If you’ve visited PDN/JLBG this year, you’ve no doubt noticed the construction of the new Raleigh outer loop, I-540, which required the seizure of nearly an acre of our property. The construction also requires our road to be raised 15′ to clear the new Interstate being built below grade. This will add a whole new level of adventure in the winter when the road is covered in snow or ice. This week, the new Sauls Road overpass will be completed. While there will not be an exit on Sauls Road, there will be one within a mile both east and west of the gardens/nursery. Construction of the new Raleigh southern loop is scheduled to be completed in late 2023.
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
Wednesday, March 23, 2022 is the NC State University Day of Giving…a time for those who want to support activities at NC State. In our case, that means the endowment we are building to preserve Juniper Level Botanic Gardens. If you care about ensuring the gardens remain intact for future generations, please consider making a contribution to the endowment. You can do so at this link to the University Endowment Fund for JLBG.
