Rollinia Tips

  • Seedlings of Rollinia deliciosa can start producing in 2 years.  Ref:  Oscar – Hawaii
     
  • Rollinia  Best growth on well drained sandy loam. Root rot and collar rot appears easily contracted when roots are exposed or damaged by soil movement or excessive tree vibration. Strictly tropical. Intolerant of cool temperatures. Temperatures as low as 3°C will kill young trees. High humidity is also necessary for effective pollination. Water stress causes premature ripening of fruit so irrigation may be necessary during flowering, fruit set and early maturation. Trees are shallow rooted and are prone to wind damage. If you Google hand pollinating rollinia, click on the link from books.google which goes to a book called Tropical Fruits Volume 2 and it gives quite a bit of information on Rollinia in Chapter 1.    This gives photographic information on pollinating the Cherimoya – very similar.   http://forums.gardenweb.com/forums/load/tropical/msg0701052322783.html
     
  • One of our members had a problem with his Rollinia not setting fruit so here are a few articles that I’ve collated. The following is from one of our members, Bruce McLean in Brisbane.  I have small sachets of PVC that can be added to the pollen which enhances your chance of successful pollination as it adheres better. I've been asked about Rollinia hand pollination a few times so thought I'd put up a few pictures to illustrate it a bit. I was hoping to do a quick video but haven't had the time and a second person to shoot. Anyhow, I'll try to guide you through the pictures. First step is being able to identify your flowers. Here is a picture of a male and female next to each other. This happens very rarely on my tree but later in the season I get male and female crossing over a little. Earlier in the season I get females one day and males the next or even the day after as it’s a 2-3 day cycle. Female is on the left and is slightly greener and has a very small opening to the flower. The male on the right is a stronger yellow and is open a bit wider. If you are used to other Annona (Atemoya, Cherimoya and Sugar Apple) then the difference between small and large opening on Rollinia will seem fairly subtle, but if you observe them for a while you'll easily work it out. If you want to check you have worked out your males from females, then just remove one of the 'Mickey Mouse ears' petals to check on the internal organs. Female first then male. So, once you can identify your males from females you can go about transferring pollen from the males to the females. Often you will need to collect pollen one night, then store it in the fridge for 24-36 hours, then come back to pollinate the females as they flower on different days. There will be some crossover during the later season, but the majority of flowers are in different stages on different days. I collect the pollen from the males by removing the entire outer flower structure and letting it fall into a small chinese style container made of stainless steel. I then store in the fridge overnight and come out the next evening with my trusty small tipped natural fibre paint brush and find my female flowers. The opening is too small to get the paint brush tip in, so you should remove one of the 'Mickey mouse ears' which gives access to the inner flower. Then get a bit of pollen on your brush (usually mixed with the stamen) and get it onto the sticky part inside the flower (ovary? these guys don't have stigma, do they?). Then move to the next one. Removing one of the petals allows you to mark the ones you've pollinated to check how effective you've been. I don’t pollinate the next day, so I don't remove the petals of the ones I've pollinated, so I can check how it’s gone. Hopefully in a few days you'll get the fruit. Tree overall has a few less than 30 fruit out of about 100 originally set. Hand pollination certainly increases fruit set but the tree will only ever hold what it wants to hold. My tree gets heaps of water - the ground under it has been jelly for many weeks, but it is well drained. Mine also has a huge tap root and very little near surface roots so deep watering helps feed it and keep it healthy. Mine would have had probably 2000 flowers as a conservative estimate this season for the 100 fruit set and sub-30 fruit held... I use half a bag of Organic Xtra in late winter and spread it all around under the canopy as well as going further out. If the foliage looks as though it needs perking up, I’ll spray it with Seasol. I also use a boron spray on the flowers just before they open.  Ref:  Bruce Morgan