Genus - Davidsonia
Species - There are 3 Species of Davidson's Plum. Two (and sometimes all three) of which are also described as variants within a species. Gwen J. Harden and John B. Williams' 1999's A revision of Davidsonia (Cunoniaceae) was accepted in 2000. The revision has a 'key to species' section following the evolutionary species concept as outlined by Wiley (1978, 1981) and defines the Jerseyana's rank along side Pruriens as species. This paper also describes the Johnsonii as a species using the same outline.
Species as revised by Gwen J. Harden and John B. Williams 1999
Davidsonia Pruriens - Known as Ooray by the Tully River Aborigines, Davidson's Plum
Davidsonia Jerseyana - NSW Davidson's Plum, Mullumbimby Plum, Davidson's Plum
Davidsonia Johnsonii - Smooth Davidson's Plum
Older references to the Jerseyana may take the form below. Davidsonia Pruriens var. Jerseyana
Davidsonia Pruriens (Ooray, North Queensland Davidson's Plum)
Tree to 18 Meters
Fruit Colour - Purple/Blue skin, with dark pink to red flesh.
The Davidsonia Pruriens is the tallest, and producer of the largest fruit, of all the Davidson's. I've noticed that the fruit flesh can be a little lighter in colour (closer to dark pink rather than the deeper reds you find in a well ripe Jerseyana), however the Pruriens colour does darken (deeper reds) if left to ripen for a number of days post drop. I have a theory that the Pruriens fruit drops a little less ripe than a Jerseyana's fruit does.
The Pruriens tree can grow in full sun from young age. Being a rainforest tree, it responds well to watering, and with protection from the wind there should be less chance of burning or drying out.
Davidsonia Pruriens fruiting times are an advantage with fruit fly due to the fruit forming (most of the time) from March until June. I've also had small crops of fruit form on one of my trees in Janurary and other fruit beyond July at times. The young fruit being very hairy may help repel a few pests as well. I find many native stingless bees visiting the attractive non-fragrant Pruriens flower. I collect the fruit mainly by shaking the trunk of the tree twice a day. I find it better to catch the drop, or at least see where the fruit drops to (from 4 Meters+ it can get some travel once it hits the ground or obstruction on the way down). I also have used a bucket on a stick, as well as a landing net at times to collect or catch the high-up fruit. It seeds readily in well drained, well watered pots or tubes of potting mix or compost and directly in the ground.
Davidsonia jerseyana (NSW Davidson's Plum, Mullumbimby Plum)
Tree to 10 Meters
Fruit - up to 5cm in size
Fruit Colour - Purple/Blue skin, with to red to burgundy flesh.
NSW Davidson's plum develops its fruit in clusters off the main woody trunk and dividing branches. These clusters may develop on very short stems off the trunk, as well as individual fruit developing directly off the main trunk(s) via short stems. In many of its natural conditions, this tree (usually being understory and deep gully) will grow 1 to 3 branches with a bushy top crown terminating each branch. A much wider and shorter habit can be encouraged on these trees by pruning branches at a desired height. The plant usually responds to pruning (and other setbacks on growth) by developing new branches (almost suckers) directly from the base of the tree, as well as developing new branches (at varying heights from the base). New pink growth on a NSW Davidson's Plum (below) A plant exposed to less sunlight (shade house/indoor pot plant) will not have any brown
leaves but usually less and smaller fruit indoors. Some have indicated the hairs can irritate (on both the fruit/trunk and leaves) - my experience is that you really have to be handling them vigorously to get this, and its not usually an issue when brushing past the plant. The North Qld Davidsonia Pruriens causes the most pruriens (Latin for itching sensation) of the 3 species.
The Jerseyana flower's cluster close to the trunk(s) The fruit of this species usually has hairs, but they never have irritated my hands when picking. If you have sensitive skin, use gloves when picking as a precaution and rub the hairs off whilst wearing the gloves. I believe the fruit of the Davidsonia Jerseyana (NSW/SE QLD) is deeper red and a little tastier than the North Qld Davidtson's. It seeds readily in well drained, well watered pots or tubes of potting mix or compost and directly in the ground. Some of my potted Jerseyana plants have self seeded seedlings from the occasional fruit I missed. I also have slowly developing seedlings in a small edible endemic forest, growing within drop zones of the parent trees.
This being currently the most popular, attractive and versatile (indoor/outdoor) of all the Davidson's, I thought I might highlight some points -
|D. jerseyana fruit|
• To avoid itching, wear gloves when vigorously handling branches and leaves (I probably should too).
• If the plant looks dead, take it to shade and give plenty of water, it will probably come back. • They make an attractive pot plant and can be both an indoor or outdoor plant. • Although it is beneficial to have some shade, I have found that the more sun (to an extent) the better the crop, the tree usually develops a less bushy habit in sunny positions. I still find that the mature trees respond best with full morning sun and patchy shade from the early summer afternoon.
• The fruit is smaller and slightly darker in colour (more burgundy) than that of the Qld Davidson's Plum fruit.
• Watch out for Fruit Fly (after all, both the fruit fly and Davidson's Plum's original native habitats overlap).
The Jerseyana is found in isolated pockets of rainforest within the Brunswick and Tweed Rivers catchments of North East NSW. It is classed as endangered in the wild. The plant is in wide cultivation for both commercial and domestic markets.
