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Saturday, February 25, 2017

Thoughts on California Native Plants Lecture 9 Notes

Before we begin to think about how to grow California native plants, let's think about why we might want to grow California native plants. The native vegetation, through evolution, is adapted to this climate, these soil types and interacts with other natives (insects, mammals, birds, reptiles) in an ecological dance that was going on long before humans arrived, and certainly before the present civilization of humans arrived on scene. Their niche in the ecology of California gain some advantages to the gardener:

They Save Water
Once established, many native plants need little or no irrigation. Not only does one save the limited amount of water we have available, that saves one money.

Lower Maintenance
Less pruning and no fertilizers mean less work for a gardener, saving time to learn more propagation and take more courses at UCLA Extension

Pesticide Freedom
Native plants interact with the insects of their environment in a way that eliminates pesticide use. The pests and diseases evolved with the plants and native plants have their own defense against them. Beneficial insects often become collateral victims when we spray pesticides (even more true if we use organic methods). Stop poisoning ourselves and our world.

Invite Wildlife
Native plants, birds, butterflies, beneficial insects, and interesting critters are, as noted above, co-evolved to be here. Current research confirms what many have intuited for many years: native wildlife clearly prefers native plants. California’s wealth of insect pollinators can improve fruit set in your garden, while a variety of native insects and birds will keep your landscape free of mosquitoes and plant-eating insects. Open your garden to these wild living things that live among us, despite what we have done to their habitat.

Support Local Ecology
While creating native landscapes can never replace natural habitats lost to development, planting residential and commercial gardens, parks, and roadsides with California natives can provide a “bridge” to nearby remaining wildlands.

California native plants are a world unto their own, mostly because we have so little familiarity with them. By that I mean, our culture's experience with growing these plants is something like 250 years – many a good deal less, like 60 years. And that is also the time we've been selecting them for our gardens. On the other hand, beans, lettuce, cabbage, onions have been in cultivation for thousands of years. Over that time, civilizations have selected year after year those plants that adapt to our culture, or in the case of stubborn plants, we have figured out how to make that plant grow to suit us. This selection process has yet to occur for California natives. Add to that the fact that these are plants from the driest of the world's Mediteranean climate that have adapted to survive with cool, wet winters and long, hot, droughty summers, in a land ravaged by frequent wildfires and you have plants that are, by nature, not ready to accept the regimen we intend to use to make them grow.

The cycle that California native plants live by is almost perfectly backwards to the cycle by which we want to make them grow. We want to plant in Spring (along with our tomatoes and marigolds) and have flowers blessing our landscape by July, if we insist on this, we will spend much more money on therapy than plants! Plant California natives in fall, when we hope for rain to establish them, and enjoy the fecundity of flowers in March/April. Right now, in the California native garden, some salvias are blooming, I've seen Blue Eyed Grass and some poppies blooming. By mid-March, the scene is breathtaking!

In the wild, seed dormancy is usually overcome by the seed spending time in the ground through a winter period and having its hard seed coat softened up by frost and weathering action. By doing so the seed is undergoing a natural form of "stratification" or pretreatment. This cold, moist period triggers the seed's embryo, its growth and subsequent expansion eventually break through the softened seed coat in its search for sun and nutrients.

Meeting some of these conditions, for most gardeners can be a tad difficult. In order to imitate conditions that would ameliorate these inhibitors, one must understand the process the seed goes through in real life in order to mimic it.

Being essentially wild plants, these plants employ many different mechanisms to ensure that at least some of the seeds will find conditions acceptable to carry on the family name. These mechanisms can create wacky germination of their seeds that drive gardeners batty but can be imitated, if one knows the mechanisms a given plant uses to germinate at the most propitious moment for plant survival include:
germination after a fire
germination after cooler temperatures indicate winter
germination as daylight gets longer, indicating more longer days
germinating over a long period of time to have at least some of them hit ideal growing conditions

In most plants of the world, the process of stratification is to simulate cold winter conditions which most wild plants have mechanisms to prevent premature sprouting that would have small plants killed by cold while they are still very tender.

Stratification is the process of subjecting seeds to both cold and moist conditions. Typically, temperatures must be between 34°F and 41°F. The term can be traced to at least 1664 in Sylva, or A Discourse of Forest-Trees and the Propagation of Timber, Vol. II. where seeds were layered (stratified) between layers of moist soil and exposing these strata to winter conditions. Thus, stratification became the process by which seeds were artificially exposed to cold-moist conditions between layers of soil or peat to encourage subsequent germination in spring. Seed of many trees, shrubs and perennials require these conditions before germination will ensue.

In its most basic form, when the stratification process is controlled, the pretreatment amounts to nothing more than subjecting the seeds to storage in a cool (ideally +34° to +36°F; just above freezing) and moist environment for a period found to be sufficient for the species in question. This period of time may vary from one to three months.

To accomplish this you merely place the seeds in a sealed plastic bag with moistened vermiculite 
or even a moistened paper towel
and refrigerate it. Use three times the amount of vermiculite as seeds. It is important to only slightly dampen the vermiculite, as excessive moisture can cause the seeds to grow moldy in the bag.
The medium must be sterile and must be appropriate to the seed's habitat.  We would probably find vermiculite or sand to be most appropriate while peat will not be as appropriate for CA natives.

The medium must be sterile and must be appropriate to the seed's habitat.  We would probably find vermiculite or sand to be most appropriate while peat will not be as appropriate for CA natives.

After undergoing the recommended period of stratification, the seeds are ready to be removed and sown in the nursery bed for germination. Alternatively, the seed may be sown in small pots filled with moist soil and then the whole thing enclosed inside a plastic bag before placing inside a common refrigerator.

In the case of fire causing germination, is it the heat, the chemical residue left by the fire or both that causes the seed to germinate when there is less competition for natural resources? If it is chemical, the commercially available 'Liquid Smoke' could be added via the initial watering and that might unlock germination.

If it is heat, one will need to start a fire over the seeds to get the heat. For example, in germinating Matilija Poppy (Romneya coulteri) the fire that would burn around these seeds in nature, would be composed primarily of Coast Live Oak (Quercus agrifolia) leaves. When I want to start Matilija Poppy from seed, I cover them with dry Live Oak leaves, combined with few dried pine needles, and set them on fire. My thought is that the temperature, the chemistry needed for the poppy to sprout will best be approximated by those leaves of the oak that is a predominant species in the Matilija Poppy's habitat. I might be just a little too fixed on this, but my poppy germination has been excellent. Remember, should you do this, you must not use a plastic container!

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