The Riverside® Passiflora Hybrids

Riverside® Hybrids – Our vision

“Our vision is to supply growers with hardy and distinct polyploid hybrids. This ensures that the hybrids which we release are easy to care for, vigorous, hardy, free-flowering and spectacular.”

Myles S Irvine

Myles S Irvine

Riverside® Hybrids Passiflora breeder

Myles Irvine has been growing Passiflora for over 30 years and has released a number of hybrids over that time. With Passiflora particularly creating new hybrids is a war of attrition, but the satisfaction of the successes is always worth the wait. The best of these have been selected for worldwide distribution as the Riverside® hybrids.

Myles created the site Passiflora Online back in the year 2000, started the Passiflora Online Facebook Group in 2007 and is editor of the free to download Passiflora Online Journal.

January 2018

Plant Breeders Rights Granted (48,160) by CPVO  for the Riverside® Hybrid Passiflora ‘Snow Queen’. This has been a long slow process but we got there in the end thanks to the endeavours of PlantHaven International,inc. Picture shows breeder Myles Irvine with the ‘Snow Queen’ herself, Natalia Walaszek.

December 2017

The off season Well in a way but the work goes on. A surprising number of the more tropical species flower in December/January as flowering is triggered by shorter day length. Pictures from 2017 of an interesting new polyploid hybrid. Unusual in that it does not open any further than this. Sleeves rolled up for a productive 2018. Only release the best!

September 2017

Royal Botanical Gardens Kew A fabulous behind the scenes visit to the nurseries at Kew catching up with both Rebecca Hilgenhof & Carlos Magdalena, author of The Plant Messiah. I saw more Passiflora than I could count and indeed many other incredible plants. A day to remember and good learning experience. Picture shows Rebecca holding a huge Passiflora macrophylla leaf. It is one of the Astrophea, which are trees rather than climbing vines.

Rebecca Hilgenhof Kew Riverside

September 2017

PlantHaven Geoff and Maureen Needham of PlantHaven International pop in for tea and cake from Carmella Patisserie. They also check out progress on adding new lines to the Riverside® Passiflora hybrid range.

Riverside PlantHaven - Needhams
Riverside Hybrids Test

August 2017

Plantarium Trade Fair. The Riverside® Hybrids Passiflora ‘Damsel’s DelightPassiflora ‘Snow Queen’ have been added to the prizewinning FleuraTerraza range by Dutch climber specialists Van der Starre. FleuraTerrazza includes a range of climbers selected to ensure they will bloom in spring, summer and after summer.

Riverside Passiflora Damsel's Delight FleuroTerraza
Riverside Passiflora Snow Queen FleuroTerraza

June 2017

Horticultural Trade Association National Plant Show. Riverside Hybrid® Passiflora ‘Snow Queen’ wins HTA National Plant Show 2017 Shrubs and Climbers Gold Award and best in category – Presented by Newy PPL

Riverside Passiflora Snow Queen HTA Gold Medal
Riverside Passiflora Snow Queen HTA Gold Medal Newey

‘Pure Passion’ Plant Profile

on Myles Irvine, Riverside® Passiflora breeder, by Philip Clayton
The Garden (RHS) Volume 135 Part 9 September 2010
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Pure Passion RHS The Garden

Investigation of Passiflora hybrids using flow cytometry

L.A. King and M.S. Irvine
Passiflora (2010), 20(1):pp. 5-11
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Passiflora hybrid cytometry

‘Breeding hardy Passiflora by Myles Irvine, Riverside® Passiflora breeder.

The Plantsman (RHS) New Series Volume 9 Part 3 September 2010
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Passiflora RHS PLantsman

Passiflora Online Journal ISSN 2046-8180.

Ten issues to date, articles by academics and enthusiasts worldwide. Fabulous photo galleries. Publisher and Editor Myles Irvine, Riverside® Passiflora breeder.
Download issues here

Passiflora Online Journal

The history of Passion flower hybrids

The earliest known Passion flower hybrids were created in the early 19th century. Since that time hundreds of hybrids of these fabulous flowers have been created, of which sadly many have been lost over the years. Few are hardy however and fewer still are polyploid, Polyploidy means having more than the usual two sets of paired chromosomes. It is one of Nature’s ways of speedily adapting to environmental change. Our advanced breeding techniques are now starting to produce polyploid Passion flowers with three or even four sets of chromosomes per cell. This gives easy to care for plants with increased vigour and larger, stronger flowers which often stay open for several days.

Riverside® Hybrids have the following advantages for both nurseries and home gardeners:-

Free flowering

All the selected Riverside® hybrids are free-flowering, producing flowers at every node over a period of many months, often May-November.

Riverside free flowering


The solidity of the striking polyploid flowers lends itself to more intense colours that stand out strongly against other plants around them.

Riverside striking colours

Size matters

All Riverside® Hybrids compare favourably with Passiflora caerulea, producing bigger, stronger longer lasting flowers.

Riverside size advantage


Hardiness is approximate but these should survive occasional dips down to -8°C, 18°F or USDA zone 8b.

Riverside hardy hybrids