Arizona Expedition Log
12/12/04 - 12/18/04
Plant Delights Nursery, Inc.
9241 Sauls Road
Raleigh, NC 27603
Shop for Perennials at Plant Delights Nursery
Participants: Tony Avent, Plant Delights Nursery
Why Arizona? Surprisingly, there are quite a few plants from the desert southwest that thrive in piedmont North Carolina. Arizona is a fascinating state with climates that range from USDA Zones 5a-10a. The vegetation ranges from desert regions to coniferous forests. Some species such as Adiantum capillus-veneris and Smilacina racemosa are native to both NC and Arizona. There has been surprisingly little horticultural work done to evaluate natives of this region for adaptation around the country. Have you ever grown Polygonatum cobraense or Cimicifuga arizonica? I didn't think so. We look forward to studying, obtaining, and trialing many of these wonderful southwest native plants for their adaptation to gardens in other climates.
In December 2003, I made by first botanical trek to Arizona. My goal was to focus on two groups of plants: sun-tolerant desert ferns and agaves. This was the first of four trips in eight months that would take me to study the top agave collections in the world: Desert Botanic Garden in AZ, Huntington Botanic Gardens in CA, the Ruth Bancroft Garden in CA, the Berkeley Botanic Garden in CA, and the Jan van Roosbroeck Garden in Belgium. Starting with a day at the Desert Botanic Garden accompanied by garden writer Mary Irish (former DBG curator), my trip also included a second day trip with Mary and Gary Irish to the Boyce Thompson Arboretum, and one solo day in the mountains of the Tonto National Forest. The trip into the mountains just whetted my appetite for a return trip, despite having to navigate a frightening ice cap on the road at over 7,000' and a car that had just slid off the side of the mountain.
This being my second botanizing trip in 2 years to Arizona, I chose to spend the first day at the Desert Botanic Garden herbarium. For those who aren't botanically inclined, a herbarium is essentially a plant mausoleum. Plants are killed, identified, their original location recorded, then they are glued to sheets of paper and stored in a climate- controlled overhead vault. I arrived at the herbarium in the morning and met with Dixie Damrel, Assistant Curator of the Herbarium, who showed me how their herbarium was organized. Most of the day was spent in the fern cabinet, since my main area of study was desert sun ferns. I isolated one prime area of interest, the Tonto National Forest just east of Phoenix. In fall 2003, I had spent one day in the Tonto National Forest (north on Hwy 87 and back south on Hwy 188) and was eager to return.
Later that evening, we met up again with good friends (and delightful folks), Mary and Gary Irish, authors of Agaves, Yuccas, and related Plants. We had sent them a few sacrificial plants earlier in the year for desert testing, so it was a great opportunity to check on their progress. Our native Yucca gloriosa looked good, but Yucca filamentosa had not thrived. As I had hoped, Hymenocallis eucharidifolia looked right at home. After a quick run through their wonderful garden, it was off to dinner and plant chat. Mary had just completed her newest book about Southwest Perennials, for Timber Press the night before, so the evening made for a nice celebration.
Day 2, I returned to Desert Botanic Garden to study their extensive agave collection...the largest outdoor collection after the Huntington Botanic Garden in California. I was accompanied by Chad Davis, curator of Agaves.
Mary and I had discussed earlier sorting out the various different clones of yellow-margined Agave americana. Mary has isolated at least 4 different clones, but Chad and I were only able to identify three at the garden. It is our hope to work to sort these out, giving valid cultivar names to distinguish the different forms.
It's hard to know where to start talking about plants in their wonderful collection, but several caught my eye. There were several clones of the rare Agave arizonica, now determined to be a hybrid of A. chrysantha. I also spent quite a bit of time studying Agave funkiana. This species is probably just a form of A. lophantha, which means it will probably grow well in our climate. One clone in particular had rosettes that were over 5' wide. Agave lechuguilla is another easy-to-grow species that is often dismissed as ugly. Indeed, my West Texas collection is not the most attractive of agaves, but several of the clones in the garden have outstanding garden merit.
