Don Ellison has 50 years experience in growing passion fruit. He presently grows them on his property in the Gold Coast hinterland. He regularly travels overseas on horticultural missions and has authored many books and magazine articles. This article is a summary of an information-packed discussion and slide-show presentation by Don at our club meeting on 9 June 2010. Don discussed the major varieties of edible passionfruit including his favourites and some that he has bred on his property. The table below is a summary of the varieties discussed.
Alata This variety crops well. It will self-pollinate in some areas depending on what bees are around. However in some areas hand pollination is necessary for optimum results. Hand pollination is best done in the morning. Coccinea This is an ornamental climber with red flowers but one of the best root stocks. Most commercial growers for some reason want to stick with the Flavicarpa as a root stock rather than try new ones. However Don’s pick of root stocks are this one (Coccinea) and the North. These are very resistant to viruses, while the Flavicarpa is less so. Decaisneana A hybrid cross between the Alata and Quadrangularis. They are better to eat than the Quadrangularis. Don hybridises it by hand, uses the pollen from the Quadrangularis on to the Alata. However, once the plant is growing and established, it will then self-pollinate. Flavicarpa This is a hardy climber with an edible yellow fruit. It is used as a root stock. Gaby’s Red This was developed in Florida jointly by Don and a friend. It was developed from hybridizing a red from Panama and a red from Costa Rica. Gaby developed a major business selling frozen passion fruit from a road-side stall. She cut the tops off passion fruits (in the manner of a boiled egg), scooped out the pulp and mixed it with soft-serve ice cream. She then put this mixture back into the fruit skins, replaced the tops, and put them in the freezer. She then started using some big yellow fruit that Don sent her over to her, and was selling more than 1,000 of them a week at $3.00 each. The business kept on growing and she received a government grant. She now sells a range of other fruits including the fruit part of the cashew nut, and supplies all the supermarkets in her area. She can’t keep up with the demand! Golden Giant It’s the earliest fruiter. Comes in around November/December when there is very little passionfruit in the market. A round-shaped fruit, good for growing on its own root stock. It has quite a lot of pulp. People have had problems with the Panama having very little pulp or seed. Golden Nugget One of Don’s favourites and probably his biggest seller of seed. Has a very full cavity of pulp and is widely found in garden centres. It is about twice as big as a Panama Gold and crops well, particularly in Perth with its sandy soil. Incarnata This is a mauve flowered climber, with leaves used as a natural medicine for insomnia. Don hybridised it to get the ‘North’ mentioned earlier. It sends out underground suckers. Laurifolia This one is popular in South America and England, and should grow well here. Like North, it also survived inundation by over 2 metres of flood water. It will survive cold weather. It has an attractive pleasant-tasting fruit. Don’s friend Gaby in Florida grows them in large pots sitting on black plastic to stop nematodes. Ligularis This is a good eating yellow fruit, easy to break open. It will take a little frost but needs regular fertiliser to keep it going. This is a very heavy fruiting species. Macrophylla This is native to Ecuador and one of the very few shrub varieties of passiflora. It is not a vine. Its leaves can be up to 2 feet (600mm) long. There are about 6 shrub varieties out of the 800 or so different species of passiflora. Maliformis This variety has a very hard shell, and needs a hammer to break it open. It is widely used in Central America, particularly Costa Rica. Misty Gem This variety has been good in the last few years but it lasts only 12 to 14 years before it starts to deteriorate. It has been overtaken now by one called Sweet Heart which has a good colour, a tear-drop shaped fruit, but less pulp than the Misty Gem. North This is the result of one of Don’s many experiments. It is a cross between the Incarnata from America and the common edulis. The Incarnata in America dies down in winter and they use the leaves of the plant to make a tea that assists in the treatment of insomnia. Normally there is a lot of trial and error getting a crop from the Incarnata. However Don crossed it with an edulis and used Colchicine to alter the plant’s biology, and