Tim Allen, the Zoo's first full-time horticulturist, had already had a full career when he started at the Zoo in 1955. He had worked at the San Diego County Department of Agriculture and had just taken early retirement when Ralph Virden, Zoo superintendent of buildings and grounds, called and asked if he'd like to come work for the Zoo. At first Tim said no; but when Ralph called a second time, he said, "Well, I'll take a chance and see if you like me, and I'll see if I like you for about six months or a year." He ended up staying for 15 years. During that time, Tim initiated dividing the Zoo into sections for care and watering, so that each gardener could focus on making their section the best it could be; established a browse program to grow the Zoo's own acacia to feed giraffes and okapis and eucalyptus to feed koalas; and started the Zoo's collections of rare cycads, ficus, and tree ferns. He also kept an eye out for opportunities to collect other rare plants for the Zoo, and he was instrumental in obtaining some very valuable donations of individual plants and even large collections over the years.