Days of record-breaking high temperatures, little rainfall, humidity under 10 percent ... so describes this monsoon season which is quickly passing. If you are a dirt-under-the-nails gardener or simply a casual observer of your surroundings, it has become apparent that the desert appears “different”or “changed” this year. As an example, let’s take a look at The Arid Garden, a demonstration garden just off Camino Encanto in Desert Hills.
This old public garden consists primarily of plants that are native or desert adapted, and therefore are low water users, tough enough to be referred to as “survivors.” Keep in mind that even xeric gardening means low water use, not “no water.” Because the 34-year-old drip irrigation system throughout the garden had become brittle with repeated and unexpected leaks, volunteers and friends have recently undertaken a complete upgrade of the 34-year old system.
Even with more reliable irrigation, climatic conditions have made it necessary to add another regular weekly watering cycle, and occasionally further supplementing by hand watering. Due to continued hot and dry conditions, many plants appeared stressed, often with “cupped” or wilted leaves, especially in mid-afternoon. Growth slowed, some seasonal blooming stopped, and a few plants died.
Holly Agaves particularly can turn yellow in the heat. With extra water and shade cloth covers, these accent plants should survive and return to their green color as the days cool.
Sweet-scented Kidneywood tree was a month late blooming then leafing out. Robust summer blooming Lantana plants produced buds but delayed opening them. Foliage of perennials including Blanket Flower, Globe Mallow, Pincushion, Paperflower, and Gaillardia simply dried up and disappeared. Usually dense, summer blooms of Trumpet Flowers on the fences have had only a few bright flower clusters.
The garden’s old Society Garlic plant looked somewhat stressed with the heat but, being another survivor, it was expected to rebound. Then one day, it simply disappeared! The root mass has been left in the ground and will be occasionally watered, so it may one day reappear.
Cactus response to the hot, dry summer made an interesting study. Trichocereus, the columnar cactus with multiple large, dazzling flowers, bloomed on cue in March. When monsoon season officially arrived buds were set, even showing petal color as though ready to open. However, many buds stopped at that point and slowly dried, closing completely without finishing their blossom production.
In contrast, the climbing Apple Cactus (Harrisa bonplandii) that wanders throughout an old Palo Verde tree was not stressed by the rugged summer. It still produced more than two dozen large, white flowers within a few nights. Uniquely, the flowers on this plant open at night but begin to close and deteriorate one hour after sunrise. Photographers must be up early to catch this picture!
Mexican Sunflowers in this garden receive morning-to-noon sun and heavily wilt when temperatures are high. Within minutes of a deep soaking, the plants once more stand upright. The same is true of many Salvia greggii hybrids. This year, even reliable Texas Rangers are individually bursting into flower when they choose, instead of all blooming simultaneously as in past years.
The same as many facets of modern conditions, the present monsoon season has been unique and challenging. However, by recognizing the changes and understanding how to cope with them, stress can be reduced for both the garden and the gardener.
Mary Kidnocker is a University of Arizona Master Gardener who lives in the Green Valley area. Her articles are featured weekly.