An agave that I had only recently acquired was Agave glomulifera. This natural Texas hybrid of A. havardiana was quite charming. Another nice dwarf that should perform well in NC is Agave schottii var. treleasei. I look forward to trialing this one. Having grown only one clone of Agave parryi ssp. truncata, I was amazed at the Gentry collection that was very different from the commonly grown Ruth Bancroft clone.
Not only were there great agaves, but yuccas as well. The one that nearly sent me over the edge was a stunning yellow-edged form of Yucca baccata. They had two 6' tall x 6' wide clumps that were simply outstanding. A new addition to their collection was a yellow-edged Yucca schidigera. Although this baby is still in a container, it's a real stunner. Although I wasn't focused on cacti, their signature plant, a crested saguaro is a marvel of nature.
Morning arrived early and it was time to head out into the field. From Phoenix, I headed north on Hwy 87 to the town of Payson. In Payson, the vegetation changed from open desert to tall pines... an obvious sign that I had moved into a more moist and colder climate. Payson has become a development mecca thanks to it's wonderful climate and great mountaintop views from 4,000' elevation. From here, I headed east on Hwy 260 toward the town of Heber. As I headed east, snow from an early season snowfall still covered the roadside, which was adorned with an overabundance of 'Watch for Elk' road signs. Neither was not a good sign in my quest to find populations of the southern maidenhair (Adiantum capillus-veneris). Finding my proposed route south through the mountains proved more difficult than I realized. It took several backtracks until I realized that what I thought was a highway on the map was actually a dirt forest road (FR 512).
Dodging the motograders which were leveling the pock-marked road, the roadside trees grew at a reduced size as I headed south into a hotter, drier region. Only a few miles down toward the town of Young (Gila County) at 6,300' elevation, small ball cacti and agaves begin to become more prevalent. Within a few more miles (5,500' elevation), Agaves, probably A. parryi, were everywhere. There were some amazing forms, certainly worthy of making some named selections. Although seed stalks abounded, there were no seeds remaining this late in the season.
At this same elevation as the agaves became more prevalent, ferns started appearing, first the stunning blue-grey Pellaea mucronata and then the dwarf green Cheilanthes covillei, both growing nearby ball cacti. Not far away, I found a superb population of Bommeria hispida, a superb dwarf that I had collected years earlier in West Texas. At the same site was another Cheilanthes that I think to be C. fendleri. At this point (5,900' elevation), the main woody vegetation has changed to scrub junipers.
At the town of Young, the road changed names from FR512 to Hwy 288, although the road still was not paved for long stretches. One of the most unique stops along the route was the 5200' elevation crossing at Workman's Creek, about 45 miles north of Globe. Here a 8' wide rocky creek was lined with giant 60' tall sycamores. This was reportedly the site of one of the plants that I had hoped to see, Adiantum capillus-veneris. Unfortunately, winter had already arrived and the maidenhair fern was nowhere to be found. Despite being dormant, there were large patches of Disporum trachycarpum. It is one of three solomon's seals native to Arizona.
Further down the road and back into the dry desert, I stopped at a steep roadside rock outcrop that wound up as the best fern site of the day... nine ferns within a 50' x 50' site. Among the agaves, I found Pellaea wrightiana, P. mucronata, Bommeria hispida, Notholaena sinuata, Selaginella sp, Cheilanthes villosa, Cheilanthes covillei, an unidentified white-back cheilanthes, and my first sighting of the beautiful Pityrogramma triangularis.
As I headed lower into the mountain, I saw saguaro cacti starting to appear at 3500' elevation. I have been looking high elevation forms of saguaros that might be hardy back in North Carolina. One day, I must return when saguaros are in seed. By this time it was getting dark, and the Arizona mountains are not the place to be driving at night, so I departed for the 2.5 hour drive back to Phoenix.
