Sabino Canyon: Plants helping plants

Plants Helping Plants

There are many examples of plants helping other species of plants in Sabino Canyon.

Host Plants and Parasites

Desert mistletoe is a hemi-parasite. It is a plant that lives off of another plant. (A hemi-parasite is partially self-sufficient and partially dependent on the host plant.) In this photograph, the reddish clump on the left side of the tree is mistletoe. It is growing on a paloverde tree. Although it makes all of its own food, the mistletoe's root-like parts get water through the paloverde branches and not directly from the soil.

The berries of the mistletoe are the favorite food of many birds, especially one called the phainopepla. (The phainopepla has a crest on its head; the male looks like a black cardinal.) The seeds inside the berries are sticky.

How do desert mistletoe seeds get "planted" in paloverde trees?

Photograph of mistletoe in paloverde tree

Photograph of mesquite nurse plant with saguago cactus

Nurse Plants

Saguaros are very delicate when they are first beginning to grow. In fact, only one out of every 1,000 seeds survives. Saguaros need protection from the sun and frost and from animal predators. Paloverde trees, like this one, and mesquite trees often offer a young saguaro a safe place. These trees are called "nurse plants" because they protect the growing cactus.

Unfortunately for the nurse plant, when the cactus grows up it often kills its protector by taking most of the rain water with its shallow and complex root system. If the water never gets deep enough to reach the roots of the nurse plant, the plant will die.