Horticulture Visit 11/06

I was lucky enough to be able to spend part of the morning with a new friend, a horticulturist at the Zoo. I followed him as he worked, and he taught me about several of the plants we passed and some of the challenges they faced “keeping green” in the animal exhibits. We began in the enclosure that will soon house the two ten-month-old grizzly cub brothers, found orphaned and wandering alone in Alaska. They’ve been working very hard on making the exhibit as comfortable, natural, and entertaining for the bears as possible, and it really shows! The picture shows only about half of the exterior enclosure.

I found out that the soil in the exhibit, and many others along Bear Canyon, is really only about six inches deep; it sits in a large indentation in the exhibit’s concrete base. That’s a challenge in itself when trying to grow large, healthy, nice looking plants. Throw in big, heavy animals that completely compact the soil, and you get roots that can’t get air or water. They solved that problem by mixing in bark chips, which prevent the soil from compacting. I also learned that the enclosures there, even the pools, are actually suspended. Behind each is a doorway that opens underneath, allowing easy access to plumbing.

Giant timber bamboo grows in abundance throughout the area, some so thick it takes both hands to encompass it. I learned that it incorporates silica into its cell structure, making it extra hard. It can leech the soil fairly quickly, so it’s important not to rake up the dropped leaves, as they decompose and replenish the silica in the ground. The younger bamboo stems are coated in a white chalk-like substance, which acts as a water-proof layer. This keeps the young stems from rotting until they have incorporated enough silica into their cells to make them tough and water resistant on their own.

We spent the rest of the time nearby in Sun Bear Forest. One of the really bright vivid plants there is the pink powder puff, which is in the pea family. Its multi-stamen bloom reminds me of a mimosa, and it’s about as pink as pink can be. There’s a red version as well called the Brazilian fire bush. We went up into a back area to confirm the plant’s family in the Sunset Western Garden Book, which is an awesome reference. There was a binturong half-snoozing in his enclosure next to us, but apparently we weren’t doing anything very interesting.

Back down in the main area, I started to learn a bit about the many, many types of palms living in the Zoo. The shaving brush palm looks like exactly that: an inverted shaving brush. The leaves are not widely spread as with other palms. It’s one of the “self-cleaning” palms. As bottom leaves die off, they fall to the ground, leaving a smooth visible trunk. Some other varieties of palms don’t lose their dead leaves; dead leaves cling to the bottom layers as new leaves grow from the top.

The lady palm looks more like a big potted plant than a tree. The leaves are fan-like rather than feather-like, and it has long stems as opposed to a trunk. The bamboo palm is a new favorite of mine. It has feather-like leaves, and the skinny trunk is sectioned somewhat like bamboo. The trunk feels really cool, and it’s a beautiful, rich green. It has a short, squiggly, green inflorescence.

The inflorescence, my word of the week, is the flowering-fruiting part of many palms, and it can vary widely between species. It is a flower of sorts in itself, but more accurately it is a group of stems that holds clusters of flowers, which can look like a bunch of bumps. All of these palms’ flowers and fruit are contained on the inflorescence. We saw a king palm with a large conspicuous red cluster of fruit and a fishtail palm with a beige-green inflorescence hanging down that had to be about six feet long. Fishtail palms are one of the faster of the slow-growing palms. Once it begins to flower, it means the tree itself is beginning to die.

As we were wrapping up our learning session, a flower was pointed out to me that I believe is secretly the best smelling thing in the Zoo. Hidden behind a giant, gorgeous clump of two different gingers in front of the lion-tailed macaques is a tiny white flower called the Honolulu rose. It also goes by glorybower and stickbush, but I like the rose name best. It is so incredible that I’ve since made it a point to walk by just to smell them! No offense to the ginger, which smells great, but the Honolulu rose has my vote. That ended my first horticultural lesson. Super special thanks to my incredible teacher!