Louis Raymond experiments in his own gardens like

a mad scientist, searching out plants that most people have

never seen before & figuring out how to make them perform.- The Boston Globe

…Louis Raymond ensures that trees can grow in Brooklyn…

or just about any other place where concrete consumes

the dirt and skyscrapers shield the sunshine.- USA Today

 
 

NEW Trips to Take!

Myrtle's easy when the conditions are right.

 
 
 
 

NEW Plants to Try!

Louis tries to capture the exact words to describe the fleeting but deep pleasures to be found in these Summer-into-Autumn incredibles.

 
 
 
 

New Gardening to Do!

Allergic to bees? You can still have an exciting garden, full of flowers and color and wildlife.

 
 
 
 

Plant Profiles

Hardy Yellow Passion Vine

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Passion-vine flowers that are only an inch wide are, nonetheless, still the real deal.  And because so few passion vines are hardy at all, it's a blessing to have one you can grow even in Boston, not just in Boca.

 

Passiflora lutea is such a Lilliputian that, even though it's native to the entire eastern seaboard, you may have passed hundreds in the woods and yet never noticed any of them.  I call attention to its minuteness—minutity?—by growing it near some stems of rice-paper plant, Tetrapanax papyrifera.  Just one of its immense leaves is bigger than the entire Passiflora vine. 

 

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The flat Tetapanax leaves are a great "platter" on which the delicate Passiflora growth can preen.  True, it still helps to have low-power magnification handy.

 

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Here's how cool this passion vine looked when it could climb through the high growth of Chinese ricepaper plant, Tetrapanax papyrifer. Here's how the vine grew even more vigorously, when I provided vertical lines of twine, and guided young stems to them in late Spring. 

 

Here's how to grow this dainty native vine:

 

Latin Name

Passiflora lutea

Common Name

Hardy Yellow Passion Vine

Family

Passifloraceae, the Passion Vine family.

What kind of plant is it?

Hardy vine.

Hardiness

Zones 5 - 10.

Habit

Scrambling, self-clinging vine. Herbaceous at the colder end of its hardiness range.

Rate of Growth

Medium.

Size in ten years

Size depends on the circumstances. In Zones 5 - 6, modest growth to 3 - 5 feet; potentially two and even three times that in Zones 7 - 10. With full sun and maximally protected siting in my garden in southern New England—just barely Zone 7—stems have twined to twelve feet tall and eight feet high. in 2015, I'm going to extend the climbing opportunity even higher, in hopes that the vines can race up to the roofline.

Texture

Variable: For years here in Zone 6 - 7, this plant was strictly a scattered (but exciting) swagging amid its neighbors. But the colony has only picked up steam, and is thicker and larger than ever despite last season's unusually severe Winter. Now the colony forms a dense curtain of foliage, spangled for months with the tiny yellow flowers. See "How to handle it" and more recent posts for one way to encourage growth that is more extensive as well as denser.

Grown for

its rarity: Only a few of the dozens of Passiflora species and hybrids are hardy below Zone 7, P. lutea is unique in being hardy all the way into Zone 5. Although native up and down the eastern seaboard, P. lutea is all too infrequently seen in gardens.     

 

its foliage: P. lutea leaves are wider than long, gently curved into three lobes.

 

its stems, buds, and tendrils: These "accessory parts" are all a lighter color than the foliage, and the contrast enhances the display of foliage and "parts" alike.

 

its flowers: They may only be an inch wide on a good day, but the pale green-yellow flowers still have passion flowers' classic and complex "cakestand" structure of (bottom to top) calyx, petals, corona, stamens, and pistils.  The arithmetic is as odd as the geometry:  There are five calyx "petals," which are known as sepals, as well as five true petals and five stamens, but only three pistils.  (The filaments in the corona are too numerous to count without magnification.) 

Flowering season

August into October:  Late Summer, just when you need it.

Culture

Full sun or part shade, good soil, average to good amount of water.

How to handle it

Compared to other hardy passion vines, such as Maypop, P. lutea is modesty personified. Just a few stems emerge late in the Spring to explore adjacent perennials and shrubbery. I usually don't discover that the plant is alive until a tendril finally swags into full sight atop an adjacent perennial's leaf that may be only two feet high. It's the opposite of the yard-after-yard rampantness of Maypop. So plant P. lutea where you'll remember its location (a permanent little marker will be a help), and keep an eye out for it.

 

One way to encourage larger and thicker growth is to give the young stems easy opportunity to climb. My colony has doubled in bulk as well as height when I provided vertical lines of twine extenting upward nine feet—and then I guided young stems to each of them in late Spring, so their prehensile tendrils could quickly grab hold. If I attach these lines of twine much higher up next Spring—at the gutter line of the house, which is two stories tall—will the vines just race all the way up? Perhaps the ultimate height of this species as less a matter of climate than of climbing opportunity. 

 

The usual "good drainage in the Winter" mantra applies, especially in Zones 6 and 5, where planting near your house's foundation, or in the protection of nearby evergreens or boulders, can also help enhance Winter survival as well as vigor.  Remember that this isn't a drought-tolerant plant, though, so if planting near larger evergreens, be sure the plant isn't stuck back under the canopy, where it will normally be too dry.  

 

The little tendrils seem better at tangling one stem of the plant to another instead of anchoring the plant to its neighbors. For me, P. lutea is a plant that looks best when you commit to periodically (re-)arranging it across the bosom of adjacent plants, as you would a colorful scarf or cool jewelry.

 

Don't worry about Fall clean-up: The few and thin vining stems won't show in Winter anyway and, come Spring, will also help remind you that, yes, there really is a Passiflora lutea somewhere in the vicinity. 

Downsides

A modest vine, with Lilliputian flowers, isn't the plant for where you'd like a strong statement. When your garden already has the "big show" you want, then you're ready to welcome some intriguing subtleties like P. lutea.

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, and some (but not all) are 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 to 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', with 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 seed, cuttings, and by division in Spring.

Native habitat

Passiflora lutea is native to the East Coast of the United States, from Maine through Florida.

 
 
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