The Seals of Solomon

Solomon’s Seals comprise several genera of woody perennials, but the common name is most commonly associated with the genus, Polygonatum in the Asparagus family. It seems hard to imagine, but the Asparagus family now includes many popular garden plants including its namesake Asaparagus, but also hosta, agave, liriope, ruscus, and yucca.

The genus Polygonatum is native through much of the world, although the center of distribution is in Asia. We’ve been collecting these amazing woodland perennials for years, and now have a collection of over 380 different taxa. Here are a few from this week in the garden.

Polygonatum mengtzense is a dwarf, rarely cultivated species from North Vietnam.

Polygonatum mengtzense BSWJ11691

The dwarf, glossy-leaf Chinese Polygonatum nodosum just oozes elegance.

Polygonatum nodosum

When you run out of species to grow, you start creating hybrids. This is our new selection of a cross of the giant Polygonatum martinii and the more compact, Polygonatum falcatum. We’ve named this clone Polygonatum x marcatum ‘Winsome Wonder’

Polygantum x marcatum ‘Wisome Wonder’

Polygonatum odoratum ‘Chanticleer’ is a superb, large-leaf form of the Asian Polygonatum odoratum that I spied at Chanticleer Gardens, and they kindly shared in 2006. Hopefully, we’ll finally have enough to share next year.

Polygonatum odoratum ‘Chanticleer’

Polygonatum odoratum ‘Angel Wings’ (aka: ‘Carlisle) is a superb form of Polygonatum odoratum from Massachusetts plantsman, Roy Herold. This gem grows in both half day sun as well as shade.

Polygonatum odoratum ‘Angel Wings’ (aka: Carlisle)

Hi Jacks

Over the last few weeks, I’ve been working on a plant survey of a local woodland area of about 30 acres. The low, moist areas are filled with Arisaema triphyllum, (Jack-in-the-pulpit) which is quite common in our area. The first image is what is typical for the species.

Arisaema triphyllum Wake County, NC

I’ve been studying patches of Jack-in-the-pulpit for well over 55 years, always looking for unusual leaf forms that showed any type of patterning. Until last month, I’d never found a single form with atypical foliage. That all changed with my first trip to this local site, where so far, I have found several dozen forms with silver leaf vein patterns. Up until now, there are only two pattern leaf forms of Arisaema triphyllum in cultivation, Arisaema ‘Mrs. French’ and Arisaema ‘Starburst’.

Each patterned leaf clone varies slightly as you would expect within a population including both green and purple stalk coloration.

Arisaema triphyllum silver veined clone
Arisaema triphyllum silver veined clone with green stems
Arisaema triphyllum silver veined clone with purple stems

While I’d never found any true variegation prior to this, I had found plenty of transient leaf patterning caused by Jack-in-the-pulpit rust (Uromyces ari triphylli). This site was no exception, with a number of plants showing the characteristic patterning. If you find these, turn the leaf upside down and you’ll see the small orange rust pustules.

While these may seem exciting, the pattern are not genetic and will disappear without the fungus. Fortunately, this rust can be cured by cutting off the top of the plant and discarding it where the spores can not spread via the wind. Infected plant should be fine, albeit smaller next year. The susceptibility of Arisaema triphyllum to jack-in-the-pulpit rust varies with genetics. Of the tens of thousands of plants I observed at the site, less than 10% were infected with the rust.

Arisaema triphyllum with rust induced pattern
Arisaema triphyllum rust induced pattern on leaf back

Arum world

Arum are a fascinating genus of hardy aroids, known by most gardeners from a single southern European species, Arum italicum. The most popular cultivar of Arum italicum is Arum ‘Marmoratum’. The key to enjoying arums is to not let the seed drop everywhere, since you can get easily get over-arumed. Flowering season is now, followed by seed season. Each seedling has a different pattern from the original, so it’s a personal preference whether to remove seed or not.

Arum italicum ‘Marmoratum’

Arum apulum is a little-know species that is rarely seen in cultivation, native only to a small region of Southern Italy. Our flowering plants in the garden now are from a wild collection made by a plant explorer friend.

Arum apulum

Below is an interesting hybrid between Arum italicum (central to southern continental Europe) and Arum dioscorides (Mediterranean). Arum italicum has patterned leaves, but solid green flowers. Arum dioscoridis has solid green leaves and spotted flowers. The hybrid, Arum ‘Chui’ is an introduction from UK plantsman John Grimshaw. We added the notospecific (hybrid) name Arum x diotalicum. These hybrids have both spotted/speckled leaves and flowers.

