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  • June 10, 2018 6:47 AM | Anonymous


    Some of you may have heard me talk about how as zoo horticulturists we respond to many problems others in our field typically would not. For example, when a Komodo dragon decides to eat the four-foot Agave americana that has been in the exhibit for over a year or when the hot grass goes down in an elephant yard and the resident pachyderms destroy an entire tree. You can try to scold the animal, yet I have found dragons to be quite unrepentant. I often say to friends when describing my day that I had “tapir problems” or “crocodile problems.”

    Speaking from experience, I would say that bird problems are the worst. The plants are coated in bird feces, the soil is either drenched or too dry, and mechanical damage is a given. New plants are either picked apart by the birds or crushed by keeper hoses. Pruning is a harrowing experience as birds spontaneously freak out and fly into the wall. Light conditions are abysmal.

    I have been responsible for the Bird World exhibits at the Denver Zoo for four and a half years and have found the small triumphs of growing plants in the exhibit to be both extremely satisfying and frustrating. What makes working around birds so amazing is when you win. When you find that right plant for the right place. The plant that was defeated in one area can thrive when placed in a different location. I have killed a lot of plants in Bird World—a lot. It took years of trials to figure out a workable palette to represent each ecosystem held in the building. Five habitats are presented:

    • Rainforest: a large room with several full-sized trees, multiple pools, and a waterfall. Anona squamosal, Dieffenbachia, Dracaena, Codiaeum variegatum, tree ferns, cycads. Very dark and in need of continuous pruning.
    • The Jungle: smaller with one large Ficus, Alpinia, and Trichelia dregeana (Natal mahogany). Too wet and too dry.
    • Tropics: black olive, Citrus mitus, Crinum lilies, Anthurium hookeri, Codiaeum variegatum. Was over-watered and trampled by previous keeper—now doing quite well!
    • Aquatics: Ficus nitidia (dying from white fly), Alocasia portora and ordata, Agalonema ‘Shamrock,’ Dracaena reflexa ‘Song of India,’ Codiaeum variegatum, Trichelia dregeana. Constantly saturated.
    • Swamp: Ficus benjamina, Dracaena, Spathiphyllum, Zamia furfuracea, Spanish moss, assorted tillandsia. Ironically, the driest room of the building.


    I have learned to manipulate classic mall plants such as Agalonema, Dieffenbachia, and Spathiphyllums to look somewhat natural. My favorite Agalonema to use in many of the exhibits is the cultivar ‘Shamrock.’ The leaves are solid dark green, not the typical plastic looking gray stripped. They work great as a filler and I have several that have thrived for years in the Aquatics room even though it is regularly blasted with a hose and in sitting water. There are also quite a few Dieffenbachias that do quite well and blend with the natural look ‘Camouflage’ and ‘Jungle Boogie’ are decent cultivars. Codiaeum and Cordylines are great for pops of color and do well if they can receive enough light.

    The Ficus trees in the Aquatics room developed a white fly problem a few years ago that has yet to be fully controlled. We have used every tool in the IPM arsenal that has been approved by veterinary staff. The beneficial insect Encarsia formosa was released on multiple occasions with varied results. The material the eggs come on is difficult to keep in place and is also an eyesore. The paper tags would get wet and fall from the trees before the eggs could hatch. Delphastus pusillus has also been released in several exhibits, more successfully in the smaller rooms with less significant infestations. Averaging $500 per release, it is cost prohibitive to have a beneficial program that will truly control the problem in such a large building. Insecticidal soap was not approved as we have two Sloths and sensitive birds in the room. In a desperate attempt to save the trees, a low concentration Imidacloprid soil drench was applied and helped for a short time. We would like to avoid reapplication. Currently, we are consulting with Arborjet to find a formula that will be presented to vet staff for future use. A baby sloth was born a few months ago, so we may have to wait for some time. Sloth problems.

    Three years ago I decided to give giant Alocasia a try. The first species planted was portora which has happily grown into an eight foot tall monster. We have also had great success with odora and macrorizos. After years of thriving untouched in the Aquatics room, one or both of the sloths decided to use the portora as a Slip-n-Slide, shredding the leaves with telltale two-toed gashes. Sloth problems.

