A Gardening Journal

Hardy Passion Vine

Published: July 28 2011

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Passion Vine flowers:  The Mr. Potato Heads of the plant world:  Too many parts, each sillier than the next.  At the very top, the waving pistils, each in quest of pollen.  (Usually there are three of them, but this flower has four.)  Below them, a merry-go-round of stamens, each head a little yellow boat of pollen nuzzling its partner both fore and aft.  There are five of them.

 

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At the base, the "corona" of long filaments, colorful and kinky in all senses.  Somewhere down in the middle of the corona, at the base of the little tree that holds the stamens and pistils, the nectar.  Visiting pollinators—bees, hummingbirds, butterflies—sidle up for a sip, brushing up against the pollen superstructure.  Lastly, the flat disk of lavender petals. 

 

It's a unique stack-up of cool stuff.  Who can resist having a passion vine in the garden—especially as there are a few that are hardy north to Boston?  This one is the easiest:  Passiflora incarnata.  If you get it established (see the How to Handle it, below), you'll have it forever.

 

The large three-lobed foliage is distinctive in its own right, so you have a show even before the crazy flowers start.

 

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Here's how to grow this hardy twining vine:

 

Latin Name

Passiflora incarnata

Common Name

Maypop; hardy passion vine

Family

Passifloraceae, the Passion Vine family.

What kind of plant is it?

Hardy self-clinging vine, herbaceous in Zone 6 and 7.

Hardiness

Zones 6 - 9.

Habit

Self-clinging by grape-vine-like tendrils, this multi-stemmed vine sprouts each Spring from surprisingly wide-spreading underground roots.

Rate of Growth

Fast.

Size in ten years

Depending on how it's trained as well as controlled, a colony fifteen feet tall and ten feet wide—or coverage for your entire back-yard fence.  Or your entire back-yard.

Texture

In rich soil and in hot climates, potentially a dense smothering mass atop anything in its way.  In Zone 6 and the colder portions of Zone 7, wide-spaced sprouts garland but don't obscure nearby shrubbery, fences, or even garden furniture that wasn't moved out of reach that week.

Grown for

its rarity in lower Zone 7 and anywhere in Zone 6:  So many passion vines are subtropical and tropical that the (few, admittedly) ones that are hardy north of the Mason Dixon Line are a true surprise.

 

its distinctive passion-vine flowers, with various lavender and white parts in a typically complex array of petals, then a "corona" of thin filaments as wide or even wider than the petals, then the peculiar and distinctive "architectural" central structure of pistils and stamens unique to passion vines.  

 

its fruit, which is tasty, if full of seeds.  It's also the larval food for various butterflies, and is favored by wildlife in general.

Flowering season

Summer: July into September in Rhode Island.

Culture

Sun, heat, and any decent soil. 

How to handle it

In Zone 7 and up, Maypop can be prevalent to the point of weediness, but, on the other hand, is a quick way to hide chain-link fence, outbuildings, and slow-moving neighbors. 

 

In Zone 6 and the north portions of Zone 7, establish by planting in Spring where the plant gets all possible sun and heat, and where the roots are protected, especially the first Winter or two, from wet and cold.  Plant right by your house's foundation so the roof overhang reduces direct Winter precipitation (but, yes, also reduces it in Summer, so you'll need to water your plant weekly while it's establishing).  Mulch heavily the first few Winters. 

 

Remove the mulch in early Spring so the sun can warm the soil and encourage the roots to sprout.  Be patient: Maypop is very slow to get started; I don't see sprouts until June.  You'll know you've been successful at establishment when you're surprised by sprouts that are several feet (or even yards) away from where the plant is "supposed" to be.  Indeed, a well-established plant is just as likely to disappear from where you planted it as pop up eight feet away in any direction. 

 

From now on your challenge is control, not coddling.  Yank out or clip off any sprouts that are out of bounds; you can also "redrape" stems that have tendriled themselves less advantageously than you'd like.  Gently pull them free, cutting through any uncooperative tendrils along the way, and then rearrange.  Stems grow (and therefore keep blooming) for most of the season, so their new tendrils will quickly attach and hold the new configuration you've chosen.

 

It would be heaven if you were able to grow Maypop in a narrow bed between a concrete walkway and a broad and tall south-facing brick wall.  The walkway would control (somewhat) the outward spread of the roots, and the wall would provide additional Summer heat as well as Winter shelter and dryness; passion vines enjoy growing near masonry.  Walls in general set them off very handsomely and also bring their complex and sometimes fragrant flowers into prime viewing and sniffing range.

Downsides

Maypop can be hard to control in hotter climates, spreading both by the underground roots and by the seed spread by its many eager animal consumers. 

Variants

There are over 500 species of passion vine as well as scores of cultivars and hybrids.  Most are tropical, where there are tree- and shrub-sized species, too, not just the vining species that typify the family.  Mature growth can range from a few feet long to many many yards.  The remarkable flowers can be white, yellow, pink, blue, orange, or scarlet, and in many bi-color combinations, too.  The fruit can be showy as well as edible. 

 

In favored climates passifloras can cover tedious garages in a year or two, big pergolas ditto, and bloom with hundreds of ultra-showy flowers for months on end.  In harsher climates there are still many candidates to grow in containers (both pots and hanging baskets), as throw-away Summer annuals, or as permanent house-plants.

 

Although none is hardy into Zone 4, P. lutea is rated Zone 5, with somewhat "bat-wing" leaves and small yellow flowers.  P. 'Incense' has particularly deep-violet flowers and excellent Zone 6 hardiness, and P. 'Constance Elliott' has pure white flowers and reasonable Zone 6 hardiness.  (That said, I've failed twice to establish 'Constance' here in Rhode Island.  Next Spring, Round Three.)

Availability

On-line.

Propagation

By division in Spring; the species by seed.

Native habitat

P. incarnata is native to the United States, from the lower Midwest and Central Atlantic to the Gulf Coast and Florida.