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

Variegated Pennywort

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Variegated pennywort loves to spill from containers that are kept moist.  As long as you keep the pot in a deep saucer of water, pennywort will fluff up, out, and down in a graceful cascade.  'Crystal Confetti' has variegated leaves, so makes the brightest show. 

 

I keep a pot of it sitting on a stone slab, so there's even more room for its cascade.

 

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At the back, a huge old pot of 'Gloire de Marengo' ivy that I staked up many years ago.  The main stem is now so thick that it's a self-supporting trunk.

 

hydrocotyle-sibthorpioides-crystal-confetti-hedera-640

 

With the dark green of the yew hedge behind, this pair of warm-weather containers shows up well even from a distance.

 

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By now, both the ivy and the Hydrocotyle are overwintering in shelter.  The ivy goes into the greenhouse, and the Hydrocotyle, which light frost can convince to die back to the ground, sits in the basement.  Next Summer, I'll add a pot of elephant ears, whose huge and light-green leaves will contrast equally well with the Hydrocotyle cascade below and the "tree" of ivy above.

 

 

Here's how to grow this easy—almost too easy—moisture lover:


Latin Name

Hydrocotyle sibthorpioides 'Crystal Confetti'

Common Name

Variegated Pennywort

Family

Apiaceae, the Carrot family.

What kind of plant is it?

Herbaceous perennial

Hardiness

Zones 6, with protection, to 11

Habit

Prostrate and wide-spreading.  Above water and on "dry" ground that doesn't, in fact, get dry, it's a fluffy mound of scalloped-edge round foliage, cascading where it can and spreading out horizontally when it can't.  Also happy as a fully-submerged aquatic, in which case the stems float upward.

Rate of Growth

Fast.

Size in ten years

Spread is dependent on congenial habitat.  Pennywort can spread so far and so fast that it can be used as a warm-weather annual.  Where hardy, but only where there's enough water, it can become a troublesome weed.  In a contained water garden isolated from native waterways, and without herbaceous foragers, full surface coverage could be possible. 

Texture

On moist ground or at the surface of water: Low and lively, with loose but dense growth.  This is one of the best ways to tell variegated pennywort apart from creeping charlie, Glechoma hederaceae 'Variegata', whose leaves are of similar size and markings, but are held very close to the stem, with almost no petiole.  Glechoma forms a much tighter carpet and a much more narrowly-vertical cascade.  Glechoma is also not nearly as moisture-tolerant. 

 

When Hydrocotyle is growing fully submerged:  Upright and delicate, its long thin stems are so buoyant they're vertical.  There's a length of clear stem between leaves, so the habit is conspicuously open and graceful.

Grown for

its foliage: The round leaves are irregularly sectioned and bordered with white, so much so that the plant is as lively at a distance as it is up close.  The leaves are on long petioles, and alternate widely along thin green trailing stems.   

 

its habit: Pennywort is low and wide-spreading atop still water, but will also grow in water that cascades.  The plant will cascade a foot or two over the lip of containers—down into the air, in other words—making a curtain of green wiry stems spangled only occasionally with leaves.

 

its flexibility:  Pennywort grows fast enough to be used as a warm-weather annual in containers, not just as a year-round perennial.  Evergreen and evergrowing in frost-free climates, it's deciduous with light frost, and dies back to the ground when temperatures fall much into the twenties.  It's supposedly hardy, with protection, into Zone 6.  It can be grown "terrestrially"—in regular garden soil—as well as in pots that are sitting in water or just barely submerged in it.  It also thrives as a fully-submerged aquatic, planted in the bottom of ponds or aquariums. 

Flowering season

Year-round in mild climates.  The flowers are not showy.

Color combinations

Hydrocotyle sibthorpioides 'Crystal Confetti' goes with everything.

Partner plants

Hydrocotyle is an exciting fluffy groundcover at the feet of plants that are large-leaved as well as narrow at the ground, so they don't provide a handhold for Hydrocotyle to scramble upward.  Hostas, caladiums, and elephant ears are all good candidates, who all share pennywort's preference for rich and moist soil.  Unlike elephant ears in the Alocasia or Xanthosoma genuses, Colocasia cultivars and species thrive in the same bog-like conditions that Hydrocotyle prefers, so would be particularly compatible.  But any conditions moist enough for eager elephant ear growth would also be good enough for Hydrocotyle.

Where to use it in your garden

Hydrocotyle can grow thickly enough to work as a groundcover, but I think it's best as a container plant partnered with other moisture-lovers.

Culture

Sun and moist soil; easiest when grown as an aquatic.  Hydrocotyle can grow in regular beds provided the soil is rich and doesn't dry out.  It can even compete with lawn, at least where the lawn is already thin from lower light and too much moisture.

How to handle it: The Basics

Hydrocotyle looks great cascading out of containers, but only when they don't dry out.  Set pots of Hydrocotyle in deep saucers, then, and keep them full of water.   

How to handle it: Another option—or two?

Pots of Hydrocotyle can be set out in a water garden so the floating growth can form a fluffy carpet across the water's surface.  Hydrocotyle will also grow fully-submerged, but is only showy when seen from the side, as in an aquarium

Quirks or special cases

You can overwinter pots of Hydrocotyle by bringing them indoors and keeping them moist and warm in a sunny window.  Or let the pots become lightly frosted, which will force the Hydrocotyle to die back to the ground and become dormant.  Then the pot will sit happily in a cool, dark, and humid spot the entire winter.  Don't let the pot dry out, though, so if overwintering space has low humidity, check once a month and water as needed. 

Downsides

Hydrocotyle sibthorpioides is difficult to control where it's hardy and where growing conditions are welcoming.  It spreads rapidly and can resprout from even small pieces left after weeding.  Seeds germinate easily, too.  Where it's hardy, this is a plant for indoor aquariums and contained water gardens, not for use in the garden.

Variants

Variegated pennywort is one of the few Hydrocotyle species welcome in ornamental gardening.  H. verticillata has upright green leaves that grow densely enough to make a charming foreground planting in aquarium "landscaping."  It's a weed in the landscape.

Availability

On-line.

Propagation

By cuttings as well as by division.  Hydrocotyle stems root as they travel, and can resprout from even the smallest piece.

Native habitat

Hydrocotyle sibthorpioides is native to southeastern Asia.

 
 
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