    Many of the original trees planted with the building’s inception are still doing well and have withstood continuous hard pruning and harsh growing conditions. Bucida buceras (black olive) tree continues to thrive in the Tropics room. It has shown resistance to white fly and other pests and has a lovely growth habit. Our arborist treats it yearly with Cambistat to slow growth and reduce the need for heavy pruning. I definitely recommend adding this tree to an existing exhibit or new design. Annona squamosa (a relative of cherimoya known as alligator apple) is doing well in the Rainforest exhibit and has even produced fruit. Natal mahogany, (Trichelia dregeana) works well as a filler in tight spots and can be cut back regularly. Although Ficus are famous for being the toughest of them all, I will not recommend them due to their susceptibility to white fly, especially in a closed environment.

    We recently moved in two Cycas circinalis that were outside all summer and had received some cold damage in the fall. After losing the majority of their foliage, they were close to being removed when new shoots began to emerge from the crown and within weeks had grown several feet. They are doing well at this time.

    While visiting the Houston Zoo with AZH in 2014 Corri White and I were impressed by the gravel mulch used in many of their bird exhibits. Upon our return to Denver, we introduced the idea to our bird staff. It was not met with much enthusiasm. After multiple negotiations they agreed to let us try it in the smaller Swamp exhibit. Then came the task of selecting the proper substrate. We presented them with multiple options from local purveyors as well as shipped in samples from around the country including what they use at the Houston Zoo. Every one of them was rejected for being too sharp, too round, too big, too small. Nearly a year had passed by with no progress when on a totally unrelated trip to a local hardscaping facility, I happened to see a bin of small-but-not-too-small gravel. I asked the rep what it was and he said it was just regular old squeegee! I took a sample back to the zoo and it was instantly approved. It had been hiding in plain sight the whole time. The installation was a success and we were asked to use it in the Tropics and Aquatics rooms. All was well until our female sloth decided to start eating it. We had to remove three tons of gravel by hand immediately. Sloth problems.

    I will be handing over the building to a new horticulturist soon and although I will not say I will miss it, I had some interesting adventures and learned to never give up finding the right plant for the right place.

  • June 07, 2018 6:51 AM | Anonymous


    Happy spring, fellow AZH members!

    It is with much excitement that I write this letter and update for the first time as your President. I am truly honored to serve the membership and have been working with the board of directors on some very important initiatives for our organization—all based on feedback from you. Your voice matters and is the driving force for this organization!

    Most of the board members were able to travel to Winnipeg, Manitoba back in February for the mid-year board meeting. These meeting are long but exciting and it is so much fun to be able to bring all of our passions together in order to strategize the upcoming imperatives for the organization. This year’s conference in Winnipeg is shaping up to be a truly robust program and memorable visit for us all. I can’t wait to see everyone in August! I registered—did you?

    As the year shapes up for us all, a large focus is being placed on committees. Committees are the “bread and butter” of AZH and the most fun and effective way to get involved, be heard, affect change, and form meaningful professional ties among fellow members. We are working with committee chairs to update each committee’s mission statement and member roster. Each committee will also be assigned a board representative in order to facilitate communications.

    Our website continues to be a focus as well. It is, after all, our primary representation and resource tool. The communications committee is working hard to keep the site up to date with information and get your expertise and knowledge in there. That info does not come out of thin air! We need YOU to do that. So start blogging, keep perusing the site, jump in on discussions, and PLEASE let us know what you want to see and read!

    Lastly, a call for nominations was sent out to the membership at the beginning of April. Please give careful thought and consideration to your nominations and whether you think that your service as a board member is a good opportunity for you. Serving on the AZH board over the past three years has been an incredibly honorable and fun experience for me.

    Corri Pfeiffenberger, AZH President

  • June 07, 2018 6:49 AM | Anonymous


    Two years ago we said goodbye to a truly inspiring and great contributor to horticulture, zoo horticulture, and conservation. Wendy Andrew was a longtime AZH member, board member, served as president for two years, and hosted two AZH annual conferences at Disney’s Animal Kingdom. Wendy was passionate about horticulture and helping others as evidenced by her missionary work overseas and service on the board of ECHO Global Farm, a global Christian organization that equips people with agricultural resources and skills to reduce hunger and improve the lives of the poor. Her contribution to our organization was immense and AZH is a better organization because of her dedication.

