An Oasis in the City

Everyone that visits the Houston Zoo surely has an animal that they prefer over any other. People pick their favorite primate, favorite reptile, favorite underwater creature. But how about a favorite plant? The Houston Zoo is home to a lush and diverse array of tropical and native plants, flowers, trees, and various ground coverings.

Our team of horticulture professionals spends over 20,000 hours each year planting, pruning and working tirelessly to keep the landscape healthy, vibrant, and colorful for our animals and guests. The horticulture team at the Zoo is just one group of the many unsung heroes that help us operate on a daily basis. Considerable thought is put into the plant life here, focusing on native Texas species and their place at the Zoo. Our animal enclosures also feature plants that the various animals are accustomed to, highlighting the importance of regional plant life.

On your walk through the Zoo, you’ll be able to see various palms, cycads, and bamboos abound, along with flowers of every color, shape and size. This gorgeous array of vegetation provides some amazing photo opportunities and we certainly encourage you to point your camera at both animals AND plants. The morning light provides for some incredible shots, and there are certainly a plethora of plants to shoot(with your camera!).

While walking through the Zoo, it is very easy to get caught up in rushing to which animal you are going to see next. You should slow down! Grab a seat on a bench, take a deep breath, and enjoy this amazing oasis in the middle of Houston’s metropolis.

Oh yeah, and next time you’re at the Zoo and see one of our horticulture professionals working away, give them a friendly smile and wave!




















Making a Difference With Palm Oil Free Candy

Whether it be a holiday or any other excuse to purchase candies and chocolate, it is important to know exactly what you’re sinking your teeth into. The production of many familiar chocolates involves significant amounts of palm oil. Palm oil is a form of edible vegetable oil produced from the African oil palm tree (Elaeis guineensis) which has been planted on plantations throughout Malaysia and Indonesia, home to some of the world’s most endangered wildlife. Because of the increasing demand for palm oil across the globe, millions of acres of rainforest in Sumatra and Borneo are continually cleared in order to plant and later harvest this ingredient. This destruction of rainforest has resulted in an immense loss of habitat for species like the orangutan. 

Luckily, an organization called the Roundtable on Sustainable Palm Oil (RSPO) recognized this issue and established guidelines in order to promote and educate both producers and consumers on the necessity of sustainable palm oil production. The RSPO offers various certifications for growers that are only awarded after a number of criterion have been met.  By employing these certifications, businesses can now identify with the public and other businesses as an organization that believes in producing sustainable palm oil. The collective efforts of the certified are examples of how even large businesses can be an environmental steward. For more details on the RSPO and their certification process, visit their website.


To make a difference, all you need is a little bit of knowledge and a keen eye. By looking for and purchasing palm oil free products, or products produced by members of the RSPO, we can reduce the demand and slow the staggering rate of habitat loss. Here is a fantastic graphic that can serve as a great palm oil shopping guide.


Click here to enlarge


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There's a New Resident at the Houston Zoo and It's Not an Animal!

There’s a new bud in town.

We are happy to announce that our very own spunky and stinky corpse flower, Pewtunia, is about to bloom!

Our fans know and love all the interesting, diverse and engaging animals that call the Houston Zoo home. However, an aspect of the Zoo that is sometimes overlooked is the incredibly maintained and varied plant life that not only keep the Zoo grounds looking beautiful, but also add a natural enhancement to animal habitats.

One of these resident plants is definitely a standout – our gal Pewtunia is what is known in the horticulture world as an Amorphophallus titanum. We realize that’s kind of a mouthful (we had to re-spell it several times to get it right), so you may know her better as a Corpse Flower, Carrion Plant, Titan Arum or Voodoo Lily.

Originally scientifically described in 1878, discovered by Odoardo Beccari, and only found in Western Sumatra, Corpse Flowers are definitely a rare sight and, ahem, smell. The name Corpse Flower comes from the distinct stench that has been described as the smell of a corpse.

Obviously our dear Pewtunia does not have any dead bodies near her – the smell is really given off, along with extra heat, to attract Carrion Beetles and Blow Flies. These friends to the Corpse Flower are pollinators, which means they are integral to continuing the Corpse Flower population. This attractive (well to bugs anyway) odor will be at it’s most powerful 12-24 hours of full bloom.

It’s rude to ask a lady’s weight, but we’ll tell you that Pewtunia is almost 20 pounds and currently stands 2’6″. She may not sound like a heavyweight yet, but prior to blooming, Corpse Flowers grow rapidly, and she will reach heights of 4′-6′ – maybe even 8′!

Pewtunia as of Thursday, September 8

So if you’d like to experience Pewtunia in all her glory, then start planning your trip to the Zoo now – we think she’ll be in full bloom by or before next weekend! Or maybe you’d prefer to enjoy the view without the smell?

