The Monkey’s Puzzle

Norfolk Island Pines (Araucaria heterophylla) are popular house plants, but we always longed for being able to grow araucarias outdoors in central NC. Since this native of the region around Australia/New Zealand has poor winter hardiness, our obsession focused in on the more winter hardy, South American species, in particular, Araucaria araucana, known as Monkey Puzzle tree. This species hails from the mountains of Chile, where they thrive with little or no rain in the summer months, when growth is at its peak. While they are completely winter hardy into warmer Zone 6, they have no tolerance for rain in the summer months. We once got one to 7′ tall, but it died in less than 1 hour during a summer rain storm.

Now that we’re officially in Zone 8a, we can probably get the Brazilian native, Araucaria angustifolia to survive. We had this for several years in the early 2000s, but lost our 15′ tall specimen in 2004 after a cold winter. The photo below is a thriving specimen I visited last week in conifer collector Scott Antrim’s garden near Charlotte.

The key to success in our climate would be to have a hybrid between the two species. This would offer the improved cold hardiness of Araucaria araucana, with the summer moisture tolerance of Araucaria angustifolia. In fact, such a hybrid exists. In 2010, Plant Delights offered the hybrid, and all of the 55 plants we had to share sold quickly. We kept one here at JLBG and one went to our sister institution, the JC Raulston Arboretum (see below). Both plants are thriving, but what we didn’t realize at the time was they it takes two plants to have meaningful sex. Both the Raulston plant and our plant produces cones each year, but neither contain viable seed.

Without any way to procure more hybrids, we’re trying the next best thing, which is planting more of both parents near our hybrid, in the hopes that it will grow and pollinate our hybrid. We’re hoping that by planting a new Araucaria araucana seedling underneath our hybrid, it will remain dry enough even during summer rains to survive. Our new Araucaria angustifolia is still a bit small, so we’ll wait until next year to put it in the ground. Hopefully, within a decade, we’ll have viable seed. Wish us luck.