    Wendy’s work and memory are the foundation of the Wendy Andrew Cultivation Grant The WACG has funded five projects for a total of $5,600 in the two years since its introduction to AZH. This year I am pleased to announce the following grant recipients:

    Butterfly Pavilion—Browse Café

    Rolling Hills Zoo—Bringing Bees Back to the Garden

    Sacramento Zoo—Plant Identification/Signage

    Zoo New England—Organic Garden

    Congratulations to the winners!

    These projects are perfectly aligned with the goal of the grant to support work that promotes zoo horticulture. Well done!

    The AZH Wendy Andrew Cultivation Grant seeks to support member projects that promote zoo horticulture and are outside the scope of the existing plant conservation grant program.

  • June 05, 2018 6:53 AM | Anonymous

    The program committee has released the 2018 program schedule for our 2018 AZH conference in Winnipeg!

    You can find the schedule on the Conference page of the website.

    Thank you Chris Dailey and the Program Committee for all of your hard work pulling this together.  Looks to be an amazing year!

  • March 17, 2018 6:54 AM | Anonymous

    Horticultural activities at Jacksonville Zoo and Gardens was recognized in a recent article "Exotic Landscapes" (March 10, 2017, Florida Nursery Growers andLandscapers Association). Chris DaileyAZH member and the zoo’s horticulture manager, explains the role that horticulturists play in zoos today.


  • February 25, 2018 6:58 AM | Anonymous

     By Joell Dunham, Sedgwick County Zoo

    Several facilities have hosted traveling exhibits in order to boost attendance or to increase revenue. Last year, a survey was conducted by the Information and Survey Committee to help answer some of the questions about hosting a traveling exhibit. Here are the results: 20 AZH members representing 18 facilities responded. More than 55 percent said they have hosted a traveling exhibit; 25 percent said they had in the past, but not recently; and 15 percent said they had not hosted a traveling exhibit before.

    Of those that hosted traveling exhibits before, 75 percent said that the traveling exhibit stayed 3–6 months. Most of the facilities sought out the exhibit that they wanted to host. Traveling exhibits that AZH facilities have hosted include: The Scoop on Poop; Penguin Landing; Komodo Dragon; Biomechanics: The Machine Inside; The World of Giant Insects; Crittercam; Lorikeets, Budgies & Cockatiels; Koalas; Reptiles: The Beautiful & the Deadly; Minotaur Mazes; Tarantulas & Bugs; Lego; Geico Gecko; Big Bugs; Washed Ashore; Extreme Bugs; Wooly Mammoth; Sustainable Seafood; Clyde Peeling’s Frogs: a Chorus of Color; and Dinosaurs.

    Each exhibit required some preparation. In some cases additional electrical outlets or lights were needed. In others extra water and air lines had to be installed. Larger equipment had to be rented, platforms had to be built, and protected storage had to be set up for empty crates during the run of the exhibit. Each traveling exhibit differed with regard to who was responsible for the care of animals (if present), repair of equipment, and who was trained to maintain the exhibit.

    The companies that proved easiest to work with demonstrated certain characteristics: it was easy to reach the company or the person in charge, questions were answered quickly, instructions were clear and concise, timelines were followed, and the public enjoyed the display. Almost all of the respondents said that talking with a facility that had hosted the same traveling exhibit before was very helpful. Close to 80 percent of the facilities that have hosted traveling exhibits in the past said that the goals for hosting the traveling exhibit were reached.

  • February 18, 2018 7:09 AM | Anonymous


    By Amy Yarger, Butterfly Pavilion

     If you’re reading this blog, you’re probably familiar with the tenets of integrated pest management (IPM) in your plant collections and landscape. Due to some recent alarming die-offs of both native and managed bees, as well as widespread declines in pollinator populations, agriculture scientists are promoting the benefits of an IPPM approach. The extra “p” is for pollinators, those small (and I think adorable) animals that play the role of Cupid in plant reproduction. Because of the zoo world’s emphasis on conservation and our role as highly visible models for sustainable landscaping, this model may be a good fit for zoo horticulture as well.