Pewtunia will be viewable in the Zoo on The African Forest walk between the 4-D Experience and the Indoor Chimp Viewing area starting Monday, September 12. And there will be special Horticulture Keeper Talks at 10:00 a.m. and 2:00 p.m. when one of our knowledgeable horticulture staff members will be there to answer any and all Corpse Flower curiosities you may have!

Gift of Grub Series: Browse on Zoo Grounds

Please consider giving a year-end, tax-deductible gift of grub to help feed our animals in the coming year by clicking or our CONTRIBUTE tab on Facebook!

A snack for Toby, the red panda

This month-long series has mentioned so many kinds of foods that are bought or ordered by the commissary, then further prepared and dispensed by keepers. In almost each post you may have noticed the use of the mysterious term “browse” that many of our animals get as well.

A babirusa with fresh browse

Browse simply means the leaves and tender shoots that our animals might come across to nibble on in daily life in the wild.  We duplicate this by providing browse for them in their habitats.  The thing that may be a surprise to our guests is that we grow quite a bit of this browse on grounds.

Our Coquerel Sifaka dives in

We have a large, full-time horticulture team, led by Joe Williams. Like the old phrase, they are at hard at work outside, whether it’s in pouring rain, cold temps, or high humindity. Monday through Friday they spent between four and six hours doing cutting browse, which accrues anywhere from 100 to 200 pounds of it a day!  

Horticulture Manager Joe Williams and some of his team collect browse grown on grounds almost every day

Most of the plants and trees used for browse grow naturally, so they don’t take a lot of time or energy to plant.  We do add ginger, banana and a variety of bamboos, but those are planted in the Zoo’s overall landscape and when they are normally trimmed, that’s used as browse. 

A little nosh for our South American Tapir

At some point, horitculture may plant a browse garden or pockets of browse in a couple locations on Zoo property.  Proper pruning techniques are used to ensure that the health of the plants or he aestheics of the Zoo grounds are not affected.

Written by Rochelle Joseph, and Joe Williams, Horticulture Manager 

Our handsome okapi say gimme some browse!

It takes $600,000 a year to feed our over 6,000 animals at the Houston Zoo. That’s a big bill!

Please consider gifting your furry, feathered and fanged friends this holiday with a tax-deductible donation  during our Gift of Grub campaign at: or click the Contribute button on Facebook!

Rootball Enriches Drylands Inhabitants

Many of our guests are familiar with our enrichment program here at the zoo.  They often watch our animals enjoying novel items or figuring out how to get a treat out of a puzzle feeder.  We give our animals enrichment because it helps keep them mentally challenged and it’s essential to the well being of the animals we care for.

Recently our ace horticulture team saved a  root ball from a tree they had taken out and brought it over to the Natural Encounters building to be given to the animals as enrichment.  The root ball is about four feet across and took five of us to move.  We weren’t sure which exhibit to put it in, but after much deliberation and debate we settled on the Drylands exhibit.  It was an instant hit as you can see from this video.  At first the guinea fowl weren”t sure what to make of this spaceship that landed in their home, but now forage on it regularly.  The antelope ground squirrels moved right in and even the star tortoises enjoy burrowing under it.  The root ball is giving the animals the opportunity to express natural behaviors such as foraging and burrowing, as well as making decisions about whether this new thing should be approached or not.  These types of opportunities are what enrichment is all about.

The root ball will probably be there for a while since it wasn’t the easiest thing to move.  Come by the Drylands exhibit in Natural Encounters and see who’s hanging out on, around or under it!

How To Protect Your Plants During Cold Weather

A Message from Joe Williams, the Houston Zoo’s Horticulture Manager

I’ve had a number of guests and staff asking me about their plants both here and at home after the cold weather of late and what to do with freeze damage. The best thing to do with almost everything at this moment is to leave it alone.
– Don’t trim any woody stemmed plant or perennial until we are certain to not freeze again. The dead and/or unhappy plant matter will help to insulate the rest of the plant if we do freeze again. More importantly, if you cut back to green wood you could promote new growth. This is a huge expense of energy for a plant that is already hurting. Also the new growth is the most sensitive to the cold. The culmination of the energy output and continued damage almost certainly ensures this plant will die.

– Plants such as bananas, gingers, cannas and elephant ears can be trimmed back to the ground and mulched. For these you can trim to just below the damaged portion and they should be content. If there is still green, happy tissue the roots will still be getting energy from the stem which will promote a stronger plant next year. For the most part we are trimming the gingers and bananas just below the damage because we tend to use them as structural components of the gardens and they’ll be walked upon if we are to trim them to the ground. This won’t be a good year to get fruit from our bananas or flowers from our gingers, but the plants will come back. The majority of plants listed above are at least root hardy to anywhere from 10 to 15 degrees Fahrenheit.


