While most arisaemas flower in early spring, several members of the Franchetiana section of the genus are summer bloomers. There are five species in this section, but the only one that flowers in spring is Arisaema fargesii. Flowering recently are those pictured below, A. candidissumum, Arisaema franchetianum, and Arisaema purpureogaleatum. The debate still rages on whether Arisaema purpureogaleatum is merely a form of Arisaema franchetianum, but regardless, it has a distinct appearance when in flower. Of these three, Arisaema candidissimum is the least tolerant of our summer heat.
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.
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.
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.
Flowering at JLBG since early March is the little-known Jack-in-the-pulpit, Arisaema ilanense. This collection hails from Ilan (Yilan), in northeastern Taiwan, and for us is the very first arisaema to flower each winter, even when temperatures are still quite cold. The mature size is only 4-6″ in height, so this is one for a very special site in the rock garden. There are very few plants of this species in ex-situ conservation collections, so thanks to JCRA Director, Mark Weathington for sharing. Our specimen has been in the garden since 2016. Hardiness is unknown, but we’re guessing Zone 7b-9b.
For two decades, we’ve grown the amazing Chinese jack-in-the-pulpit, Arisaema saxatile with its delightful lemon-fragranced flowers. The most frustrating part was its slow offsetting nature, which meant we rarely had any to share.
Eighteen months ago, we dug our main clump and moved most of it from a well-shaded site to a location that would get a couple of hours of afternoon sun. To our surprise, it loved the new site, where this summer, it produced two large seed heads which will be harvested shortly. This is the first sign of seed in 20 years, so hopefully in a few years, we have some good numbers to share.
After being told several years ago that creating interspecific hybrids of arisaema (Jack-in-the-Pulpit) was virtually impossible, we started our own breeding program. Here are a few of our creations from our Contrarian Frankestein Lab that are looking quite nice this week.
The Japanese Arisaema sikokianum (Jack-in-the-pulpit) posing with Hosta ‘Kabitan in this glamour shot.