    First of all, IPPM merely adds another lens through which to conduct regular pest management in the outdoor landscape; it does not require all new tools and processes. IPPM monitoring protocols track and document pests, but also investigate what pollinators are in the area and what plants they use for forage and shelter throughout the year. When pest management tactics are implemented, the tracking of pollinator populations before and after provides insights about potential harmful effects.

    Thresholds may also shift under IPPM, especially in areas designated as “butterfly gardens”. After all, caterpillar is only another word for baby butterfly. If you can’t abide chewing on milkweed, a monarch habitat is probably not the garden for you! On the flip side, managing infestations while they are small and not established, may allow one to avoid extreme pest management measures. Plants that are “problem children” are disinvited from the garden party.

    Many physical, cultural and biological methods are compatible with sustaining healthy pollinator populations. Not all, however – have you ever seen a praying mantis devour a butterfly? I have! It is important to note also that chemical pesticide use is not necessarily forbidden – a thorough examination of what, when and how a chemical is used is key. Also, the IPPM approach places emphasis on timing and prevention of contamination of the surrounding habitat. Chemicals that have not demonstrated negative effects on pollinators still must be used with every precaution to prevent collateral damage. Once you see a bee die-off, you never want to see one again!

    In outdoor landscapes, IPPM focuses not only on plant health, but on biodiversity and ecosystem services, creating opportunities for pollinators as well as other beneficial insects and even vertebrates such as songbirds. Ecosystem gardens cultivate a livelier aesthetic that encourages exploration and discovery and allows connectivity for urban wildlife. If your zoo has expressed an interest in pollinator conservation or education, IPPM might be worth looking into!

  • February 18, 2018 7:02 AM | Anonymous

     Email from Stephen Butler, Curator of Horticulture, Dublin Zoo Phoenix Park, Dublin

    Hello everyone, hope you are all well and looking forward to seeing Dublin Zoo this year, the weather will be wonderful, the company excellent, and the venue perfect!

    Please find attached 3 files:

    1. Registration Form, with costing. Please read carefully and return as early as possible, and before April 23rd.
    2. Field Trip notes, on the gardens and nature reserve we are visiting.
    3. Preliminary programme describing the speakers we have already booked, but please note we will have room for many of you to talk about any successful planting you would like to share, for any reason, animal, educational, decorative, or simply very useful
    Please note, city centre hotels were far too expensive, we are instead a little outside Dublin, and will arrange transport to save everyone staying at the Springfield Hotel time and money getting to the zoo. The coach will also pass the second hotel listed and we should be able to collect from there too. Please do tell us if you are staying at either hotel!

    Please note, for anyone travelling home on Friday 11th, our last field trip is only 13kms from the airport, easy to get there for evening flights.

    For enquiries about the conference please email Aoife at Aoife.Keegan@dublinzoo.ie

    Stephen Butler Dip.Hort.Kew
    Curator of Horticulture
    Dublin Zoo
    Phoenix Park, Dublin 8

    E sbutler@dublinzoo.ie

    W www.dublinzoo.ie


    Dates for the Diary

    Event (Click for Details)


    27 January 2018 Hedge Laying RHS Garden Rosemoor, Devon
    2 February 2018 Winter Tree ID Cambridge University Botanic Garden
    3 February 2018 Winter Tree Identification RBG Edinburgh
    10 February 2018 Lichen Identification RBG Edinburgh
    21 February 2018 Mosses, Lichens and Liverworts RHS Garden Wisley, Surrey
    2 March 2018 Introduction to Tropical Ecology Cambridge University Botanic Garden
    16 March 2018 PlantNetwork: What you need to know about Access and Benefit Sharing and the Nagoya Protocol Chester Zoo
    18 – 19 April 2018 PlantNetwork Annual Conference RBG Kew, London
    9 – 11 May 2018 EAZA Zoo Horticulture/BIAZA Plant Working Group joint conference Dublin Zoo, Ireland
    10 May 2018 Introduction to Bee Identification & Diversity Cambridge University Botanic Garden
    12 – 13 May 2018 The Arb Show Westonbirt Arboretum, Gloucestershire
    17 May 2018 PlantNetwork: Plant Records training day Cambridge University Botanic Garden
    20 May 2018 Wildflower Identification RBG Edinburgh
    22 – 26 May 2018 RHS Chelsea Flower Show Royal Hospital, Chelsea, London
    6 – 8 June 2018 BIAZA Annual Conference & AGM 2018 Shaldon Wildlife Park/ Living Coasts, Devon
    12 June 2018 Tree Identification In Summer RHS Garden Wisley, Surrey
    3 – 8 July 2018 RHS Hampton Court Palace Flower Show Hampton Court Palace, East Molesey, Surrey
    26 June 2018 PlantNetwork: The restoration and integration of natural habitats in a designed landscape Wakehurst Place, West Sussex
    28 – 29 June 2018 Ancient Tree Forum Summer Conference Courtyard Theatre, Hereford
    18 – 22 July 2018 RHS Flower Show Tatton Park Tatton Park, near Knutsford, Cheshire
    3 August 2018 Scything for Beginners RHS Garden Rosemoor, Devon
    6 September 2018 Seeds - Collecting, Saving and Sowing RHS Garden Hyde Hall, Essex
    18 – 22 September 2018 EAZA Annual Conference Athens, Greece
    2 October 2018 Introduction to the Science of Algae Cambridge University Botanic Garden
    21 – 22 November 2018 Identifying conifers Cambridge University Botanic Garden
  • February 06, 2018 7:16 AM | Anonymous