Arum x diotalicum

Japanese Princess Sedge

Carex conica ‘Hime’ has been in horticultural commerce for many decades, and remains a superb woodland garden sedge. The evergreen species Carex conica is native throughout Japan, where it occurs in woodland conditions. This variegated selection that goes by an array of names such as ‘Snowline’ and ‘Marginata’, but Carex conica ‘Hime’, which translates to “princess” seems to the the correct cultivar name. The tight 10″ tall x 20″ wide clumps of narrow white-edged leaves are topped with this fascinating floral show for us in early March. In 35 years of growing this, we have yet to see a single garden seedling.

Striking Gold

Trillium cuneatum ‘Oconee Gold’ is a rare gold-flowered selection of the typically purple-flowered southeastern toadshade. We found our original plant of this in Oconee County, SC, and have propagated them from seed since that time. If we keep the yellow-flowered plants isolated from purple-flowering clones, we have more than 50% that reproduce with yellow flowers. The time from seed to flower is usually five years. Winter hardiness is Zone 5a-8b.

Streaked like a Comet

We treasure any plant that makes a great woodland groundcover, and are particularly smitten with the ophiopgon (mondo grass) and liriope (monkey grass) selections. We currently grow over 120 different ophiopogon accesions including quite a number of wild collections, at JLBG…see what a touch of OCD does for you. We’ve grown Ophiopogon ‘Comet’ since 1997, and love it for its white striped foliage and well-behaved growth habit. Hardiness is Zone 7b-10b.

Cyclamen and Cyclawomen

Here are a couple of images this week from the garden of our older clumps of Cyclamen hederifolium. For garden areas that are dark and dry, where nothing else grows, cyclamen are your best bet. Of the plants below, one is at the base of a cryptomeria and the other at the base of a pine. Although they flower from August until Christmas, the winter foliage is just hard to beat. Hardiness is Zone 4a-8b.

Artist’s Palette in Winter

Asarum hypogynum ‘Artist’s Palette’ is in full flower here at JLBG in late January. Despite being first published in 1915, this little-known species is very poorly represented in ex-situ plant collections worldwide. Our clone is a division from a wild plant we brought back from our 2008 botanical expedition to Taiwan. The foliage on this species is some of the largest in the entire genus. For us, Asarum hypogynum starts flowering in late summer and continues most of the winter. We are working to eventually be able to share this with other collectors. Hardiness is Zone 7b and warmer.

Asarum hypogynum ‘Artist’s Palette’
Asarum hypogynum ‘Artist’s Palette’

A Major Minus

Asarum minus ‘Cupid’ is one of our heavily silver patterned selections of our native wild ginger. When cold weather arrives, the evergreen leaves take on a lovely purple cast. This is an excellent clonal selection we made in 1994 from a construction site, and one we hope to offer in the future though Plant Delights Nursery.

Stingray in the Garden

One of our favorite winter hardy (Zone 7b) century plants is the non-spiny Agave bracteosa ‘Stingray’. Here is one of our garden specimens this week, which has been thriving in the ground since 2016. Unlike most agaves, which prefer full sun, Agave bracteosa is better in part sun (full sun for only a few hours during the day). Agave bracteosa ‘Stingray’ is also a fairly slow grower that only produces a few offsets. A mature rosette will top out around 15-18″ tall x 2′ wide. We love the unique texture, which differs from all other agaves.

Hot Legs

Bambusa multiplex ‘Alphonse Karr’ is looking so hot this winter with its amazingly striped canes. This clumping bamboo is usually grown as a die-back perennial here in Zone 7b, since it goes to the ground when temperatures drop below 10 degrees F. Because we’ve had three mild winters, we are once again able to enjoy the amazing striping of the canes. I did get a chuckle last year, when I saw Bambusa multiplex show up on an invasive species list for North Carolina. As I explained in my letter to the group, Bambusa multiplex is first and foremost, a clumping species. Secondly, all truly invasive species (which invade functioning natural ecosystems, displacing natives and causing economic harm once population equilibrium has been reached) must be able to spread by seed, and bamboo clones only flower once in 100 years, and then die. It’s these emotionally driven lists, without any basis in facts or real science, that makes so many of the invasive lists a farce, and sadly untrustworthy.