|Desert wildflowers, March 16, 2008|
Yet as immigrants arrived, homesick for eastern woods and English gardens, they created landscapes of familiar plants. Developers, trying to entice newcomers, created landscapes reflecting a tropical paradise rather than our own California paradise. The ready availability of water for irrigation allowed gardeners to try their hands at plants from all over the world with remarkable success. The result of all of this is that today gardens and landscapes across the country exhibit the same kind of conformity as shopping malls. Thirsty impatiens color gardens in arid lands just as they do those in the wet, semi-tropical climes. We have lost our sense of place.
I made the decision to add native plants to my garden as a way to acclimate to my new home. I also wanted to use plants that were adapted to our climate, requiring little to no supplemental water, fertilizer or amendments, and hopefully less work. As these plants started to populate my yard I noticed an increase in birds, butterflies, lizards and other wild insects. However, it would be disingenuous to suggest that native plants require little or no care because they are adapted to their locale. To the contrary, native plants, unfortunately, have an undeserved reputation for being difficult to grow, and gardeners new to them sometimes complain of losses in their early attempts.
Different, not difficult
To understand this paradox we need to consider both the plants and the garden. Beginning with the plants, it is important to define what we mean by “native.”
To some, plants that grow in areas undisturbed by humans are native. This neglects the presence and influence of indigenous peoples over many thousands of years throughout the world. A more accurate definition is: Natives are plants that were found in an area before the beginning of Spanish exploration in the 15th Century, an event called the Columbian Exchange. Plants pre-dating this widespread and rapid movement of biological material evolved with local biotic (other plants, animals, and micro-organisms) and abiotic (soil, climate, etc.) conditions over relatively long periods of time. Although people have always transported plants and animals in their travels, the extent and rapidity of this mobility was limited in comparison to what has occurred from the start of the Columbian Exchange to the present. Native plants, therefore, are not those that grow with no human interference, but rather those that evolved with their surroundings over a relatively long period of time.
|Workers preparing plants for sale at Rancho Santa Ana Botanic Garden.|
It would seem that locally native plants would be easy to grow in our gardens since they are adapted to our locale. Where and how native plants are produced, however, also impact how they will grow in the garden. Garden plants, even natives, are typically grown commercially. The goal of the grower is to produce a large number of healthy plants that are ready for sale as quickly as possible. If the grower cannot do this, he or she will be out of business lickety-split.
Most native plants, and non-natives, are propagated by cuttings. The plants are rooted in sterile conditions. Once rooted, the object is to get them ready for market by growing them rapidly while controlling for pests. This is usually done in green houses or under shade cloth to provide ideal exposure, appropriate irrigation, and fertilizers and pesticides as needed.
Next, this pampered young thing is purchased and transplanted into a new environment in which little is controlled. Hopefully it will get some regular water while it settles into its new home, but the soil conditions, exposure, heat, wind, and pests are no longer managed. Furthermore, often the new caretaker is unfamiliar with the plant and may not know whether it is calling out for water or drowning in it.
Plants native to our region have been selected over eons by nature to survive in our unique Mediterranean climate. Those not occurring in wet, riparian areas have wonderful adaptations to allow them to withstand months of heat and drought. And therein lies the rub. These plants are often susceptible to pathogenic micro-organisms that thrive in moist, warm soils. Growing in nurseries, they accept the warm moisture because the potting medium is sterile. Once placed in our gardens, disease-causing fungi and bacteria become active in warm, wet soil, and native plants adapted to hot and dry soil may succumb to disease.
The obvious answer, then, is to keep them dry during the summer. But alas, these plants are “pampered young things.” They have been accustomed to an abundance of water through their short lives and are not ready for the real world. After a few years in the ground, once their roots have grown into the surrounding soil and they have acquired enough bulk to take them through the dry season, keeping them dry in the summer is often the best way to keep them healthy, but first they need to become established in their new homes. This means we must balance between giving them enough water in summer to keep them alive and encourage some growth, but not so much that they rot out. And it is this balancing act that is somewhat difficult.
To help these plants become established, it is best to plant in late fall to winter so that they do not have to survive the hot, dry summer right after being relocated. They usually require careful watering for the first two to three years as their roots extend into the surrounding soil. Techniques for growing native plants have been covered in the powerpoint presentation, How to Keep ‘Em Alive. (Sorry to say the links to this and other presentations are not working but will be fixed as soon as possible. Check out, tips on watering new plants.) Once one is familiar with how these plants grow and what they need, it will be clear that native plants are not harder to grow, they are just different.
Our gardens, too, differ from wildlands. Soil beneath lawns is often depleted of nutrients and compacted. Garden beds are routinely disturbed by hoeing and weeding, and the addition of soil amendments, fertilizers and pesticides. These soils lack good structure and may have an accumulation of salts and other undesirable chemicals. Garden conditions, in these and other ways, are quite different from the conditions found in undisturbed, open space where native plants thrive. Once again, time often solves this problem, though there are strategies, sometimes based on natural processes, that facilitate the development of healthy soil.
Well, you might ask, non-natives are produced in nurseries and grow in the same poor garden soil, why aren’t they difficult to grow? Common garden plants are horticultural products that have been developed by the “green industry” to accept a broad range of conditions. These commercial ornamentals have been selected and bred over the years for their adaptability and durability. Many of these stalwarts can be grown in Minneapolis, Miami, Denver, and Los Angeles. They are tough. They usually require water throughout the year, but thrive in humidity or aridity if given water as needed, and grow in a wide range of soil types.
Since commercial ornamentals were made for the conditions found in our gardens, why not use them? First, many of these plants do require a fair bit of extra water. Although there is a move toward more drought-tolerant plants, most still require significantly more water and other inputs than local natives. A walk through the garden section of a home improvement store tells the story. Next to the rows of plants are shelves filled with bags of fertilizers, soil amendments, pesticides, and other growing aids.
In addition, non-natives that are especially well-adapted to our climate pose a risk of becoming invasive pests in open space. Most of the invasive plants that so endanger habitat got their toe hold in our gardens.
As mentioned above, probably the most compelling reason for using native plants in our gardens is their important habitat value. Although non-natives can provide food and shelter for some birds, lizards, and butterflies, most wildlife, especially endangered wildlife, are specialists adapted to the vegetation with which they evolved. For example, while butterflies may feed on nectar from native and non-native flowers, their caterpillars are frequently very picky about what they can eat. Since nearly all of our wildlands have been impacted by development, to preserve species and the general health of the planet, we can no longer ignore the habitat value of our own backyards.
A wild garden of natives is relaxing and beautiful
Each time I return to my yard after a hard day in the noise and confusion of life in urban America, my breathing slows as I hear the sounds of birds, smell the spicy scent of wild sages, and see the colorful butterflies floating through the air. There are never any small flags warning of the presence of toxic chemicals in my yard because I never use them. My water bill is low and decreasing as the lawn is gradually being replaced with more appropriate plants. It takes some time to learn about native plants, but the learning is fun and the reward worthwhile.
|Side gate to yard. Red toyon berries and Roger’s Red leaves remind me that although the weather is
warm and sunny, it is fall in Southern California. (December 15, 2011)