finally got a crop. ‘North’ got its name from its location; it was the northernmost and sole survivor of 3 of these hybrids that Don grew side by side. North has been going for 10 years with no root rot or viruses or signs of dying, including being totally inundated by a flood. Don is working with Carol Newman to produce it as a root stock. Panama Red A vigorous variety with a large fruit. It is a much deeper colour than Pandora. Pandora This is a newer one on the market, and is preferred by some growers to the Panama Red. It doesn’t always have a good skin colour, and this depends where it is grown. It is promoted as a cold-climate passionfruit. Its colour is not always perfect, but it is a reselection of Panama Red and sells better than Panama Red. Purple Giant One of Don’s early hybridised cultivars. It is larger than the normal Passiflora edulis, with good flavour and colour. It is now used primarily as a breeding plant. Quadrangularis This is mostly a self-pollinating variety with football size fruit! Red Perfection This is one Don uses for hybridising. Another good one for this is Tom’s Special. Red Perfection is very red, and Tom’s Special is very black. As an experiment Don delivered 5 different varieties to Woolworths free of charge and asked them for feedback as to which ones sold the best. Red Perfection and Tom’s Special were the 2 best sellers. Ruby This is one of the new ones. It’s about the size of Panama Red or Pandora, but it has a lot of pulp that goes right to the edge of the skin and it weighs a third more than either of those. The only supplier is Carol Newman at Palmwoods who has the exclusive rights to release it. This is the one that will take over from Pandora. Don’s growing tips:
Dealing with frost (and hares): Don places plastic tubes over the stems of young vines as they are planted. The tube is like a plastic bag with no sealed top or bottom, and 3 or 4 small stakes are used to hold the plastic off the plant stem. The plastic protects the stem up to nearly the first row of wire on the fence that supports the vine. Once the plant is above the plastic it just grows up to the top wire. The plants definitely grow a lot faster when planted with the plastic tubes; the tubes give the plant more warmth in winter and prevent hare damage as well. As an additional measure against frost, Don applies foliar-sprays. In the weeks leading up to when frost can be expected, he sprays twice with Seasol, and this is followed by two applications of ‘Envy’ (or ‘Florigard’). Timing is important; the last application of Envy or Florigard should be about a week before the frost comes. In Don’s experience, this gives frost protection to about -4ºC.
Use Weed Mat: Don buys Weed Mat in 100m lengths, and puts it around his plants. It does 3 important things: it stops weeds; it stops evaporation of water, and as yet another frost mitigation measure, it keeps the ground warmer in winter. Don recommends it for all tropical fruit trees that are sensitive to cold. He also recommends buying the lighter weave available at places like Bunnings because it lets through water and liquid fertiliser.
Boron and trace elements: Don had an Incarnata variety that was having problems self-pollinating, but it improved significantly after treatment with trace elements to the extent there was no need to hand-pollinate. According to Don, success at growing all passion fruit depends on the right balance of trace elements. He recommends the Peters brand of fertilisers because they contain most of the required trace elements. However the only thing missing in them is boron which is essential for passion fruit and needs to be added. Boron can be bought in the laundry section of Coles or Woolworths where it is sold as Borax. Don recommends half-a-teaspoon of boron at most in a watering can, along with a teaspoon of iron chelate, and a teaspoon of Epsom salts. One watering-can will do 4 plants.
Fertiliser: Don obtained his best crop ever when he dug plant holes with a post hole digger and mixed into the soil that came out of the holes an 8 inch (120mm) pot of cow manure and the same quantity of chicken manure When he planted the vines he put that mixture back into the holes and added Nitrophoska Blue. Don recommends Nitrophoska Blue as the best fertiliser for fruit trees and passionfruit because it contains most required trace elements but not enough boron. Don said that using proper fertiliser and trace elements, a young plant grown in a pot in a shade house through winter and planted at the end of September will give its first fruit in February – not a huge amount, but quite a few nevertheless.