– When considering tropical trees, if they are kicking off old leaves, this tends to be a good thing. This means that the tree is still trying to live, normally some sign of bud growth or the trees attempt to eliminate the energy necessary to maintain the leaves and concentrate of root growth. When a tree hold on to dead leaves if tends to be a bad sign. A quick means of checking the potential viability of you trees that do have dead leaves is to attempt to strip a leaf, it should come of fairly easily. This is also works to see if a newly transplant tree is doing alright.

– Now on to palm trees… Most palms that are sold here are supposed to be hardy to at least 20 degrees. This doesn’t mean that nurseries haven’t brought in other more tender palms or that we don’t have a handful of really tropical palms here. Don’t cut any of the ugly dead fronds off until we are certain not to freeze. The most important thing is keep the heart of the palm warm and insulated. This is the area where the leaves emerge from the trunk. The dead leaves give the palm a couple more degrees of cold tolerance. We’ll also wrap or provide heat to palms that we know are sensitive tot the cold. I can provide a list of the palms that are sensitive for any future freezes.


We aren’t going to know for certain the extent of the damage until spring. The good thing about being in Houston is that spring tends to begin in February. As I said before the best thing to do with most plants is just leave them alone. I know it’s tough to look at ugly plants, but for most plants either winter defoliation or being knocked back by freeze is the norm and they’ll come back as strong as ever.

The latest addition to the Houston Zoo landscape will put a spring in your step

The new pathway to the Tropical Bird House
The new pathway to the Tropical Bird House

Four environmentally friendly pathways are the newest additions to the Houston Zoo’s landscape. The new pathways, installed by National Sales and Supply are located near the Brown Education Center, the Tropical Bird House, the entrance to Wortham World of Primates, and the cassowary and hornbill viewing area.

The pathways are made from recycled rubber tires, which accounts for the spring in your step when you walk on them.

A close-up of the new mulch
A close-up of the new mulch

The area at the entrance to Wortham World of Primates will be home to a bronze orangutan statue which will be installed and dedicated early next year.

The recycling process is simple – The tires are first shredded into strips, then ground to smaller pieces where powerful magnets are used to remove the steel fibers from the tires. The rubber from the shredded tires is mixed with a urethane base and the pathway is poured to the desired thickness, shape and form.

How Do We Keep 55 Acres Watered, Especially Now (Part 3)?

Houston Zoo Horticulture Team Member
Houston Zoo Horticulture Team Member

Efficient, intelligent watering is one of the most important factors in gardening.  Rain is, of course, the most effective method of providing water and normally, we receive close to the perfect amount here in Houston.  This year we haven’t seen near enough rain.  When it comes to providing additional water to your plants, there are a number of things to consider.  The most important thing is to provide less frequent, deep watering.  This promotes healthy root and plant growth and ensures that the plant doesn’t stay saturated. 

We always want to ensure that we aren’t wasting water either, there is only so much available.  Currently there may not even be enough water, anybody that is dealing with water restrictions will agree.  Sidewalks don’t need to be watered; those of us that have irrigation it’s important that we make sure that all of our sprinkler heads are hitting the correct areas.  This also goes for when we are watering from a hose as well; shut-off valves are effective and easy to use. It isn’t necessary to water your porch when you are watering your potted plants.   There are a number of watering wands available also, which have diffuser heads that provide a soft shower of water rather than a jet or stream of water.  When the water pressure is too high, the soil doesn’t take in the water as readily and we displace the soil, which impacts the roots and root hairs limiting the plants ability to take in nutrients and water. 

The most effective time to water is during the early morning hours.  When we water during the heat of the day, most water is lost to evaporation and some plants can actually get burnt.  When we water late at night the plants may not be taking in water as readily and there is the possibility of the plants sitting in water, providing opportunity for infection or damage.  This being said, any time that you see a plant needs water, water it.  If a plant dies, there is no amount of care that you can do to bring it back.  Irrigation with a clock timer is a great way to make certain that you are watering at the proper time and that you don’t accidentally leave the water on wasting vast quantities of water. There is always going to be a degree of adjustment, both initially and seasonally, but irrigation on a clock eliminates a number of problem areas.   Also those of you that have irrigation, will be having irrigation installed or that use a hose and are interested, adding a dechlorinator of some type will be very beneficial.  The chlorine and chloramines in our water wreak havoc with the beneficial micro-organisms in our soils, but we will discuss soils a little later.  