    2017 Conference: Ghosts and Gators

    By Andrew Lyell, Senior Gardener, Los Angeles Zoo

    I’ve seen a ghost! No, not a spectral image from spooky tales, but a ghost orchid. This beautiful and unusual plant occurs naturally in swampy areas of Florida, which is where this year’s Association of Zoological Horticulture (AZH) conference took place.

    The beautiful and unusual ghost orchid occurs naturally in swampy areas of Florida. Though it wasn’t in bloom for the conference, I did see pale ghost orchid roots gripping a tree trunk at the Naples Botanical Garden. Photo by Andrew Lyell

    It wasn’t in bloom at the time, but I did find its pale roots gripping a tree trunk at the Naples Botanical Garden, one of several wonderful sites we visited during the weeklong conference.

    This year’s host was the Naples Zoo at Caribbean Gardens. The conference was originally scheduled for September, but due to storm damage from Hurricane Irma, it was postponed until December. By then, the roads were cleared, water drained, and all was safe for the attendees.

    The conference program featured many presentations about successes and failures, both in zoos and natural areas. Topics ranged from disaster preparedness to how different types of equipment meet the diverse needs of parks. My Los Angeles Zoo colleague Sandy Masuo gave a very well received presentation about using succulents as ambassadors to engage guests with plants and help lead people to a better understanding of the role plants play in our lives and the health of our planet.

    One presentation that caught my attention was by Houston Snead of Jacksonville Zoo and Gardens, who talked about getting involved with plant conservation at a grass roots level. He explained how he made connections with people who helped him along on his journey to protect declining populations of fringe orchids (Platanthera chapmanii) in Florida. Many individuals and organizations provided support, and he was ultimately able to secure protected status for this plant from the state of Florida. AZH also provides many types of support for plant conservation programs around the world including grant funding. Success stories like Houston’s inspire me to increase my own efforts at plant conservation. As Frank Pizzi, curator of horticulture at Pittsburgh Zoo, put it, “Sharpen your pruners and get going!” 

    One large ficus tree at Naples Zoo sheltered numerous birds and supported a variety of epiphytic plants. Photo by Sandy Masuo

    Naples Zoo is home to many different animals, but I was there for the plants! Many tropicals accentuate the exhibits and provide a shady respite for visitors to escape from the Florida sun. It was under these trees that I enjoyed talking with fellow attendees and other zoo guests. We were particularly impressed with one large ficus tree that sheltered numerous birds and supported epiphytic plants, just like the ones I saw in the swamps. 

    Local people named many of the giant cypresses. “Asteenahoofa” was very impressive! Photo by Andrew Lyell

    Naples lies on the coast of the Gulf of Mexico and is surrounded by plenty of wetlands. We visited the Audubon Corkscrew Swamp, which is dominated by bald cypress trees. (These are featured around the tomistoma pools at the L.A. Zoo, though because they are growing on dry land, they do not form the characteristic “knees” that they develop in their natural habitat—an adaptation to help the trees breathe in watery conditions.) Some are so massive that they are virtually a habitat by themselves. Large strangler fig trees were enveloping some of the cypresses, Spanish moss draped languidly on the branches, and tillandsias (air plants) clung tenaciously with their aerial roots all over the trees. Various birds and reptiles and insects also took refuge in the trees as well as seeking food there. Many cypresses were named by the local people. One that left a big impression on me was a giant called “Asteenahoofa” by the Seminoles.

