, even in its cold winter habitat, seldom produces nuts and, even if it did, Southern California winters are too warm for any sort of hazelnut production.  In the US, over 99% of hazelnuts, harvested from standard filbert trees, are grown in Oregon with the remainder coming from Washington.
Phantom Corokia (Corokia virgata x ‘Phantom’) is a fitting companion to corkscrew hazelnut.  It’s a plant that provides interest in all four seasons.  Growing five feet tall and three feet wide, it has brown tinged foliage that is silvery underneath.  Its shoots grow up in an undulating fashion, rather than straight, as if in response to a snake charmer’s pungi.  Star shaped yellow flowers in autumn are followed by red winter berries.  Phantom Corokia will need to be soaked once a week, and occasionally more often, in hot weather.
Tip of the Week:  Although oxalis (Oxalis corniculata) might conjure up the image of a terrible weed, many ornamental oxalis species and cultivars are available in the nursery trade. Most types grow from bulbs or tubers, many bloom at this time of the year, and all are perennials that persist in the garden for years and years.  They are easily recognizable by their trifoliate foliage that will remind you of clover.  Oxalis, also known as sorrel, is highly touted as a medicinal plant.  Due to its vitamin C content, sailors in the sixteenth century chewed on oxalis to avoid scurvy.  Its active ingredient, oxalic acid, may be effective in treating a variety of maladies, from sore throat and fever to bladder infection and venereal disease. But don’t over indulge. Oxalic acid absorbed in large quantities can be toxic.

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