There are number of other things I can discuss about irrigation and hand watering, but I could go on forever.  There is no cut and dry water plan that will be effect for everyone.  Each plant requires different amounts of water, even virtually identical plants.  We need to observe the conditions in our gardens.  There’s a pretty big difference between a wilted and an over-watered plant.  Check your soil.  If the soil feels like it is damp, it probably doesn’t need water.  If it feels dry, then it probably needs water.  If when you water the water just runs off, you may need water a little, let the water absorb and then come back later, when the ground is ready to receive water. 

Hopefully this is effective information.  We’ve kept our 55 acres here at the zoo, with 12 horticulturists pretty well watered using them.  Next time, I’ll be discussing soils and how healthy soils can help in keeping our plants watered and happy.

Article written by: Joe Williams, Manager of Horticulture at the Houston Zoo

How Do We Keep 55 Acres Watered, Especially Now (Part 2)?

One of many big oak trees at the Houston Zoo
One of many big oak trees at the Houston Zoo

In the my last entry, I wrote about our dense canopy.  Shade is another important means of keeping plants happy during extreme weather.  It not only keeps the air cooler by preventing the intense sun from getting through, but it also helps the soil retain more water.  If it isn’t as hot, will the water evaporate as quickly?  Unfortunately even big trees that provide the shade also require additional water.  Especially when the temperatures are high and a fair number of trees throughout Texas haven’t been hand watered or irrigated because they haven’t needed it until now.  When we experience temperatures near 100 degrees and haven’t had rain, there just isn’t available ground water.  Another drawback to assessing the water requirements of large trees is that by the time they are showing that they need water it can be too late. 

Most plants appear to appreciate shade of whatever type recently.  We have a number of plants that desire full sun, planted in a fair amount of shade.  With the frequency and the intensity of the sun here, most plants will meet their required light needs.   A negative of planting where the light requirements aren’t met is that plants will become “leggy”, stretching towards the sun with a decrease in the amount of foliage.  We haven’t had a big problem with this.  

 Those of us that have attempted vegetable gardens this summer have seen signs of what the heat and sun can do.  Even when the garden is prepared and planted exactly as it’s recommended, our yield is greatly reduced and normally not as appealing.  There are a few vegetables like squash, corn and okra that don’t miss a beat, but plants such as tomatoes and peppers tend not to even set fruit when the temperature is near 100 degrees.  A method that can be utilized is putting some type of shade structure above your plants, so they are protect during the heat of the day.  This could be as simple as tarp on some type of post such as bamboo, 2×2 lumber or anything that keeps the tarp high enough that it doesn’t actually touch the plants.  Tarps are usable, but there are quite a few, very affordable, shade cloth options, which are available at most home improvement stores or garden centers. 

 In summation, when temperatures are this high, plants need shade.  Providing some means of protection from intense sun and heat for your plants could be just enough help to keep them alive and thriving.  Look for my next post, where I discuss irrigation and hand watering.

Article written by: Joe Williams, Manager of Horticulture at the Houston Zoo

How Do We Keep 55 Acres Watered, Especially Now? (Part 1)

Texas Star Hibiscus at the Houston Zoo
Texas Star Hibiscus at the Houston Zoo

Most gardens, and people for that matter, in Texas are being severely impacted by the utter lack of rain and the consistent 100 degree temperatures, we here at the zoo are no different.  There aren’t many plants that are happy when we have temperatures this high and most actually stop growing when the temperature is too hot.  Our plants, animals and horticulture department are quite lucky that we have such a dense canopy covering most of the zoo, but when we don’t get rain and have high temperatures, even our mature canopy is at risk.

 One of the most important things to do, to ensure your plants and garden remain viable during periods like this, is to select plant material that is either native to this area or tolerant of the conditions that can be presented.  Native plants are acclimated and have adapted to the local environment.  This being said, our being a zoo, it is all but mandated that we use non-native plants and trees in our various exhibits and gardens.  How often do you see Grizzly Bears and a Texas Sabal Palm?  Their native ranges don’t overlap, but we have Grizzlies and need to present them in a naturalistic exhibit, with plant material that’s either from their range or equivalent.  This is both for the well-being of the bears and for the education of our visitors.  We strive to use suitable native representatives when we are able, but there are understandable constraints.

 Even though plants are native, it doesn’t mean that they are anywhere near prepared for 100 degree temperatures and no rain.  We normally receive close to 6 inches of rain in June and have temperatures, at least, 5 degrees cooler.  Even natives aren’t prepared for this.  There are a few other things that we do to give our plants every advantage possible.  Look forward for my next blog, when I discuss this further.

Article written by: Joe Williams, Manager of Horticulture at the Houston Zoo

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