    Swamps are amazing ecosystems. They are able to absorb the power of hurricanes practically unscathed, and any damage done is quickly “up-cycled” into other life forms. I saw two massive cypress trees that were downed during the recent hurricanes, but, as nature intended, other life forms were quickly colonizing the logs. Animals were sunning themselves on them or hiding in them. These trees also become “nurse logs” for many other types of plants.

    Visiting the swamp, had visions of dodging alligators and running across their backs as in the ’80s video game, Pitfall. But the only gators I saw were sunning themselves near drainage canals—and at the Naples Zoo. Photo by Sandy Masuo

    Since I hadn’t visited a swamp before, I expected to see alligators—lots of them. I had visions of dodging them and running across their backs as in the ’80s video game, Pitfall. But it wasn’t until we left the area and were traveling down the highway that I spied some gators hauled out on the bank of a drainage canal sunning themselves. And the mosquitoes that I was also expecting must have been blown away in Irma, because I didn’t encounter any during my stay—not even in the swamps, which I thought were infested with the wee beasts. I saw more mangrove crabs in the mangrove swamp than mosquitoes.

    I encountered more mangrove crabs than mosquitoes. Photo by Sandy Masuo Naples Zoo staff performed miracles to make this meeting happen and the zoo looked amazing—kudos to former AZH President Danielle Green and her staff for hosting a great conference!


  • February 01, 2018 7:20 AM | Anonymous


    By Sandy Masuo, Los Angeles Zoo

    Characteristic holes in pine bark that was removed from a dead tree.

    In November, many Los Angeles Zoo staffers arrived at work to find tree crews removing dead pines from the hillside around Zoo Grill—casualties of the ongoing bark beetle epidemic in Southern California. In addition to some 200 native species of bark beetle, 20 invasive species have been documented in California. Prolonged drought stresses trees, which, like animals, have immune systems that normally defend against pathogens and parasites. In their weakened state, trees are more susceptible to disease and infestation. So although these tiny beetles (only about 1/8th inch long) are normal denizens of our California ecosystem, under the drought conditions of recent years, their populations have swelled, contributing (along with other factors) to mass die-offs of trees, which in turn contribute to catastrophic wildfire and erosion. Between 2012 and 2016, California lost some 100 million trees.

    Bark beetles leave telltale holes in the external bark where adult insects have bored through to the phloem, or inner bark, where they lay their eggs. Both adults and larvae feed on the nutrients that flow there and disrupt circulation. A healthy tree can withstand a limited infestation—but too many beetles can kill even a robust tree. The beetles emit an aggregating pheromone that acts as a beacon, drawing more beetles to the site. Many also carry fungi that can infect the tree, hastening its death. In some cases, symbiotic fungi are part of the beetles’ life cycle. According to the Los Angeles Times, a 2014 survey at the Huntington Library, Art Collections, and Botanical Gardens in San Marino (about ten miles from Los Angeles) found that 207 of 335 species had been attacked and more than half contained beetle-vectored fungi.

    Among the invasive bark beetle species, one of the most destructive is the polyphagous shot hole borer (Euwallacea fornicatus), aka PSHB. First discovered in California in 2003, the tiny insects are thought to have been accidentally imported from Asia in packing materials or wooden shipping pallets. These beetles are similar in appearance to the bark beetle and females carry the spores of a symbiotic fungus that they plant in the bark of host trees to provide a food source for their larvae. PSHB attacks more than 200 species including commercially valuable trees such as avocado and important natives such as California sycamore and coast live oak.

    The widespread nature of these infestations is such that we must rely on scientists to find a large-scale control. However, poor pruning practices, improperly cleaned garden tools, and the transportation of cut wood contribute to the spread of these insects.

    Learn more about bark beetles at http://tinyurl.com/y935swh9 and PSHBs at http://tinyurl.com/y8pnjtwv.

    New York Times, December 12, 2017, “Widespread Tree Die-Offs Feared” by Jim Robbins


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