Docents of Zilker Botanical Garden
by Nelda Moore
Docents of Zilker Botanical Garden continue to search for knowledge through educational opportunities that will enable them to keep the school children and adults on tours interested, educated and observant.
Marion Alsup, President of the Docents, has invited the public to most of the lectures as she did on August 20 when Jeff Pavlat, a garden designer who serves as president of the Austin Cacti and Succulent Society, presented a power point program to over 30 attendees. Gardeners have had a challenging year experiencing not only the bitter cold of last winter but also the brutal record-breaking temperatures of this long hot summer.
Jeff Pavlat enthusiastically introduced plants of the future—cacti, aloes, and succulents—that are drought tolerant, require low maintenance, and are deer resistant. Most often these can be planted in a group, using odd numbers in soil low in organic content that has been placed on top of the ground. Then a top dressing of gravel or wood mulch can be added around the plants. Some cactus can grow in shade. The blue cactus can tolerate full sun while others need some protection from sun scald during summers such as this one. During the winter these plants need to be shielded from the cold with boxes, blankets and cloth. Some of them can be placed in a heated greenhouse and if an electric heater provides most of the heat, but it is a good idea to have a propane heater as well depending on the persistence of extreme temperatures and the wind. If these etiolate plants are watered during the cold, they can expand and suffer winter kill; therefore, it is best to water only enough to keep the plants from shriveling. Then in the spring when flower buds form slowly increase watering.
Some cold hardy cacti include living rock, monk's hood, tree cholla, claret cup and lace cactus while hardy succulents are shin dagger, agave "sharkskin", blue stool, red yucca, ocotillo, bear grass, and several aloes that can survive around 20 degrees F for short times.
For more information about cacti, aloes and succulents go to www.austincss.com