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  • December 26, 2016 1:03 PM | Anonymous


    by Corri White

    Winter time visitors to zoos will often find themselves inside interior exhibits—it’s a great place to pretend to be off on a warmer continent somewhere. Helping to complete this illusion can be an array of tropical plant species, lovingly tended by zoo horticulturists.  And while it’s great to see animals surrounded by a realistic setting, many of the plants put on quite a show in their own right!

    One such plant is the purple- or white bat plant, Tacca integrifolia. Related to true yams (nb: not the sweet potatoes that get called yams in the grocery store, but that’s a topic for a different blog post), it grows wild across East Asia, from Pakistan to Borneo. Tacca is a forest understory plant that is inconspicuous except when in flower, when it produces a floral display consisting of several whitish bracts (leaf-like structures), long whisker-like appendages (called bracteoles), and dusky grey-purple flowers.  When viewed from a short distance, you might get the impression of a bat, hence the common name.  You can typically see Tacca flowering in January and February.  Don’t worry about smelling the flowers, though; descriptions range from “scentless” to “sort of stinky.”

     Denver Zoo - Tropical Discovery  

    Scientists believe Tacca’s complex flower structure and bad smell evolved to attract flies as a pollinator.  Although we often don’t think of it, flies are common pollinators.  A fly doesn’t get a reward for its services (Tacca produces no nectar, and flies don’t eat pollen), it is essentially tricked into doing the plant’s bidding.  If you find a plant with dark-colored flowers and an unpleasant odor, chances are that it’s trying to attract flies to pollinate it.  If your guests are needing a bit of a warm up during their Zoo visit, take some time to guide them into your zoo's horticulture winter display—and be sure not to miss the bat plant!

  • December 25, 2016 12:39 PM | Anonymous

    by azhadminKM


    Catalpa Sphinx Moth adult

    Catalpa sphinx moth (Ceratomia catalpa)

    Range: The catalpa sphinx is found throughout the eastern United States from Florida to New York, west to Michigan, and south to Texas and Colorado.

    Life History: This hornworm moth is about three inches long and gray brown in color. They are night flyers and do not feed as adults. They lay small, oval white-to-green eggs in mound-like masses of 100 to 1000 eggs on the underside of catalpa leaves. The eggs hatch in mid-May. The newly hatched caterpillars quickly begin feeding and can defoliate a tree in a short time. There are two types of caterpillars: one is dark in color with yellow sides and the other is light in color with orange sides. After three weeks, the mature caterpillar enters the soil and pupates. New adults emerge in two weeks and often a second generation of caterpillars is produced. At the end of summer the pupae overwinter in the soil to emerge in the spring. Total life cycle is about six weeks. Catalpa sphinx infestations tend to occur in cycles that are heavy for two to three years then almost nonexistent for several years. This may be due to the cycling of natural predators.

    Catalpa Sphinx larval stage, sometimes called "Catawba worm" or "fish worm" by fishermen.

    Damage: The Catalpa sphinx caterpillar feeds only on the northern catalpa (Catalpa speciosa) and southern catalpa (Catalpa bignoides) species. They can defoliate a tree in a short time if infestations are heavy, which can compromise the health of the tree, especially if defoliation is repeated during the growing season several years in a row.

    Management Tips:

    • The catalpa sphinx is preyed upon by parasitic wasps, which lay their eggs through the tough skin of the caterpillar. The wasp larvae eat the caterpillar from the inside out, and then spin a visible silken cocoon on the caterpillar skin.
    • Catalpa sphinx populations are controlled by many other predators, including birds, mammals, and fish.
    • Bt can be used to control the caterpillar. Read the label and watch for negative impacts on bees.
    Light form of Catalpa Sphinx larval stage.

    Sidebar: Fishermen prize these worms as fish bait due to their tough skin and juicy bodies. Catalpa caterpillars, called Catawba worms by fishermen, can even be frozen for fish bait and used at a later time. The Catawba worm is considered excellent bait for catfish.