Don’s answers to members’ questions:
Q. How often do you fertilise? A. I do it every couple of months, but early spring is the best. Q. Do you use the boron once a year? A. No – probably 3 times and the same with fertiliser. I use a lot of potassium nitrate. I put that on with the trace elements. (Note: In Thailand, they spray their longan trees with potassium nitrate and they get 3 crops a year.) Q. When you are growing your passionfruit, do you grow them along wire or a fence, and do you prune them and train them in any way? A. I get 8 foot (2.4m) star pickets and put them in the ground about 1½ feet (450mm). There are two wires on it – the top wire at the top of the picket. They support it all. Q. You said you used an 8 ft star picket with 2 wires? A. Yes – one at the top and one half-way up. Q. How do you prune them? A. I don’t prune them at all. Q. (About the Ruby) Are they all grown from seed or grafted? A. This one (Ruby) is grown from seed. Q. Do these (Ruby) get fruit fly or fruit spotting bug because of their thin skins? A. No, the red ones get very little fruit fly. The yellows are more susceptible. Q. What about the fruit spotting bug? A. These (the reds) are pretty free of problems. Q. How many crops a year do you expect? A. Some of them crop all year round. I expect at least 2 crops and probably 3. The one gap is in November. Q. How long does it take from time of pollination to when the fruit is ripe? 6 to 8 weeks depending on temperature. Q. Do you know anyone who grows passionfruit in large pots? A. Only the woman I know in America because she has a nematode problem. (See ‘Gaby’s Red’ in the first table) Q. Pots would tend to restrict the plant in the end wouldn’t they? A. They seem to come on well in the pots; I was surprised at what good growth she (Gaby) got. While she doesn’t have problems with hares, she has problems with squirrels! Q. Has tissue culture ever been tried in Thailand? A. No but we are working on it. Thailand is not the best place to get tissue culture done on passionfruit; we’re working with Sri Lanka. We are keen to get tissue culture for our plant called North. If that comes off, there should be much bigger crops because of the resistance to viruses. If you look at Nellie Kelly passionfruit, they used a Caerulea as the root stock as it withstood the cold better than the Flavicarpa. Q. The root stocks that you use, are they inclined to sucker? A. They do. It’s one of the biggest problems. If you go down to some of the old passionfruit growing areas like the Murrumbidgee area you will see thousands of them. Q. What causes it? A. It’s just a normal thing. It’s like the Incarnata – it will go 50 metres, and in the right circumstances, so will Caerulea. That’s how it grows in its natural habitat. There are only a few that do sucker in their natural habitat, and the authorities don’t like them coming into Australia, but the fact is they are already here. Q. Have you had any success with the banana passionfruit (Mollissima)? A. I sell huge quantities of banana passionfruit seed grown by a friend in Tasmania. They have been grafted and grow all over Florida. It’s the phytophthora that knocks them and if they are grafted on to any root stock like Flavicarpa, they will grow here. But if you don’t graft, it’s an uphill battle. Q. Which are the varieties most resistant to woodiness? A. Woodiness is the mosaic virus. It is spread by aphids and thrips. The red ones – Pandora, Ruby, Gaby’s Red – are probably the most resistant to it. I have never had one woody passionfruit in any of those. If the North root stock gets going, it might stop the problem. Q. Do you graft any of your varieties? A. Only the Mollissima – the Banana passionfruit mentioned earlier. This is the only one I graft. Others all are grown from seed. (To develop a hybrid) You use basically closed-pollination, so you go out, hand pollinate, and close the flowers off. Q. All your hybrids are actually done by hand? A. They are done by hand. When you are using Colchicine to alter the plant, (say) if I am going to pollinate on to an Incarnata, I cut one of the little buds out of it, near the top, and I put a drop of Colchicine and pollinate on the one above where you put in the Colchicine. If you use the Incarnata as the female, you get a different result to that if you used the other one, the edulis, as the female. It is the same with the big Quadrangularis: I use the pollen from the Quadrangularis on to the Alata to get Decaisneana, but I get a totally different plant if I do it the other way around. Q. When you are bringing seed back in from overseas, what is the best way of separating the pulp from the seed?
A. I have a commercial way of doing it. I cut open possibly 1000 fruit, the pulp goes into a 15-gallon garbage bin. I use 10% hydrochloric pool acid to water. Make sure the water covers the pulp and the seed. Then I insert a paint stirrer on an electric drill and whip it around and leave it for about 2 or 3 hours. Then I come back and stir it again. I have two sieves – one that the seeds will go through but bigger stuff won’t, and the smaller one underneath that the seed won’t go through. I hose it off with a high-pressure hose and it comes out clear and is dried off quickly. If you want to do it at home, get a blender mixer and put elastoplast around the blade (so not to smash up the seed).