For my second day in the field, I headed north toward the town of Prescott to visit the Prescott National Forest. Near the Yavapai County town of Mayer, I headed into the mountains on the Forest Road. Most of the forest roads are not well marked, and this was certainly the case. It look 30 minutes of driving through the town before I found that Second Avenue eventually turned into a Forest Road.
The word 'forest' in Arizona certainly has a different connotation than that of Eastern US forests. Indeed, trees were non-existent with only Berberis trifoliata, junipers, and a few other spiny shrubs dotted the landscape. At 4,700' elevation, the first rock outcrop yielded a couple of ferns that I had already seen, Pellaea mucronata and Cheilanthes covillei. The area was also littered with prickly pear opuntias in every shape and size. The most exciting thing was some very tall clones, one reaching 7' tall. Usually, the only padded opuntia that reaches this height is the tender O. ficus-indica. I estimate that this was certainly Zone 7 or maybe 6. The wind was howling at 40+ mph dropping the wind chill well below freezing.
After turning the corner and gaining some protection from the winds, I climbed higher to find huge specimens of Agave chrysantha. These mostly solitary specimens had beautiful banded leaves. Despite the numerous flower stalks, the winds had long dispersed any remaining seed. Birds had made nesting use of the old agave flower stalks, many of which last for several years. Among the agaves was also a fascinating dwarf cheilanthes, reaching only 1" tall and inhabiting rock cracks.
About 3 miles into the desert, I saw the first sign of water when I crossed a small rocky creek. Among inspection, this turned out to be a superb site for ferns. Cheilanthes covillei was literally everywhere, along with several other species of ferns. Two dwarf cheilanthes similar to the one that I found earlier were here along with the grey foliaged C. lindheimeri. Many other ferns including pellaeas were prevalent among the huge patches of ball-type cacti. I've seen lots of ball cacti in the wild, but never any clumps as large as these. The other quirky find at the site were agaves growing in the wet creek bed. Usually agaves are found high and dry in well-drained spots, but these were currently growing in very soggy soils. I am certain that the creek beds dry out during the summer, but to find Agave chrysantha in this type of site is quite unusual.
Again, dark has begun to fall, so it was time for the 1.5 hr return drive back to Phoenix. Unfortunately, it was also time for every cow in the area to take a leisurely stroll down the same narrow winding mountain road. Unlike my small rental car, they were larger, had bigger horns, and were more numerous. I wish Chick-fil-a was more popular in these mountains.
For my final day in the field, I headed east of Phoenix toward the Pinal County town of Superior. I had admired the rock cliffs a year earlier when visiting Boyce Thompson Arboretum. Finding a highway pull off, I made my way down a steep cliff, then began the hike over and around boulder that made my car look like a miniature object. Although the elevation was only 3300', ferns were very prevalent as were agaves and penstemon, and Dasylirion wheeleri.
From here, it was east to the town of Globe, then south toward the town of Hayden. Just before Hayden, I ventured off the highway on a dirt road into the Dripping Springs Mountain. Staying out of the way of the three-wheelers, I admired the variation in the opuntias and cylindropuntias. There were several clones of wavy leaf padded opuntias, but the treasure here was a solid purple Cylindropuntia...probably C. imbricata. Cylindropuntia bigelovii was very prevalent, but I didn't find any unusual variants. Nice-size ferocactus were also quite nice, but not overly plentiful. The other highlight of this site was some huge agaves, that I assumed to be A. palmeri. These massive plants reached 7' wide x 4' tall... simply stunning.
From here, I headed back to the north to investigate the area around Roosevelt Lake, just east of Phoenix. This was another site for my quest fern, Adiantum capillus-veneris. I got within 3 miles of the site before the dirt road became unpassable for my 2-wheel drive vehicle. Since daylight was waning, it was time to turn around and head back to Phoenix, only to return another day.