    More Information:



  • December 24, 2016 12:28 PM | Anonymous

     by azhadminKM


    Public Garden Magazine, Summer/Fall 2012

    Climate change is threatening the world’s plant diversity at an unprecedented rate, yet plants are all too often left out of climate change discussion, policy, and action. Many have argued that this is largely a result of “plant blindness,” the inability to see or notice plants in one's own environment, and an inability to recognize the importance of plants in the biosphere and in human affairs... [Read More...]

    From Public Garden, Summer/Fall, 2012

  • December 24, 2016 12:23 PM | Anonymous

     by azhadminKM

    Two years ago, we decided to prune eight of our crape myrtles back to small tree status. They had not been taken care of for a decade and had grown 30 to 40 feet tall and were very gangly after so many years of neglect. After pruning, they flowered beautifully, but, about three weeks into flowering, we noticed what looked like white powder on the flowers and leaves. Unfortunately, zoo summer camp had started and it was another three weeks before I could inspect them to confirm that they had powdery mildew.

    Once powdery mildew was confirmed, the next thing that was needed was to determine what we could use to treat the trees, since they are used for browse. Consulting the list of pesticides approved by our veterinarian, horticultural oil and Neem oil were our best options. I started with Neem oil, using the seven-day application schedule recommended on the package (once every seven days). Over the next four weeks, we were able to reduce the impact of the powdery mildew. Even though we continued with a 14-day application schedule, we were never able to completely eradicate powdery mildew that season. The powdery mildew has come back for the last two blooming seasons, but we have been able to knock it back to an acceptable level, with just a little white on the trees, by treating with Neem oil every seven days.

    These crape myrtles appear to be Lagerstroemia indica, which are susceptible to this fungal disease. So that the pathogen is not spread to other plants, we clean the pruners after each use with a thymol solution, which kills most pathogens, including powdery mildew. Listerine “Original,” which has thymol as its active ingredient, is what I used; an inexpensive option.

    submitted by Larry Hintz, Gardener, Sacramento Zoo


  • December 09, 2016 12:52 PM | Anonymous


    by azhadminKM

    azh-2017-postcard-draftThe AZH Program Committee is now accepting proposals for presentations for the 2017 AZH Annual Conference Program in beautiful Naples, Florida. The Call for Presentations has all the information that you will need to submit a proposal for all presentations including directions, guidance, and deadlines. We rely heavily on professional zoo horticulturists for program presentations. Please consider sharing your experience and knowledge with your colleagues in AZH by being part of the AZH Conference program. If you have any questions or if you need motivation, please contact me at daileyc@jacksonvillezoo.org. We have experienced AZH Program Committee members ready to assist and guide you.

    Chris Dailey, AZH Program Committee Chair

  • June 15, 2016 12:59 PM | Anonymous


    by AZH

    Zoo arborists and municipal arborists share in common the need for high-level communication skills, the pursuit of excellent tree care amid a myriad of environmental stresses, and the ability to perform work safely in sensitive areas. The contributors to this Roundtable are professional members of the Association of Zoological Horticulture (AZH) (www.azh.org).    Full Article

  • June 14, 2016 12:05 PM | Anonymous


    An Inside Look at Zoo Arboriculture
    By: Michelle Sutton

    Whether they’re in-house or contracted, arborists who work in zoos have to be high-level communicators, coordinating work hour by hour with zookeepers. The tree work has to be done safely and without stressing the animals — yet efficiently, so that the animals are not removed from public view any longer than necessary.  



  • June 30, 2015 10:09 AM | Anonymous


    cartoon-certificateEver since its inception in 1980, the Association of Zoological Horticulture (AZH) has been dedicated to the advancement of zoo horticulture in zoological parks and aquariums. This dedication can be seen in AZH’s creation of its Zoo Horticulturist Certification Program. The program produced its first class of graduates in 2011. The program is offering its membership training that emphasizes the best practices in horticulture from the specific perspective of how these are utilized in the zoo and aquarium environments. Among the program’s goals are to provide an integrated and comprehensive training program on the unique aspects of zoo and aquarium horticulture that will ensure the highest level of excellence, technical expertise and professionalism among AZH members. These professional development courses also promote the exchange of ideas and networking opportunities among zoo horticulture colleagues.

