by azhadminKM

Callery pear has become an invasive tree species.

By Rick Knight, Zoo Horticulturist
Topeka Zoo and Conservation Center

Pyrus calleryana, Callery pear, is native to China and Vietnam, and was introduced into the United States in the early 1900s by the Arnold Arboretum of Harvard University. It is an ornamental, deciduous, medium-sized tree with white flowers and good fall foliage. It has a small fruit that is eaten by birds, which disperse the seeds. The various cultivars are generally thought to be self-incompatible, unable to produce fertile seed when self-pollinated. But they are fertile when cross-pollinated with other cultivars. Callery pear seedlings are now taking over old fields along roadsides and wasteland and are a new weed species. They now are on many states’ list of invasive species and are headed west.

 

by azhadminKM

By Danielle Green, Director of Gardens & Grounds, Naples Zoo at Caribbean Gardens

Naples Zoo at Caribbean Gardens is a special place. Within these 45 acres in the heart of Naples are living reminders of the history of this property and its evolution from a personal garden of Dr. Henry Nehrling to the world class zoological garden that it is today. Caring for the historic specimen trees that we have on the property requires a plan that includes inspection and routine plant health care. As part of our plant health care, we perform annual deep root fertilization on more than 30 specimen trees around the Zoo. 

Deep root fertilization is a process where a specially formulated nutrient solution is injected into the root zone (area under the canopy) of trees. The nutrients are injected under pressure which helps aerate and provide oxygen to the root system. The soil injection begins just below the surface and goes to a depth of up to 12 inches beneath the soil. Injection sites are placed two feet apart in a grid pattern under the canopy area and beyond the drip line of the tree. Our tree-care partner, Davey Tree, uses a patented product (Arbor Green PRO) designed by the Davey Institute to mimic the natural availability of nutrients in the forest environment. This ensures that these gentle giants get the nutrients required for healthy growth and development. Just a few benefits of these nutrients include increased root growth, improved pest and disease resistance, greener foliage, and better drought resistance.

Many of our “gentle giants” at Naples Zoo are the largest of their species found in Naples. These include two Ficus altissima or lofty fig found on Bear Loop, the Pterocarpus macrocarpus or Burmese rosewood near the Caribbean Gardens buildings, Delonix regia or royal poinciana in Bear Loop playground, and at panther viewing area we have a Roystonea regia or royal palm that is nearly 100 years old! Other specimens to take notice of are the four Ceiba pentandra or kapok trees. Kapok trees are native to tropical America from Mexico to the Amazon basin and are also called silk-cotton trees. Kapok flowers open at night and are pollinated by bats; the pods that form later can produce up to 200 seeds embedded within a silky, cotton-like, water-resistant fiber. This fiber was once used as stuffing material for life jackets and mattresses. The massive trunks are covered in thorns and can grow up to 10 feet in diameter. The oldest known Ceiba sp. trees are found in Miami and are 200 years old! Be sure to check out our signature icons at the 2017 AZH annual conference zoo day at Naples Zoo in September!

by Robin McCain, Woodland Park Zoo

Nitrogen and iron are the only nutrients in which woody plants are commonly deficient. Fertilize only as needed and only if other problems for poor growth have been eliminated. Avoid over fertilization, especially with high-nitrogen, fast-release fertilizers. Over-fertilization promotes excessive foliage growth that may result in an increase of pest populations such as mites, aphids, and psyllids. It also may cause bark to crack, allowing entry of disease, may damage roots, and cause burning or die back of foliage.

 

by azhadminKM

A flurry of activity has been going on since the AZH annual conference and I wanted to update everyone on some exciting changes. First, the AZH Communications Committee in conjunction with the AZH board of directors has initiated a new format for our traditional newsletter. In an effort to maintain a fresh and professional standard of communication, we will publish articles in a blog format on the AZH website. This will replace the bimonthly publication that you are accustomed to receiving via e-mail. These articles can still be printed to share with staff but will require you to log in to the members area to view updates on projects, new exhibits, IPM, and conservation articles. This blog will be updated quarterly with content that has been submitted by individuals and committees. Our hope is that this new format will encourage AZH members to submit more content for publication. Anyone can submit a short blurb or article no matter the size or scope and be sure to include pictures! Use this online “Newsletter Submission Form” to submit an article.

Additionally, Hassena Kassim (Phoenix Zoo) has taken a position at North Carolina Art Museum and resigned her position on the board of directors. We have asked Donita Brannon to fulfill the remaining time of her term on the board as director-at-large and she has accepted this appointment. Thanks to Hassena for her service to AZH and congrats to Donita!

Lastly, the first recipients of the AZH Wendy Andrew Cultivation Grant were chosen at the recent mid-term board of directors meeting.

• Providing Interactive Plant Education & Conservation Connections
  Buffalo Zoo - Melanie Anderson: $1000

• Sacramento Zoo Specimen Tree Signage project
  Sacramento Zoo - Michaele Bergera: $840

Congratulations to Melanie and Michaele! We will hear more about these projects at the 2017 AZH annual conference.

We are excited to launch this new grant program in honor of Wendy Andrew, a long standing member of AZH who contributed significantly to our organization. She cultivated so many partnerships and relationships within AZH and we hope this grant program will continue her legacy to grow AZH and our members.

As always, please reach out to any member of the AZH board of directors with questions or concerns.

See you in the garden!

Danielle

 

by azhadminKM

Grow Wise - Bee Smart publication

The Horticultural Research Institute (the research arm of AmericanHort) has developed best management practices for greenhouse and nursery production, woody ornamentals, and managed landscapes. HRI developed the best management practices with help from researchers and beekeepers from across North America. The information is intended to reduce grower impact on bee populations due to growing practices. Click on the following link to download Best Management Practices (BMPs) for Bee Health in the Horticultural Industry.

By azhadminKM

Catalpa "Worm" - larval stage

Even though the catalpa worm, Ceratomia catalpae, can quickly defoliate catalpa trees with their sweet tooth for those trees’ foliage, it also provides some benefits to the tree and humans. Mitigating the catalpa worm’s voracious appetite is the catalpa trees’ ability to produce new leaves quickly, even after being completely defoliated three or four times during a single summer. No other tree can withstand this carnage and survive but this onslaught of caterpillars in-turn produces a quantity of dung which fertilizes the tree and everything else in the vicinity of the tree. In addition to this, catalpa worms are prized for fish bait. Their tough skin and tasty innards are perfect for the fisherman’s hook.

By Susan Pierce, Gardener, Pittsburgh Zoo & PPG Aquarium

 

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.”

   

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!

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:

http://extension.missouri.edu/p/IPM1019-8

http://ag.auburn.edu/enpl/bulletins/catalpasphinx/catalpasphinx.htm

 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

 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