A Gardening Journal

Today in the Garden of a Lifetime: The Curtain of Hardy Passion Vine

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Summer through frost, this hardy passion vine is showstopping. Stems hoist themselves upward to about ten feet, via coiling tendrils just like those of grapevines. The unusual foliage is striking all alone, but when hundreds of flowers open, they take the focus.

 

This season, Passiflora lutea and I collaborated to make the show even better. I supplied plenty of verticals of twine for the stems to race up, enabling the vine to form a lacy curtain of growth about eight feet square, barely a foot out from the south wall of the house.  The display is as stunning when seen with the house as the backdrop as when seen from the interior, through a convenient window. It's the garden's best Passiflora performance ever.

 

In the picture below, one of the many pendulous racemes of flowers has formed directly in front of the window. The tiny, creamy-green buds open to still-tiny flowers, which are highlighted beautifully by the comparative darkness of the house's interior.  

 

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The flowers are barely as big as my thumbnail. Even in miniature, the complex floral structure so typical of passion vines is exuberantly displayed. The ruff of long creamy tendrils, known as a corona, is right above the ring of five petals alternating with five sepals. The central columnar structure that bears the male and female parts is called the the androgynophore; the Latin word translates as the bearer (the "phore") of the male ("andro") and female ("gyno") parts. Around the base of the androgynophore are several concentric rings of vertical filaments. The outer rank is light brown, the inner ranks are nearly white. These rings form the operculum, which protects the nectar-bearing glands of the flowers that are hidden deep in the center, around the base of the androgynophore.  

 

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The picture below shows the flower in close-up. At the top of the androgynophore is the candelabra-like array male and female parts: a star of five pollen-bearing stamens topped by a trio of receptive pistils.

 

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How the geometry of five-versus-three is determined by the growing plant is a mystery. Each of the five stamens is equally spaced from its brethren, with 72 degrees between them out of the possible 360 degrees of a full circle. Each of the three pistils is equally spaced from its brethren, with 120 degrees between them out of the possible 360. But no simple relation between the two spacings is possible: the ratio of 120 to 72 is 1.6666666666 to infinity.  

 

Even so, the relative spacing of pistils to stamens is always maintained. Pistils are between stamens—however approximately—not on top of them.

 

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The best view of the curtain of growth is from within the house, with the south sun streaming through the Passiflora foliage.

 

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Here's how to grow this hardy passion vine. Here's how this hardy passion vine looks in the years when it can scramble through the titanic foliage of a nearby colony of ricepaper plant, Tetrapanax papyrifer.

 
 
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