    Certification consists of four two-credit core courses and two elective courses at one credit each. Horticulturists who participate in a course and who successfully pass the in-class examinations will earn credits towards the 10 credits required for certification. The core courses, as determined by the AZH Board, are: Integrated Pest Management, Soils, Exhibit Design I, and Browse and Toxic Plants. Elective courses will include Water Management, Plant Conservation/Education, Record-keeping, and Design II. Initially, the training was part of the schedule of the AZH Annual Conference. The first full-day training course on Integrated Pest Management (IPM) was offered in conjunction with the 2007 AZH Annual Conference in Tulsa.

    Instructor Carol Glenister, IPM Labs, Inc., works with Rick Knight (Topeka Zoological Park) to identify insect pests with a hand lens at the inaugural course in Tulsa in 2007. Photo by Terry O’ConnorInstructor Carol Glenister, IPM Labs, Inc., works with Rick Knight (Topeka Zoological Park) to identify insect pests with a hand lens at the inaugural course in Tulsa in 2007. Photo by Terry O’Connor

    Creating the courses and administering them has been a full out endeavor and one of the primary areas of work for AZH. The development of each course begins with the assignment of a course administrator who works closely with the outside consultant AZH has hired to facilitate course development and management. This team first defines the course goals and outcomes, and determines pertinent topics that need to be covered in the course. Instructors with relevant expertise are then selected from within the AZH membership and from universities, businesses, agencies and other organizations.

    Online courses are currently being developed through San Diego Global Academy. The first online course, "Browse and Toxic Plants," is now available (click on the "eLearning Site" below).
    eLearning Site

    AZH’s mission is to promote excellence in zoo horticulture. The Zoo Horticulturist Certification Program supports this mission by providing its graduates with the tools they need to apply new skills and practice quality horticulture in a zoo or aquarium environment. Certification will advance the profession of horticulture within the zoo and aquarium industry and enhance the ability of horticulturists to contribute to the success of their organization’s mission..

  • June 30, 2015 9:34 AM | Anonymous

    What comes to mind when you think about zoos? Well animals, of course! But just imagine a zoo without plants... Animal exhibits lacking the natural effect that plants provide. Few places for animals to interact, and visitor areas without plant displays and shady spaces to retreat to. What is "zoo horticulture"? A simple description might be "gardening and landscaping activities which occur in a zoo or aquarium setting." But there is so much more!

    Zoo horticulture encompasses activities that range from exhibit/landscape design, development, and installation, to managing plant material within exhibits and visitor areas; from providing plant material for animal "diets" and "enrichment" (things that "enrich" the lives of zoo animals), to assisting zookeepers in identifying potentially toxic plants; from establishing interesting plant collections to promoting the awareness of plants and plant conservation. Zoo horticulture is so much more than just gardening and landscaping!

    Animal exhibit and landscape development:

    Most modern zoo exhibits incorporate the idea of placing animal species within the context of a "natural" environment as much as is possible. Plant materials, both living and non-living (such as logs, roots, and limbs), are vital to creating this natural environment. The zoo horticulturist is an important part of the planning and design process, and installation of new zoo exhibits. The zoo horticulturist interacts with architects, animal curators, administrative staff, construction companies, landscape contractors, nurserymen, and others in all stages of exhibit development. As an adviser to the project, the zoo horticulturist recommends suitable plant materials and offers strategies to ensure critical plant requirements are met for the successful growth and development of plants used in the project.

    Managing landscapes within exhibits and visitor areas:

    The zoo environment is a "rigorous" environment for plants to say the least! The zoo horticulturist is challenged with the task of keeping exhibits looking natural and "fresh"—not an easy task when one considers the "abuse" which plants incur. Whether it's soil compaction from hoof stock such as zebras, giraffes, etc. or defoliation from herbivores, plants are damaged or have difficult growing conditions to contend with, and it's the zoo horticulturist's job to meet the challenge!