Davidsonia Johnsonii (Smooth Davidson's Plum)
Tree to 5 to 10 Meters. There also seems to be reference of recorded heights to 18 Meters
Fruit - Up to 6cm Fruit
Fruit Colour - Purple/Blue skin, with red flesh.
This plant can be easily distinguished from the other 2 Davidsonia by its lack of hairs, both on the leaves and fruit, as well as it's fruit being seedless. It grows to a height of 5 - 10 meters and can have many branches dividing from quite low to the ground. These branches form a thick bushy crown. Mature trees may also have younger saplings and suckers growing from the root base. Johnsoii fruits very well with seedless fruit up to the size of 6cm. Although seedless, the fruit still contains a fibrous pyrene without the seed within. It propagates in the wild only via root suckers, which has baffled many as to why it has an extremely scattered wild distribution of 120km. Some suggestions for this anomaly is vegetive distribution by the Aboriginal people of the area and another is that the tree will very occasionally produce fertile seeds (no seed has been found to date). My 2 Johnsonii plants have not produced fruit as yet, so I cannot describe any differences other than the fruit being seedless and smaller than the Davidsonia Pruriens.
This plant can be propagated by cuttings or sucker removal from root base. There are a limited number of locations containing small populations of Johnsonii in Northern NSW and Southern Queensland. This plant is considered endangered in the wild. The plant is in wide cultivation. It is not usually used for commercial crops.
Wild Harvest, Crops and Market
Davidson's Plum have had varying rates of interest over the last 25 years, with it being commented that there's been oversupply since the late 90's. I have heard of some farms starting up again due to re-emergence in market interest of recent years. Interestingly enough, the Plum's popularity in Australia steadily increased from early 1900's peaked (before a decline to almost nil) in the 40s and 50s at similar levels to popularity peaks in the 90s and 00's. My theory is the post war years gave us Australian's wonderfully new exotic fruits to taste which we still love to this day, so we forgot about our tart but beautiful backyard gem.
The source of NSW Davidson's Plum fruit rapidly changed to a 100% commercial farm crop, from its origins of wild collect, which was the main source of NSW Davidson's Plums up until the late 90's. Davidson's Plums has an average farm gate price of up to $40/kg fresh, and with up to $26 a Kilo for frozen de-seeded halves. In 2010, the fruit had a total estimated production of 8 - 10 Tons
|King Parrot (Female)|
• Fruit Fly (Davidsonia J.)
• King Parrot
• Extreme Weather (Drought, Hail, Cyclones)
• Varying market popularity Health Benefits
Below is an extract from a RIRDC document - Focus on Davidson's Plum 'Davidson plum contains high levels of anthocyanins, natural pigments that are strong antioxidants. Its antioxidant capacity is higher than the blueberry, which is renowned worldwide as the ‘health-promoting fruit The substantial amount of antioxidants found in Davidson plum compared to other fruit and vegetables means consumers are able to eat smaller amounts and still receive the equivalent nutritional benefits. Antioxidants are believed to hold a number of benefits for human health, potentially preventing and delaying diseases such as Alzheimer’s disease, autoimmune and cardiovascular disease, cancer, and diabetes. Davidson plum is a good source of potassium and also contains lutein (a compound that plays an important role in eye health and wellbeing), vitamin E, folate, zinc, magnesium and calcium. The skin of the Davidson plum contains the majority of the nutrients, so it is recommended to consume the fruit in full for all the benefits. Due to its intense colouring, Davidson plum can act as a natural food colour without the use of preservatives and additives.'
The anthocyanins mentioned above are the same anthocyanins that are claimed to give the Queen Garnet plum it's unique health properties. I cannot find published results pertaining to the anthocyanin levels of either fruit.
|Native Bee on Davidsonia pruriens flower.|
Davidson's Plum Jam
The Jam I make is simple ... equal weight ... Fruit to sugar.
• Cut and De-seed plums (best to at least quarter, or smaller chunks)
• If you wish, you can reduce the chunks with a whizzy whizz of some kind. Always good to leave a little bit of chunk.
• Weigh the seedless pulp
• Add the same weight of sugar as pulp
• Heat and stir the 2 ingredients together
• Simmer until you have the desired thickness (my guide of checking is to dab a teaspoon of the jam onto a saucer/side of bowl, wait for it to cool. Hold the saucer on its side and run your finger through the dab of jam, the finger line should stay with no jam running). I guess the plum must have ample pectin as it sets well.
I find the QLD Davidson's Plum has a little less taste and a little more zing than the NSW variant. I vary the ratio slightly, pending on Plant type & who I make it for.
Add approx 4 medium sized fruit to 2 Litres of water.Watch the colour transform from clear to pink over an hour or two, and then to red over several hours
Add sugar (if desired) to balance or eliminate the sourness.
A jug of diced fruit can be refilled with water 3 (or more) times once emptied. Each refill will take additional time from the previous to infuse, with the 1st taking approximately 3 hours and the 3rd taking about 24 hours.
**(Hint)** Adding sugar directly to the cut fruit will rapidly draw out the flavour and colour, I sometimes do this on the 2nd or 3rd reuse.
The fruit is exhausted for infusion use when the pulp goes to an almost clear/white and the skin has turned from black, to light red/burgundy. The pulp can then be eaten or used as a filler in recipes (like apple, choko … combination/filler)
More recipes to come ...
Interesting Reads - Links to Articles containing Facts, Sales, Recipes & Comments
A Revision of Davidsonia RSBG 1999/2000