    Development of browse and plants for animal enrichment:

    The zoo horticulturist is called on to assist curators, zookeepers, and commissary managers in identifying, locating, and nurturing plant materials for a zoo's animal collection. The zoo horticulturist's knowledge is invaluable in providing "browse" plants for specialized animal diets and supplementing regular diets. Many zoos maintain blocks of plants ("browse") specially suited and available for the dietary needs of the zoo's animal collection. Of special concern is the identification of potentially toxic plants and ensuring that zoo animals do not have access to them.

    Establishing interesting plant collections:

    At the heart of the horticulturist or gardener is a desire to share the world of plants with others, and what better way than to establish and maintain collections of plants to capture the interest of zoo visitors. Zoos are often recognized for their beautiful, engaging collections of plants. Plant collections allow visitors to learn fascinating facts about plants and their importance to all life on earth.

    OLYMPUS DIGITAL CAMERAConservation of plants and the environment:

    Zoo horticulturists are actively involved in conservation efforts and reminding the public that many plant species are also threatened from habitat destruction and other forces. Zoo horticulturists are often the key people in their institution's efforts to "reduce, reuse, and recycle." Composting of zoo wastes is often the job of the horticulture/grounds maintenance department.

  • January 30, 2015 11:26 AM | Anonymous member (Administrator)

    The first time I noticed considerable foliar damage on our tulip poplars was last June. The reason I noticed it may be due to the fact that I planted some young trees two years ago and they are still relatively small, about six to eight feet tall. Most of the foliage is at eye level so it was easier to spot. I observed brown spots and yellowing, and upon closer inspection, saw many black beetles on the leaves. I couldn’t identify them immediately but they had elongated appendages near their noses that looked like snouts—a feature that distinguishes weevils. After an internet brief search, I identified them as yellow poplar weevil, Odontopus calceatus. Once aware of them, I started scrutinizing all our tulip poplars and found that even the tall ones (30 feet and taller) showed similar damage.
    Generally, this pest is found east of the Mississippi River, where its native, preferred hosts, tulip trees (yellow poplar) and sassafras occur. The adults create bean-shaped pits where they feed on the leaves—especially those of tulip trees, sassafras, southern magnolias, and sweetbay magnolias. The larvae also cause blotchy leaf mines. The adults are more conspicuous, as a summer generation emerges suddenly in late June. They look like large ticks and people often mention the “flying ticks” they find on their clothes.

    As with most leafminers, this pest is easier to manage if the adults are targeted. Every few years, an overabundance of adults emerge in June and July. This turns out to be more of a nuisance than seriously damaging to plants. Various control methods for this beetle include biological control, which involves natural parasites and predators that attack the larvae and pupae within the leaf mines. Cultural control can be achieved by eliminating preferred host species, such as sassafras trees and sweetbay magnolias. Chemical control involves applying a contact or stomach insecticide to kill the adults as soon as they begin feeding on the leaves. Several systemic insecticides are registered for control of leaf-mining insects and are effective in controlling the larvae. The best time for application is when the eggs have just been laid or while the mines are still greenish in color. Once the pupae are present in the mines, it is too late for the insecticides.

    This must have been one of those bumper crop years for the weevils as there were numerous adults on most leaves. Much of the damage by the larvae had already occurred so I set out to deal with the adults. Since the trees were planted close to the gorilla yard, I could not spray any conventional insecticides. I decided to dislodge the adults with daily blasts of water from the hose. I also set up an impulse sprinkler to help knock them off and discourage repopulation. After a few weeks they disappeared, but I understand that the adults would normally persist for only a few weeks. Next year I will be vigilant and check for the adult weevils, which overwinter in leaf litter until spring temperatures cause trees to produce new leaves, usually in April and May. The adults feed for a period of time and eventually, mated females hollow out a small pit in the lower mid-vein of a leaf and deposit one to 15 eggs. And the cycle begins again. Most of the information in this article and more details about this insect can be found at:  https://bugguide.net/node/view/51464

    Submitted by Susan Pierce, Pittsburgh Zoo

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